JP2004244301A - Piezoelectric ceramic composition, method for producing the same, piezoelectric element and dielectric element - Google Patents

Abstract

A not contain lead, high have piezoelectric properties and dielectric properties, in particular the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, and a piezoelectric ceramic composition excellent in any one or more of dielectric constant and a manufacturing Provided are a method, and a piezoelectric element and a dielectric element using the piezoelectric ceramic composition.
A general formula is represented by _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x It is a piezoelectric ceramic composition containing, as a main component, a compound having a composition range of ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2. The piezoelectric ceramic composition contains at least one metal element selected from Mg, Ca, Sr, and Ba as an additive element. The total content of the additional elements is 0.0001 mol to 0.10 mol per 1 mol of the compound represented by the general formula.
[Selection diagram] None

Description

  The present invention relates to a piezoelectric ceramic composition containing no lead in the composition, a method for producing the same, and a piezoelectric element and a dielectric element using the piezoelectric ceramic composition as a material.

Conventionally, a PZT (PbTiO ₃ -PbZrO ₃ ) component-based ceramic containing lead has been used as a piezoelectric ceramic composition. This is because PZT exhibits large piezoelectricity and has a high mechanical quality factor, and can easily produce materials having various characteristics required for each application such as a sensor, an actuator, and a filter.
Further, since the PZT has a high relative dielectric constant, it can be used as a capacitor or the like.

However, while the piezoelectric ceramic composition comprising PZT has excellent properties, it contains lead as a constituent element, so that harmful lead is eluted from industrial waste of products containing PZT, resulting in environmental pollution. Could be caused. And, increasing awareness of environmental issues in recent years has made it difficult to manufacture products that can cause environmental pollution, such as PZT. Therefore, development of a piezoelectric ceramic composition containing no lead in the composition has been demanded, and a piezoelectric ceramic composition represented by the general formula (K _1-x Na _x ) NbO ₃ (where 0 <x <1) (See Non-Patent Document 1).

However, the piezoelectric ceramic composition represented by the general formula (K _1-x Na _x ) NbO ₃ (where 0 <x <1) has a piezoelectric d ₃₁ constant, an electromechanical coupling coefficient Kp, a piezoelectric g ₃₁ constant, There is a problem that the piezoelectric characteristics such as the mechanical quality factor Qm are low. Therefore, for example, high piezoelectric d ₃₁ constant, a piezoelectric actuator that requires an electromechanical coupling factor Kp, piezoelectric filters, piezoelectric transducers, piezoelectric transformers, piezoelectric ultrasonic motor, a piezoelectric gyro sensors, knock sensors, yaw rate sensors, airbag sensors, It has been difficult to apply to piezoelectric elements such as back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, and piezoelectric igniter.

Further, the piezoelectric ceramic composition represented by the above general formula has a low dielectric property such as a relative dielectric constant ε _33T / ε ₀ and a dielectric loss tan δ, so that it is difficult to apply the composition to a dielectric element such as a capacitor. there were.
"Journal of the American Ceramic Society", USA, 1962, Vol. 45, no. 5, p. 209

The present invention, such conventional been made in view of the problems, does not contain lead, have high piezoelectric properties and dielectric properties, any particular piezoelectric d ₃₁ constant, the electromechanical coupling factor Kp, and the relative dielectric constant An object of the present invention is to provide a piezoelectric ceramic composition and a method of manufacturing the same, and a piezoelectric element and a dielectric element using the piezoelectric ceramic composition.

The first invention of the general formula represented by _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w, respectively 0 A piezoelectric ceramic composition mainly comprising a compound having a composition range of ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2,
The piezoelectric ceramic composition contains, as an additive element, at least one metal element selected from Mg, Ca, Sr, and Ba.
The piezoelectric ceramic composition according to claim 1, wherein the total content of the additional elements is 0.0001 mol to 0.10 mol per 1 mol of the compound represented by the general formula (claim 1).

The second invention are represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w is A piezoelectric ceramic composition containing, as a main component, a compound in a composition range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2,
The piezoelectric ceramic composition contains, as an additive element, at least one metal element selected from Si, In, and Sc.
The piezoelectric ceramic composition is characterized in that the total content of the additional elements is 0.08 mol or less based on 1 mol of the compound represented by the general formula (claim 3).

A third aspect of the present invention is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w is A piezoelectric ceramic composition containing, as a main component, a compound in a composition range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2,
The piezoelectric ceramic composition contains Bi as an additional element,
The piezoelectric ceramic composition according to claim 5, wherein the content of the additional element is 0.0001 mol to 0.004 mol per 1 mol of the compound represented by the general formula (claim 5).

Next, the operation and effect of the first to third inventions will be described.
The piezoelectric ceramic compositions of the first to third inventions do not contain lead in the compositions.
Therefore, the piezoelectric ceramic composition is safe because harmful lead does not leak from the waste and the like to nature.

Further, the piezoelectric ceramic composition has a compound represented by the above general formula as a main component, and x, y, z, and w in the above general formula are respectively in the above ranges.
Therefore, the piezoelectric ceramic composition has piezoelectric properties such as a piezoelectric d ₃₁ constant, an electromechanical coupling coefficient Kp, a piezoelectric g ₃₁ constant, a mechanical quality factor Qm, and a relative dielectric constant ε _33T / ε ₀ and a dielectric loss tan δ. It has excellent dielectric properties and Curie temperature Tc.
Note that does not contain the additive element, a composition represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, less Where appropriate, referred to as the "basic composition".

The piezoelectric ceramic composition according to the first aspect of the invention includes, in addition to the compound having the basic composition represented by the general formula, at least one metal element selected from Mg, Ca, Sr, and Ba as an additional element. It is contained within the above content range.
The piezoelectric ceramic composition according to the second aspect of the present invention includes, as an additive element, at least one metal element selected from Si, In, and Sc in addition to the compound having the basic composition represented by the general formula. It is contained within the above content range.
Further, the piezoelectric ceramic composition of the third invention contains Bi as an additive element in the above content range in addition to the compound of the basic composition represented by the general formula.
Therefore, the piezoelectric ceramic compositions according to the first to third _{aspects of the present} invention are particularly improved in at least one of the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, and the relative dielectric constant ε _33T / ε _0. It is even better than a piezoelectric ceramic composition represented by the above general formula and not containing the above-mentioned additive element.
In the first to third aspects of the present invention, the piezoelectric ceramic composition may contain the additive element by substitution addition to the compound represented by the general formula. It may be contained by being externally added to the compound represented by the formula.

As described above, the piezoelectric ceramic compositions of the first to third inventions are safe for the environment because they do not contain lead, and have excellent piezoelectric characteristics, so that they can be used as high-performance piezoelectric elements. can do.
Further, the piezoelectric ceramic composition is excellent in dielectric properties such as relative permittivity and dielectric loss in addition to the above piezoelectric properties. Therefore, the piezoelectric ceramic compositions of the first to third inventions can be used as high-performance dielectric elements. That is, the piezoelectric ceramic composition is a concept including not only a piezoelectric ceramic composition having piezoelectric characteristics but also a dielectric ceramic composition having dielectric characteristics.

Next, the fourth invention is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w Are compounds having composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2, respectively, and 1 selected from Mg, Ca, Sr, and Ba. There is provided a method for producing a piezoelectric ceramic composition, which comprises mixing an additive containing at least one kind of metal element and firing the mixture.

A fifth aspect of the present invention is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w is A compound having a composition range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2, respectively, and one or more compounds selected from Si, In, and Sc A method for producing a piezoelectric ceramic composition, comprising mixing and firing an additive containing a metal element (claim 27).

Further, the sixth invention is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w is Compounds having composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4 and 0 <w ≦ 0.2, respectively, and an additive containing Bi are mixed and fired. There is provided a method for producing a piezoelectric ceramic composition, which is characterized by the following (claim 28).

In the fourth to sixth inventions, any mixture obtained by mixing the compound represented by the general formula and the additive can be sintered under normal pressure. Therefore, sintering can be performed easily and at low cost. The piezoelectric ceramic composition obtained after the calcination does not contain lead, and having excellent dielectric characteristics such as piezoelectric properties and dielectric constant and dissipation factor, such as a piezoelectric d ₃₁ constant and electromechanical coupling factor Kp Become. Therefore, it can be used as a material for a high-performance piezoelectric element or dielectric element.
Further, in the production methods of the fourth to sixth inventions, the metal element may be substituted or externally added to the compound represented by the general formula.

  Further, in the fourth invention, the piezoelectric ceramic composition obtained after the firing is added with the additive, and as a result, any one of Li, K, and Na of the compound represented by the general formula is added. At least a part of the above may be substituted with any one or more metal elements selected from Mg, Ca, Sr, and Ba, or may be a compound such as an oxide or a perovskite structure compound containing the metal element or the metal element. , Etc., in the grains or grain boundaries in the piezoelectric ceramic composition.

  In the fifth invention, the piezoelectric ceramic composition obtained after the firing is added with the additive, and as a result, any one of Nb, Ta, and Sb of the compound represented by the general formula is added. At least a part of the species is replaced by any one or more metal elements selected from Si, In, and Sc, and is contained as a metal element or an oxide or a perovskite structure compound containing the same. It is contained in the inside of a grain, a grain boundary, and the like in the piezoelectric ceramic composition.

  In the sixth invention, the piezoelectric ceramic composition obtained after the firing is added with the additive, and as a result, any one of Nb, Ta, and Sb of the compound represented by the general formula is obtained. At least a part of the species is replaced with Bi and contained as Bi or an oxide or a compound containing a perovskite structure compound containing the same, such as in a grain or a grain boundary in the piezoelectric ceramic composition. Or

Next, a seventh invention relates to a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb. the general formula after calcination _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) is represented by O _3, and x, y, z, w respectively 0 ≦ x ≤ 0.2, 0 ≤ y ≤ 1, 0 <z ≤ 0.4, 0 <w ≤ 0.2 at a stoichiometric ratio which results in a compound in the composition range, or contained in the following additives: Characterized in that they are prepared in a stoichiometric ratio in consideration of the substitution with the metal element to be performed, and further mixed with an additive containing at least one metal element selected from Mg, Ca, Sr, and Ba, and fired. (Claim 29).

The eighth invention relates to a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb. , after firing the general formula _{{Li x (K 1-y} Na y) 1-x} is represented by _{(Nb 1-zw Ta z Sb} w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2,0 ≦ y ≦ 1,0 <z ≦ 0.4,0 <w ≦ 0.2 at a stoichiometric ratio which results in a compound in the composition range, or contained in the following additives: A stoichiometric ratio in consideration of substitution with a metal element, further mixing an additive containing at least one metal element selected from Si, In, and Sc, and firing. A method for producing a porcelain composition is provided (claim 31).

The ninth invention is directed to a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb. , after firing the general formula _{{Li x (K 1-y} Na y) 1-x} is represented by _{(Nb 1-zw Ta z Sb} w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2,0 ≦ y ≦ 1,0 <z ≦ 0.4,0 <w ≦ 0.2 at a stoichiometric ratio which results in a compound in the composition range, or contained in the following additives: (Claim 33). A method for producing a piezoelectric ceramic composition, characterized in that a stoichiometric ratio is prepared in consideration of substitution with Bi atoms, and an additive containing Bi is mixed and fired.

According to the seventh, eighth, or ninth aspect, the piezoelectric ceramic composition of the first, second, or third aspect can be easily manufactured.
Further, in the seventh to ninth inventions, the calcination can be performed under normal pressure.
Therefore, the piezoelectric ceramic composition can be manufactured easily and at low cost. Then, the piezoelectric ceramic composition obtained after the above-mentioned firing does not contain lead and has excellent piezoelectric characteristics and dielectric characteristics. Therefore, it can be used as a material for high-performance piezoelectric elements and dielectric elements.

  In the seventh invention, the piezoelectric ceramic composition obtained after the firing is added with the additive, and as a result, any one of Li, K, and Na of the compound represented by the general formula is added. At least a part thereof is replaced with any one or more metal elements selected from Mg, Ca, Sr, and Ba, or the metal element or an oxide or a compound such as a perovskite structure compound containing the metal element. May be contained in the above-mentioned piezoelectric ceramic composition in the grains or grain boundaries.

  In the eighth invention, the piezoelectric ceramic composition obtained after the firing is added with the additive, and as a result, one of Nb, Ta, and Sb of the compound represented by the general formula is added. At least a part thereof is replaced with any one or more metal elements selected from Si, In, and Sc, or is contained as a compound such as an oxide or a perovskite structure compound containing the metal element or these. It is contained in the inside of a grain, a grain boundary, and the like in the piezoelectric ceramic composition.

  In the ninth aspect, the piezoelectric ceramic composition obtained after the firing is added with the additive, and as a result, any one of Nb, Ta, and Sb of the compound represented by the general formula is obtained. At least a part of the above is contained in the piezoelectric ceramic composition in a grain or a grain boundary in the piezoelectric ceramic composition, as being contained by substitution of Bi, or as a Bi atom or an oxide containing the same or a compound such as a perovskite structure compound. Or

  In the seventh to ninth inventions, the compound containing Li, the compound containing Na, the compound containing K, the compound containing Nb, the compound containing Ta, and the compound containing Sb And the above-mentioned additive are mixed at a stoichiometric ratio in consideration of substitution by a metal element or Bi atom contained in the additive, Li and Na in the compound represented by the above general formula are mixed. , K, Nb, Ta, and Sb can be at least partially replaced with a metal element or Bi atom contained in the additive.

In the seventh and eighth aspects of the present invention, “prepared at a stoichiometric ratio in consideration of substitution by a metal element contained in an additive”, and in the “ninth aspect of the invention,” a Bi atom contained in an additive is prepared. Is prepared in stoichiometric ratio in consideration of substitution by a compound, for example, when Li of the compound represented by the above general formula is substituted with the metal element or Bi atom of the additive, the amount of the compound containing Li is reduce, with added to and mixed with only the additives that reduce the amount, as a whole, the general formula after calcination _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w ) It can be realized by preparing at a stoichiometric ratio such that the compound represented by O ₃ is synthesized.

  In the case of substituting K, Na, Nb, Ta, and Sb in the above general formula, the amount of the compound containing these is reduced, and the additive containing the metal element or Bi atom to be substituted is reduced accordingly. It can be realized by adding.

On the other hand, after or before calcination calcination, the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) represented by O ₃ is a compound such chemical In a stoichiometric ratio, a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb were prepared. The piezoelectric ceramic composition containing the additive as a compound such as the metal element, Bi, or an oxide or a perovskite structure compound containing the metal element, Bi, or the like by further mixing the additive with the additive. Can be.

  According to a tenth aspect, there is provided a piezoelectric element having a piezoelectric body made of the piezoelectric ceramic composition of the first to third aspects (claim 35).

The piezoelectric element according to the tenth aspect has a piezoelectric body made of the piezoelectric ceramic composition according to the first to third aspects. Therefore, the piezoelectric element does not contain lead and is environmentally safe.
Further, the piezoelectric element, the piezoelectric ceramic composition has, can be used as it is characteristic that piezoelectric properties such as piezoelectric d ₃₁ constant is excellent. Therefore, the above-mentioned piezoelectric element is a highly sensitive piezoelectric sensor element, a piezoelectric actuator having high electromechanical energy conversion efficiency, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, a piezoelectric ultrasonic motor, a piezoelectric gyro sensor, a knock sensor, a yaw rate sensor, It can be used as a piezoelectric element such as an airbag sensor, a back sonar, a corner sonar, a piezoelectric buzzer, a piezoelectric speaker, and a piezoelectric igniter.

  An eleventh invention is directed to a piezoelectric element having a piezoelectric body made of a piezoelectric ceramic composition manufactured by the manufacturing method according to the fourth to ninth inventions (claim 36).

  The piezoelectric element according to the eleventh aspect has a piezoelectric body made of the piezoelectric ceramic composition obtained by the manufacturing method according to the fourth to ninth aspects. Therefore, the above-mentioned piezoelectric element is a piezoelectric sensor element having high sensitivity, a piezoelectric actuator having a high electromechanical energy conversion efficiency, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, a piezoelectric transformer, taking advantage of the excellent characteristics of the piezoelectric ceramic composition. It can be used as a piezoelectric element such as an ultrasonic motor, a piezoelectric gyro sensor, a knock sensor, a yaw rate sensor, an airbag sensor, a back sonar, a corner sonar, a piezoelectric buzzer, a piezoelectric speaker, and a piezoelectric igniter.

  A twelfth aspect of the present invention is a dielectric element having a dielectric comprising the piezoelectric ceramic composition of the first to third aspects.

  The twelfth aspect of the present invention provides a dielectric element comprising the piezoelectric ceramic composition of the first to third aspects. Therefore, the dielectric element does not contain lead and is environmentally safe. Further, the dielectric element can utilize the property of the piezoelectric ceramic composition, which is excellent in relative permittivity and dielectric loss, as it is. Therefore, it can be used as a capacitor having a large capacitance.

  A thirteenth invention is a dielectric element having a dielectric comprising a piezoelectric ceramic composition manufactured by the manufacturing method according to the fourth to ninth inventions (claim 38).

  The dielectric element according to the thirteenth aspect has a dielectric made of the piezoelectric ceramic composition obtained by the manufacturing method according to the fourth to ninth aspects. Therefore, the dielectric element can be used as a capacitor or the like having a large capacitance by utilizing the excellent characteristics of the piezoelectric ceramic composition as it is.

Above in the invention of the first invention to the ninth, the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) compound represented by the O ₃ is, x , Y, z, and w are in the range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2, respectively.
Here, x> 0.2, z> 0.4 , w> 0.2, in the case of z = 0, or w = 0, the piezoelectric characteristics and dielectric characteristics such as a piezoelectric d ₃₁ constant is reduced, desired It may not be possible to obtain a piezoelectric ceramic composition having the following characteristics.
In the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) compound represented by O _3, the range of y is, 0 ≦ y ≦ 0. It is more preferably 85, and further preferably 0.05 ≦ y ≦ 0.75. In these cases, the piezoelectric d31 constant and the electromechanical coupling coefficient Kp of the piezoelectric ceramic composition can be further improved. Still more preferably, 0.05 ≦ y <0.75, more preferably 0.35 ≦ y ≦ 0.65, and even more preferably 0.35 ≦ y <0.65. Most preferably, 0.42 ≦ y ≦ 0.60 is good.

As described above, the piezoelectric ceramic composition contains a compound having a perovskite structure (ABO ₃ ) as a main component. In the present invention, the element configuration of the A site in the perovskite structure (ABO ₃ ) corresponds to K, Na or K, Na, and Li, and the element configuration of the B site corresponds to Nb, Ta, and Sb. In the composition formula of the perovskite structure, when the stoichiometric ratio of the atoms constituting the A site and the atoms constituting the B site is 1: 1, a complete perovskite structure is obtained. In particular, K, Na, Li, and Sb are volatilized by several%, specifically, about 3% in a firing step or the like, and all constituent elements are mixed by several% in a mixing pulverization or granulation step, and specifically, It may fluctuate by about 3%. That is, the stoichiometric composition may fluctuate due to variations in the manufacturing method.

  In order to cope with such compositional fluctuations in the manufacturing process, the compositional ratio of the piezoelectric ceramic composition after firing is increased by ± several%, more specifically ± 3 to 5 by intentionally changing the composition ratio. %. This is the same for, for example, the conventional zirconate titanate (PZT), and the mixing ratio is adjusted in consideration of the evaporation of lead during firing and the incorporation of zirconia from zirconia balls as grinding media. be able to.

In the piezoelectric ceramic composition of the present invention, electrical characteristics such as piezoelectric characteristics do not significantly change even if the composition ratio is intentionally changed as described above.
Accordingly, in the present invention, the general formula _{Li x (K 1-y Na} y) 1-x} (Nb 1-zw Ta z Sb w) compound represented by O _3, this a perovskite structure formula When applied to ABO ₃ , the composition ratio of A-site atoms and B-site atoms can be shifted to about ± 5 mol% with respect to 1: 1. In order to reduce lattice defects in the formed crystal and obtain high electrical characteristics, the composition is preferably up to about ± 3%.
That is, the general compound of formula as the main component of the piezoelectric ceramic _{composition, [Li x (K 1-} y Na y) 1-x] a {(Nb 1-zw Ta z Sb w)} _b O ₃ (0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.95 ≦ a, b ≦ 1.05) Including. Further, as described above, in the above equation, the range of a and b is preferably 0.97 ≦ a, b ≦ 1.03.

Similarly, the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) range of x of O ₃ is preferably 0 <x ≦ 0.2 .
In this case, since Li is an essential component, the piezoelectric ceramic composition can be more easily fired at the time of its production, further improve the piezoelectric characteristics, and further increase the Curie temperature Tc. Can be. This is because by making Li an essential component within the above range, the firing temperature is lowered, and Li plays the role of a firing aid, enabling firing with few voids.

The value of x in the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3 can be the x = 0.
In this case, the general formula is represented by _{(K 1-y Na y)} (Nb 1-zw Ta z Sb w) O 3. In this case, when preparing the piezoelectric ceramic composition, since the raw material does not include a compound containing the lightest Li such as LiCO ₃ , the raw materials are mixed and the piezoelectric ceramic is mixed. Variations in characteristics due to segregation of the raw material powder when producing the composition can be reduced. In this case, a high relative dielectric constant and a relatively large piezoelectric g constant can be realized.

  In the first invention (Claim 1), the piezoelectric ceramic composition contains at least one metal element selected from Mg, Ca, Sr, and Ba as an additional element. The total content of the elements is 0.0001 mol to 0.10 mol per 1 mol of the compound represented by the above general formula. The piezoelectric ceramic composition may contain the above-mentioned additive element by being added to the compound represented by the above-described general formula by substitution, or by being externally added to the compound represented by the above-mentioned general formula. May be contained.

The total content of the additional element, if less than 0.0001 mol, or if more than the 0.10 mol, the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition, the electromechanical coupling factor Kp, relative dielectric constant epsilon _33T / ε _{0 and the} like may be reduced, and a piezoelectric ceramic composition having desired piezoelectric and dielectric properties may not be obtained.
The content of the additional element is the number of moles of each metal element of Mg, Ca, Sr, and Ba.

Further, the additive element, Li of the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3 compound represented by, K, at least the Na It is possible to adopt a form in which a part is replaced with one or more metal elements selected from Mg, Ca, Sr, and Ba. Atoms that can become +2 valent, such as Mg, Ca, Sr, and Ba, are easily replaced by at least a part of Li, K, and Na of the compound represented by the general formula.
On the other hand, the additive element may be in the form of a metal element or a compound containing the metal element, such as an oxide or a perovskite structure compound, which is present in a grain or a grain boundary of the piezoelectric ceramic composition.

Preferably, the additive element is contained by replacing at least a part of Li, K, and Na of the compound represented by the general formula (claim 2).
In this case, it is possible to improve the piezoelectric d ₃₁ constant and piezoelectric characteristics such as electromechanical coupling factor Kp of the piezoelectric ceramic composition, and the relative dielectric constant ε _33T / ε ₀ the dielectric characteristics such as even.

Particularly preferably, one or more metal elements selected from Mg, Ca, Sr, and Ba as the additional elements are substituted for at least a part of K and / or Na of the compound represented by the general formula, the piezoelectric ceramic composition has the general formula _{{Li x (K 1-y} Na y) 1-x-2u Ma u} (Nb 1-zw Ta z Sb w) O 3 ( where, Ma is Mg, Ca, Sr , Ba, x, y, z, w, u are respectively 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, 0.0005 ≦ u ≦ 0.1).
In this case, the piezoelectric properties of the piezoelectric ceramic composition such as the piezoelectric d ₃₁ constant and the electromechanical coupling coefficient Kp, and the dielectric properties such as the relative dielectric constant ε _33T / ε ₀ can be further improved.

  Further, in the second invention (claim 3), the piezoelectric ceramic composition contains, as an additive element, at least one metal element selected from Si, In, and Sc. The total content is 0.08 mol or less per 1 mol of the compound represented by the above general formula. The piezoelectric ceramic composition may contain the above-mentioned additive element by being added to the compound represented by the above-described general formula by substitution, or by being externally added to the compound represented by the above-mentioned general formula. May be contained.

If the total content of the additional elements exceeds 0.08 mol, the piezoelectric properties of the piezoelectric ceramic composition such as the piezoelectric d ₃₁ constant and the electromechanical coupling coefficient Kp, and the relative permittivity ε _33T / ε ₀ etc. Of the piezoelectric ceramic composition may not be obtained, and a piezoelectric ceramic composition having desired piezoelectric and dielectric properties may not be obtained.
The total content of the additional elements is preferably 0.0001 mol or more based on 1 mol of the compound represented by the general formula (claim 4).
In this case, the effect of the above-mentioned additional element can be sufficiently obtained.
The content of the additional element is the number of moles of each metal element of Si, In, and Sc.

Furthermore, the additive elements, Nb in the formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3 compound represented by, Ta, at least Sb It is possible to adopt a form in which a part is replaced with any one or more metal elements selected from the above Si, In and Sc. A metal element that can be trivalent or tetravalent, such as Si, In, or Sc, is likely to be substituted with at least a part of Nb, Ta, and Sb of the compound represented by the general formula.

On the other hand, the additive element may be in the form of a metal element or a compound containing the metal element, such as an oxide or a perovskite structure compound, which is present in a grain or a grain boundary of the piezoelectric ceramic composition. That is, the piezoelectric ceramic composition may contain the above-mentioned additive element by being added to the compound represented by the above general formula by substitution. It may be added and contained.
The piezoelectric ceramic composition according to the second aspect of the invention can exhibit excellent piezoelectric properties and dielectric properties regardless of which of the above two forms contains the additional element. .

  Further, in the third invention (claim 5), the piezoelectric ceramic composition contains Bi as an additional element, and the content of the additional element is based on 1 mol of the compound represented by the general formula. And 0.0001 mol to 0.004 mol.

In the above-described third piezoelectric ceramic composition of the present invention, by containing a small amount of Bi of 0.0001Mol～0.004Mol, properties such as piezoelectric d ₃₁ constant is improved.
The total of the content, of less than 0.0001, or if more than the 0.004 mol, the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition, electro-mechanical coupling coefficient Kp, and the relative dielectric constant ε _33T / ε ₀ And the like, there is a possibility that a piezoelectric ceramic composition having desired piezoelectric properties and dielectric properties cannot be obtained.
The content of the additional element is the number of moles of the metal element Bi.

Furthermore, the additive elements, Nb in the formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3 compound represented by, Ta, at least Sb A configuration in which a part is substituted with a Bi atom and arranged can be employed. A metal element that can be trivalent, such as Bi, is easily replaced by at least a part of Nb, Ta, and Sb of the compound represented by the above general formula.
On the other hand, the above-mentioned additive element may be in the form of a Bi atom or a compound containing the same, such as an oxide or a perovskite structure compound, which is present in a grain or a grain boundary of the piezoelectric ceramic composition. That is, the piezoelectric ceramic composition may contain the above-mentioned additive element by being added to the compound represented by the above general formula by substitution. It may be added and contained.
The piezoelectric ceramic composition according to the third aspect of the invention can exhibit excellent piezoelectric properties and dielectric properties regardless of which of the above two forms contains the additive element. .

Next, in the first to third invention, the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition is represented by the above general formula, a piezoelectric d ₃₁ constant of the piezoelectric ceramic composition containing no additive element Is also preferably large (claim 6).

"Represented by the above general formula, is larger than the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition containing no additive element" described above and, the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition containing the above additive element This means that it is larger than a piezoelectric ceramic composition having the basic composition of the piezoelectric ceramic composition and not containing the above-mentioned additional elements (hereinafter referred to as a basic piezoelectric ceramic composition as appropriate). coupling factor Kp, piezoelectric g ₃₁ constant, the mechanical quality factor Qm, the dielectric constant is the same for the dielectric loss, and Curie temperature Tc.

  Further, the electromechanical coupling coefficient Kp of the piezoelectric ceramic composition is represented by the general formula, and is preferably larger than the electromechanical coupling coefficient Kp of the piezoelectric ceramic composition not containing the additional element. ).

The piezoelectric g ₃₁ constant of the piezoelectric ceramic composition is represented by the above general formula, is preferably larger than the piezoelectric g ₃₁ constant of the piezoelectric ceramic composition containing no additive element (claim 8).

  Further, the mechanical quality factor Qm of the piezoelectric ceramic composition is preferably larger than the mechanical quality factor Qm of the piezoelectric ceramic composition not represented by the general formula and containing the additive element. ).

The piezoelectric d ₃₁ constant of the piezoelectric ceramic composition, electro-mechanical coupling coefficient Kp, the piezoelectric g ₃₁ constant, the mechanical quality factor Qm, represented by the above general formula, the basic piezoelectric ceramic composition containing no additive element If it is larger than the above, the effects of the above-mentioned additional elements can be sufficiently obtained, and the piezoelectric actuator, piezoelectric filter, piezoelectric vibrator, piezoelectric transformer, piezoelectric ultrasonic motor, piezoelectric gyro sensor, knock sensor, yaw rate sensor, air Application to piezoelectric elements such as bag sensors, back sonars, corner sonars, piezoelectric buzzers, piezoelectric speakers, and piezoelectric igniters becomes easier.

Next, the relative dielectric constant of the piezoelectric ceramic composition is preferably larger than the relative dielectric constant of the piezoelectric ceramic composition represented by the general formula and not containing the additional element (claim 10).
When the relative dielectric constant of the piezoelectric ceramic composition (basic piezoelectric ceramic composition) which is represented by the above general formula and does not contain the above-mentioned additive element is smaller than the above, the effect of the above-mentioned additive element cannot be sufficiently obtained. However, there is a possibility that application to a dielectric element such as a capacitor becomes difficult.

Next, it is preferable that the dielectric loss of the piezoelectric ceramic composition is represented by the general formula and is smaller than the dielectric loss of the piezoelectric ceramic composition not containing the additional element.
When the dielectric loss of the piezoelectric ceramic composition (basic piezoelectric ceramic composition) which is represented by the above general formula and does not contain the additive element is larger than the dielectric loss, the effect of the additive element cannot be sufficiently obtained. Therefore, application to a dielectric element such as a capacitor may be difficult.

Next, it is preferable that the Curie temperature Tc of the piezoelectric ceramic composition is represented by the general formula and is higher than the Curie temperature Tc of the piezoelectric ceramic composition not containing the additional element.
When the temperature is higher than the Curie temperature of the piezoelectric ceramic composition represented by the general formula and not containing the additive element (basic piezoelectric ceramic composition), the effect of the additive element can be sufficiently obtained. It is easier to use in an environment with a high temperature exceeding 100 ° C., such as near an engine of a car.

Next, the piezoelectric ceramic composition preferably has a piezoelectric d ₃₁ constant of 30 pm / V or more (claim 13).
In this case, a piezoelectric actuator, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, a piezoelectric ultrasonic motor, a piezoelectric gyro sensor, and a knock sensor are used to take advantage of the piezoelectric d ₃₁ constant as high as 30 pm / V or more. It can be used as a yaw rate sensor, airbag sensor, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter, and the like.
Above for the piezoelectric d ₃₁ constant is less than 30 Pm/V, it may not be used as a piezoelectric element sufficiently endure characteristics for practical use.

Further, in order to obtain a piezoelectric sensor characteristics or larger piezoelectric actuator characteristics more excellent in sensitivity, it is more preferable that the piezoelectric d ₃₁ constant is 40 Pm/V more. More preferably, it is 80 pm / V or more. Still more preferably, it is 100 pm / V or more.

Next, the piezoelectric ceramic composition preferably has an electromechanical coupling coefficient Kp of 0.30 or more.
In this case, utilizing the high electromechanical coupling coefficient Kp of 0.30 or more, the piezoelectric ceramic composition can be converted into a piezoelectric actuator, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, It can be used as a piezoelectric ultrasonic motor, piezoelectric gyro sensor, knock sensor, yaw rate sensor, airbag sensor, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter, and the like.

When the electromechanical coupling coefficient Kp is less than 0.30, there is a possibility that the piezoelectric ceramic composition cannot be used for a piezoelectric element requiring excellent conversion efficiency between the mechanical energy and the electric energy. .
In order to obtain a more excellent conversion efficiency between mechanical energy and electric energy, the electromechanical coupling coefficient Kp is more preferably 0.34 or more. More preferably, it is 0.4 or more. Still more preferably, it is 0.45 or more.

Next, the piezoelectric ceramic composition preferably has a piezoelectric g ₃₁ constant of 7 × 10 ⁻³ Vm / N or more (claim 15).
In this case, the piezoelectric ceramic composition is used as a piezoelectric transformer, an ultrasonic motor element, a sensor element, and the like having an excellent step-up ratio by utilizing the high piezoelectric g ₃₁ constant of 7 × 10 ⁻³ Vm / N or more. be able to.

If the piezoelectric g ₃₁ constant is less than 7 × 10 ⁻³ Vm / N, the piezoelectric ceramic composition may not be able to be used for a piezoelectric element requiring an excellent boost ratio.
Further, in order to obtain a more excellent step-up ratio, the piezoelectric g ₃₁ constant is more preferably 8 × 10 ⁻³ Vm / N or more.

Next, the piezoelectric ceramic composition preferably has a mechanical quality factor Qm of 50 or more.
In this case, taking advantage of the high mechanical quality factor Qm of 50 or more, the piezoelectric ceramic composition can be converted into a piezoelectric element that generates less heat and has excellent conversion efficiency between electric energy and mechanical energy, such as a piezoelectric actuator, a piezoelectric filter, and the like. It can be used as a piezoelectric vibrator, piezoelectric transformer, piezoelectric ultrasonic motor, piezoelectric gyro sensor, knock sensor, yaw rate sensor, airbag sensor, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter, and the like.

When the mechanical quality factor Qm is less than 50, there is a possibility that the piezoelectric ceramic composition cannot be used for a piezoelectric element requiring excellent conversion efficiency between the mechanical energy and the electric energy.
In order to obtain a more excellent conversion efficiency between mechanical energy and electric energy, the mechanical quality factor Qm is more preferably 40 or more. More preferably, it is 50 or more.

Next, the piezoelectric ceramic composition preferably has a relative dielectric constant of 400 or more (claim 7).
In this case, the piezoelectric ceramic composition can be used as a dielectric element such as a capacitor having a large capacitance by utilizing a high relative dielectric constant of 400 or more.

If the relative dielectric constant is less than 400, the capacitance may decrease, and the piezoelectric ceramic composition may not be used as a dielectric element such as a capacitor.
Further, the relative permittivity is preferably 430 or more. More preferably, it is 600 or more.

Next, the piezoelectric ceramic composition preferably has a dielectric loss of 0.09 or less (claim 18).
In this case, the piezoelectric ceramic composition can be converted to a dielectric element such as a capacitor, a piezoelectric actuator, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, a piezoelectric ultrasonic motor, and a piezoelectric gyro sensor by utilizing a low dielectric loss of 0.09 or less. , Knock sensors, yaw rate sensors, airbag sensors, back sonars, corner sonars, piezoelectric buzzers, piezoelectric speakers, and piezoelectric igniters.

  When the dielectric loss exceeds 0.09, the piezoelectric ceramic composition may not be used as a dielectric element such as a capacitor, a piezoelectric transformer element, an ultrasonic motor element, or the like. Therefore, more preferably, the dielectric loss is 0.035 or less. More preferably, it is 0.03 or less.

Next, the piezoelectric ceramic composition preferably has a Curie temperature Tc of 200 ° C. or higher (Claim 19).
In this case, by utilizing the high Curie temperature Tc of 200 ° C. or more, the piezoelectric ceramic composition can be used in a high temperature environment exceeding 100 ° C., for example, near an engine of an automobile.
When the Curie temperature Tc is lower than 200 ° C., when the piezoelectric ceramic composition is used in a high temperature place, for example, near the engine of an automobile, its properties such as a piezoelectric d ₃₁ constant and an electromechanical coupling coefficient Kp are deteriorated. There is a possibility that. Therefore, it is more preferable that the Curie temperature Tc is 250 ° C. or higher.

Next, the piezoelectric ceramic composition preferably has a piezoelectric d ₃₁ constant of 30 pm / V or more and a Curie temperature Tc of 200 ° C. or more (claim 20).
In this case, the piezoelectric ceramic composition can be used as a highly sensitive sensor element, ultrasonic motor element, actuator element, piezoelectric transformer element, piezoelectric vibrator, and the like under a high temperature environment exceeding 100 ° C. .
In order to obtain an excellent piezoelectric sensor characteristic or a larger piezoelectric actuator characteristics of more sensitive, it is preferable that the piezoelectric d ₃₁ constant is 40 Pm/V more. More preferably, it is 80 pm / V or more. Still more preferably, the piezoelectric d ₃₁ constant is preferably 100 pm / V or more.
Further, the Curie temperature Tc is more preferably 250 ° C. or higher.

Next, the piezoelectric ceramic composition preferably has a piezoelectric g ₃₁ constant of 7 × 10 ⁻³ Vm / N or more and a Curie temperature Tc of 200 ° C. or more.
In this case, the piezoelectric ceramic composition can be used as a piezoelectric transformer, an ultrasonic motor element, a sensor element, or the like having an excellent step-up ratio under a high temperature environment exceeding 100 ° C.
Further, in order to obtain a more excellent boost ratio, the piezoelectric g ₃₁ constant is more preferably 8 × 10 ⁻³ Vm / N or more.
Further, the Curie temperature Tc is more preferably 250 ° C. or higher.

Next, it is preferable that the piezoelectric ceramic composition has an electromechanical coupling coefficient Kp of 0.3 or more and a Curie temperature Tc of 200 ° C. or more (claim 22).
In this case, in a high temperature environment exceeding a temperature of 100 ° C., the piezoelectric ceramic composition can be converted into a piezoelectric actuator element, a piezoelectric vibrator, a sensor element, a piezoelectric transformer element, an ultrasonic wave element having excellent conversion efficiency between mechanical energy and electric energy. It can be used as a motor element or the like.
In order to obtain a more excellent conversion efficiency between mechanical energy and electric energy, the electromechanical coupling coefficient Kp is more preferably 0.34 or more. More preferably, it is 0.4 or more.
Further, the Curie temperature Tc is more preferably 250 ° C. or higher.

Next, it is preferable that the piezoelectric ceramic composition has a mechanical quality factor Qm of 50 or more and a Curie temperature Tc of 200 ° C. or more (claim 23).
In this case, in a high-temperature environment exceeding 100 ° C., the piezoelectric ceramic composition is converted into a piezoelectric element, such as a piezoelectric actuator, a piezoelectric filter, or a piezoelectric vibrator, which generates little heat and has excellent conversion efficiency between mechanical energy and electric energy. It can be used as a piezoelectric transformer, piezoelectric ultrasonic motor, piezoelectric gyro sensor, knock sensor, yaw rate sensor, airbag sensor, back sonar, corner sonar, piezoelectric buzzer, piezoelectric speaker, piezoelectric igniter, and the like.
In order to obtain a more excellent conversion efficiency between mechanical energy and electric energy, the mechanical quality factor Qm is more preferably 40 or more. More preferably, it is 50 or more.
Further, the Curie temperature Tc is more preferably 250 ° C. or higher.

Next, it is preferable that the piezoelectric ceramic composition has a dielectric loss of 0.09 or less and a Curie temperature Tc of 200 ° C. or more.
In this case, the piezoelectric ceramic composition can be used as a dielectric element such as a capacitor, a piezoelectric transformer element, an ultrasonic motor element, a sensor element, and the like under a high temperature environment exceeding 100 ° C.
More preferably, the dielectric loss is 0.035 or less. More preferably, it is 0.03 or less.
Further, the Curie temperature Tc is more preferably 250 ° C. or higher.

Next, the piezoelectric ceramic composition preferably has a piezoelectric d ₃₁ constant of 30 pm / V or more, an electromechanical coupling coefficient Kp of 0.3 or more, and a Curie temperature Tc of 200 ° C. or more. 25).
In this case, the piezoelectric ceramic composition can be used in a high-temperature environment exceeding 100 ° C., and can have excellent sensitivity and conversion efficiency between mechanical energy and electric energy.
Further, more excellent piezoelectric sensor characteristics of sensitivity, or to obtain a larger piezoelectric actuator characteristics, it is more preferable that the piezoelectric d ₃₁ constant is 40 Pm/V more. Further, the electromechanical coupling coefficient Kp is more preferably 0.34 or more.

Further, in the fourth (invention 26) or the seventh invention (invention 29), as the additive, any one or more metal elements selected from Mg, Ca, Sr, and Ba, or these metal elements There are compounds containing elements.
The above additives, as an additive element of the metallic element contained in the additive formula after the burning _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O _The compound represented by ₃ may be contained in the piezoelectric ceramic composition by replacing at least a part of Li, K, and Na. Further, the metal element or a compound containing the metal element, such as an oxide or a perovskite structure compound, may be contained in the piezoelectric ceramic composition in a grain or a grain boundary.

Further, in the fifth (invention 27) or the eighth invention (invention 31), as the additive, any one or more metal elements selected from Si, In, and Sc, or these metal elements can be used. And the like.
The above additives, as an additive element of the metallic element contained in the additive formula after the burning _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O _The compound represented by ₃ may be contained in the piezoelectric ceramic composition by substituting at least a part of Nb, Ta, and Sb for the compound. Further, the metal element or a compound containing the metal element, such as an oxide or a perovskite structure compound, may be contained in the piezoelectric ceramic composition in a grain or a grain boundary.

In the sixth (invention 28) or the ninth invention (invention 33), the additive includes a Bi atom or a compound containing a Bi atom.
The above additives, as an additive element of Bi contained in the additive formula after the firing at _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3 In some cases, at least a part of Nb, Ta, and Sb of the represented compound is substituted and contained in the piezoelectric ceramic composition. In addition, as the compound such as the Bi atom or the oxide or the perovskite structure compound containing the Bi atom, it may be contained in the inside of the grain or the grain boundary in the piezoelectric ceramic composition.

Next, in the seventh to ninth inventions, examples of the compound containing lithium include, for example, Li ₂ CO ₃ , Li ₂ O, LiNO ₃ , and LiOH. The sodium-containing compounds include Na ₂ CO ₃ , NaHCO ₃ and NaNO ₃ .

Examples of the potassium-containing compound include K ₂ CO ₃ , KNO ₃ , KNbO ₃ , and KTaO ₃ . Examples of the compound containing the above-mentioned niobium, for example _{Nb 2 O 5, Nb 2 O} 3, there is NbO ₂ and the like. Examples of the tantalum-containing compound include Ta ₂ O ₅ . Examples of the compound containing the above antimony, for example, a _{Sb 2 O 5, Sb 2 O} 3, Sb 2 O 4 or the like.

Next, in the seventh invention (claim 29), the compound containing Li is Li ₂ CO ₃ , the compound containing Na is Na ₂ CO ₃ , and the compound containing K is K ₂ CO _3. , The compound containing Nb is Nb ₂ O ₅ , the compound containing Ta is Ta ₂ O ₅ , the compound containing Sb is Sb ₂ O ₅ or Sb ₂ O ₃ , the additive is MgO, MgCO ₃ , CaO, CaCO ₃ , SrO, SrCO ₃ , BaO, and BaCO ₃ (claim 30).
In this case, the piezoelectric ceramic composition of the first invention can be easily produced.

In the eighth invention (claim 31), the compound containing Li is Li ₂ CO ₃ , the compound containing Na is Na ₂ CO ₃ , the compound containing K is K ₂ CO ₃ , The compound containing Nb is Nb ₂ O ₅ , the compound containing Ta is Ta ₂ O ₅ , the compound containing Sb is Sb ₂ O ₅ or Sb ₂ O ₃ , and the additive is SiO ₂ or In _2. O _3, and it is preferable that any one or more selected from Sc ₂ O ₃ (claim 32).
In this case, the piezoelectric ceramic composition of the second invention can be easily produced.

In the ninth invention (claim 33), the compound containing Li is Li ₂ CO ₃ , the compound containing Na is Na ₂ CO ₃ , the compound containing K is K ₂ CO ₃ , The compound containing Nb is Nb ₂ O ₅ , the compound containing Ta is Ta ₂ O ₅ , the compound containing Sb is Sb ₂ O ₅ or Sb ₂ O ₃ , and the additive is Bi ₂ O ₃ . It is preferable (claim 34).
In this case, the piezoelectric ceramic composition of the third invention can be easily produced.

  Next, in the tenth (claim 35) or the eleventh invention (claim 36), the piezoelectric element may be, for example, a piezoelectric actuator, a piezoelectric filter, a piezoelectric vibrator, a piezoelectric transformer, a piezoelectric ultrasonic motor, a piezoelectric gyro. There are sensors, knock sensors, yaw rate sensors, airbag sensors, back sonars, corner sonars, piezoelectric buzzers, piezoelectric speakers, and piezoelectric igniters.

  Next, in the twelfth aspect (claim 37) or the thirteenth aspect (claim 38), examples of the dielectric element include a capacitor and a multilayer capacitor.

(Example 1)
Next, a piezoelectric ceramic composition according to an example of the present invention will be described.
In this example, the piezoelectric ceramic composition of the first invention (claim 1) is manufactured and its characteristics are measured.
The piezoelectric ceramic composition of this example is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w Are piezoelectric ceramic compositions containing, as main components, compounds having composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2, respectively. The piezoelectric ceramic composition contains at least one metal element selected from Mg, Ca, Sr, and Ba as an additive element. The total content of the additional elements is 0.01 mol based on 1 mol of the compound represented by the general formula.

The method for producing the piezoelectric ceramic composition of the present example comprises a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb. with a compound of the general formula after calcination _{{Li x (K 1-y} Na y) 1-x} is represented by _{(Nb 1-zw Ta z Sb} w) O 3, and x, y, z, w, respectively It is prepared in a stoichiometric ratio so as to be a compound in a composition range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2. And an additive containing at least one metal element selected from Ca, Sr, and Ba.

Hereinafter, the method for producing the piezoelectric ceramic composition of the present example will be described in detail.
First, as raw materials of the basic composition of the piezoelectric ceramic composition, high-purity Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Sb ₂ O _{5 with} a purity of 99% or more. And CaO, SrO, MgO, and BaO as the above additives were prepared.

Of these raw materials, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , and Sb ₂ O ₅ are fired, and after firing, the above general formula {Li _x (K _{1-y) Na y) 1-x} (} Nb 1-zw Ta z Sb w) at _{O 3, x, y, z} , w , respectively x = 0.04, y = 0.5, z = 0.1, w = 0.04, that is, the stoichiometric ratio is such that the above general formula is {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _3. Then, CaO, SrO, MgO or BaO as the above-mentioned additives were respectively blended to obtain eight kinds of blends.

Regarding the compounding amount of the above-mentioned additive, 1 mol of compound {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _3, which is expected to be obtained after baking with the above stoichiometric ratio In addition, 0.01 mol and 0.005 mol of CaO, SrO, MgO, or BaO, respectively, as the above-mentioned additives were blended. At this time, the compounding amount of the metal element of each additive is also 0.01 mol and 0.005 mol.
In addition, among the above-mentioned additives, for CaO, a compound was further prepared by mixing 0.02 mol, 0.04 mol, and 0.10 mol, respectively.
Then, each of the above compounds was mixed in acetone by a ball mill for 24 hours to prepare a mixture.

Next, each of the mixtures was calcined at 750 ° C. for 5 hours, and then each of the calcined mixtures was ground with a ball mill for 24 hours. Subsequently, polyvinyl butyral was added as a binder and granulated.
Each of the granulated powders is pressed at a pressure of ² ton / cm ² into a disc having a diameter of 13 mm and a thickness of 2 mm, and the obtained compact is fired at a temperature of 1000 to 1300 ° C. for 1 hour. Was prepared. The specific firing temperature at this time was selected from the above-mentioned temperature range of 1000 ° C. to 1300 ° C. at which a fired body having the maximum density can be obtained by firing for one hour. At this time, all of the fired bodies were densified to a relative density of 98% or more.

Next, both sides of each fired body were polished in parallel and circularly polished, and then gold electrodes were provided on both sides of the disk sample by sputtering. Then, a DC voltage of 1 to 5 kV / mm was applied between the electrodes in a silicone oil at 100 ° C. for 10 minutes to polarize in the thickness direction to obtain a piezoelectric ceramic composition.
Thus, eleven kinds of piezoelectric ceramic compositions (samples E1 to E4, samples F1 to F4, and samples G1 to G3) were produced. Table 1 shows the mixing ratio of the raw materials and additives in each sample.
Each of the above samples was prepared by a method in which a metal element was substituted for K and Na in a compound represented by {Li _0.04 (K _0.5 Na _0.5 ) _0.95 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ . . That is, for example, in the sample E1, the composition was set to {Li _0.04 (K _0.5 Na _0.5 ) _0.94 Ca _0.01 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ .

In addition, as a method different from the production method of this example, a compound represented by the above {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ is produced by firing, and this is pulverized. Even if the mixture is mixed with the above-mentioned additives and then calcined, granulated, formed and fired in the same manner as in the production method of this example, the same results as those of the above-mentioned samples E1 to E4, F1 to F4 and G1 to G3 are obtained. A piezoelectric ceramic composition can be produced.

In the samples E1 to E4, the samples F1 to F4, and the samples G1 to G3 manufactured in the present example, CaO, SrO, MgO, or BaO as the above-mentioned additive is partially an oxide or a perovskite structure compound. As a compound, the compound is contained in the grains or grain boundaries of each piezoelectric ceramic composition, and a part of the compound is represented by the above {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ It is considered that at least a part of Li, K, and Na contained Ca, Sr, Mg, or Ba atoms in each additive in a state of being substituted.

Next, in this example, in order to clarify the excellent characteristics of the piezoelectric ceramic composition, comparative products (sample C1 and sample C2) were prepared as follows.
First, high-purity Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , and Sb ₂ O ₅ having a purity of 99% or more were prepared as raw materials of comparative products.

These raw materials among _{K 2 CO 3, Na 2 CO} 3, and Nb and ₂ O _5, the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O ₃ , the stoichiometric ratio is such that x = z = w = 0 and y = 0.5, that is, the stoichiometric ratio is such that the above general formula is (K _0.5 Na _0.5 ) NbO _3. Then, the mixture was mixed in acetone by a ball mill for 24 hours to obtain a mixture.
This mixture was calcined, granulated, molded, fired, and polarized in the same manner as in Samples E1 to E4, Samples F1 to F4, and Samples G1 to G3 to obtain a piezoelectric ceramic composition (Sample C1) was prepared.
Sample C1 is a piezoelectric ceramic composition containing (K _0.5 Na _0.5 ) NbO ₃ .

Next, the sample C2 is manufactured as follows.
First, the raw materials Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , and Sb ₂ O ₅ prepared above are calcined, and after firing, the above general formula {Li _x ( in _{K 1-y Na y) 1} -x} (Nb 1-zw Ta z Sb w) O 3, x = 0.04, y = 0.5, and z = 0.1 and w = 0.04, At a stoichiometric ratio such that the general formula becomes a compound represented by {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ . The mixture was mixed in a ball mill for 24 hours in acetone to obtain a mixture.

This mixture was calcined, granulated, molded, fired, and polarized in the same manner as in Samples E1 to E4, Samples F1 to F4, and Samples G1 to G3 to obtain a piezoelectric ceramic composition (Sample C2) was prepared.
The sample C2 contains the compound {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ as a main component, similarly to the samples E1 to E4, the samples F1 to F4, and the samples G1 to G3. However, on the other hand, the piezoelectric ceramic composition does not contain the above-mentioned additional elements.
Table 1 shows the composition ratio of Sample C1 and Sample C2.

Next, the sample E1 to E4, sample F1 to F4, the sample G1~ sample G3, the sample C1 and sample C2, the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, piezoelectric g ₃₁ constant, the mechanical quality factor Qm, the ratio The dielectric constant ε _33T / ε ₀ , the dielectric loss tan δ, and the Curie temperature Tc were measured.

The piezoelectric d ₃₁ constant, the piezoelectric g ₃₁ constant, electromechanical coupling factor Kp and mechanical quality factor Qm, the resonance using an impedance analyzer (Agilent Inc. Precision Impedance Analyzer 4294A) - was measured by anti-resonance method.
The dielectric loss tan δ and the relative permittivity ε _33T / ε ₀ were measured at a measurement frequency of 1 kHz using the same impedance analyzer as described above.
The Curie temperature Tc is defined as the temperature at which the relative dielectric constant ε _33T / ε ₀ is the highest.
Table 2 shows the results.

As can be understood from Table 2, the sample E1~ sample E4 and sample F1~ samples F4 and sample G1~ sample G3, compared to sample C1, the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, relative dielectric constant epsilon _33T / ε ₀ and dielectric loss tan δ were improved.
Further, the sample E1~ sample E4 and sample F1~ samples F4 and sample G1~ sample G3 is also compared with sample C2, the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, piezoelectric g ₃₁ constant, the mechanical quality factor Any one or more of Qm, relative permittivity _{33 33T} / ε ₀ , dielectric loss tan δ, and Curie temperature Tc had excellent characteristics equal to or more than one.
Table 2 shows the effect when only CaO is added in an amount of 0.02 mol or more. Although not explicitly shown in Table 2, it has been confirmed that the same effect as that of Ca can be obtained for other additive elements (Mg, Sr, Ba).

Here, paying attention to the piezoelectric d ₃₁ constant, as can be seen from Table 2, the piezoelectric d ₃₁ constant of the sample F2 showed the highest value of 121.0 pm / V.

In the case of using the charge detection type circuit or a current detection type circuit is generally the piezoelectric d ₃₁ constant, the acceleration sensor, weighting sensor, is proportional to the output voltage of the piezoelectric type sensor, such as an impact sensor and the knock sensor. Viewed from that point, it is possible to piezoelectric d ₃₁ constant make a big sensor element of the charge sensor output higher piezoelectric ceramic composition. Then, in making a sensor element having a sample C1 least equivalent properties as a comparative product, it would be preferable to have a piezoelectric d ₃₁ constant over at least 30 pm/V. To generate a highly sensitive sensor element is further enhanced signal-to-noise ratio (SN ratio) and the output voltage, the piezoelectric d ₃₁ constant good not less than 80 pm/V. More preferably, it is 100 pm / V or more.

When used as actuators, generally the piezoelectric d ₃₁ constant is proportional to the generated distortion or displacement of the piezoelectric actuator. Viewed from that point, it is possible to piezoelectric d ₃₁ constant make a big actuator element of higher piezoelectric ceramic composition generates distortion or displacement. And making the actuator element having a comparative product equal or characteristics, it would be preferable to have a piezoelectric d ₃₁ constant over at least 30 pm/V. More preferably, it is 40 pm / V or more. To further prepare the large actuator displacement amount, the piezoelectric d ₃₁ constant good not less than 80 pm/V. More preferably, it is 100 pm / V or more.

  Further, focusing on the electromechanical coupling coefficient Kp, as known from Table 2, the electromechanical coupling coefficient Kp of the sample F2 showed the highest value of 0.551.

  Generally, the electromechanical coupling coefficient Kp is proportional to the electromechanical energy conversion efficiency of a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic vibrator. From that point, a piezoelectric ceramic composition having a higher electromechanical coupling coefficient Kp can produce a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic transducer having higher electromechanical energy conversion efficiency. In order to manufacture a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic vibrator having characteristics equal to or higher than that of the sample C1, which is a comparative product, an electromechanical coupling coefficient Kp of at least 0.3 or more is required. It can be said that it is preferable to have. More preferably, it is 0.34 or more. More preferably, it is 0.4 or more. It is even more preferably 0.45 or more.

  Further, focusing on the mechanical quality factor Qm, as can be seen from Table 2, the mechanical quality factors Qm of the samples E1 to E4 and the samples G1 to G3 are equal to or superior to those of the samples C1 and C2. The value was shown.

  Generally, the mechanical quality factor Qm is proportional to the electromechanical energy conversion efficiency of a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic vibrator, like the electromechanical coupling coefficient Kp. From that point, a piezoelectric ceramic composition having a higher electromechanical coupling coefficient Kp can produce a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic transducer having higher electromechanical energy conversion efficiency. In order to produce a piezoelectric transformer element, an ultrasonic motor element, an actuator element, or an ultrasonic vibrator having characteristics equal to or higher than that of the sample C1, which is a comparative product, the mechanical quality factor Qm must be at least 50 or more. Is preferable.

Focusing on the Curie temperature Tc, the Curie temperature Tc of each of the samples E1 to E4, the samples F1 to F4, and the samples G1 to G3 has a high value of 200 ° C. or higher. Therefore, the piezoelectric ceramic composition of this example (samples E1 to E4 and samples F1 to F4 and samples G1 to G3) can be used stably for a long time even in a high-temperature portion such as the vicinity of an engine of an automobile. It can be used as high temperature sensor parts such as sensors, actuator parts, ultrasonic motor parts, and the like.
In order to use the sensor component, actuator component, ultrasonic motor component, etc. for high temperature more stably for a long time, the Curie temperature Tc is preferably 200 ° C. or more. More preferably, the temperature is 250 ° C. or higher.

Focusing on the piezoelectric g ₃₁ constant, as can be seen from Table 2, the piezoelectric g ₃₁ constant of the sample F2 showed the highest value of 8.81 × 10 ⁻³ Vm / N.

The piezoelectric g ₃₁ constant is proportional to the output voltage of the piezoelectric sensor, the piezoelectric transformer element, the ultrasonic motor element and the like, like the piezoelectric d ₃₁ constant. Therefore, it is possible to make a large sensor voltage sensor output as the piezoelectric g ₃₁ constant high piezoelectric ceramic composition. Then, to produce a sensor having a comparative product equal or characteristics, it would be preferable to have at least 7 × 10 ^-3 Vm / N or more piezoelectric g ₃₁ constant. More preferably, it is 8 × 10 ⁻³ Vm / N or more.

Moreover, focusing on the dielectric constant ε _33T / ε _0, the relative dielectric constant ε _33T / ε ₀ of the sample E1~E4 and sample F1~F4 and sample G1~ sample G3 takes the very high value of 1300 or more I have.

The relative permittivity ε _33T / ε ₀ is generally proportional to the capacitance of a capacitor such as a multilayer capacitor component. From this viewpoint, a piezoelectric ceramic composition having a higher relative dielectric constant can produce a capacitor having a larger capacitance. In order to manufacture a capacitor, it can be said that it is preferable to have a dielectric constant of at least 400 or more. Further, more preferably, 430 or more are preferable. More preferably, it should be 1000 or more.

  Focusing on the dielectric loss tan δ, the dielectric loss tan δ of the samples E1 to E4, the samples F1 to F4, and the samples G1 to G3 has a very low value of 0.034 or less.

  The above-mentioned dielectric loss is proportional to the heat energy lost by applying an AC voltage to components such as a capacitor such as a capacitor component, a piezoelectric ultrasonic motor, a piezoelectric actuator, and a piezoelectric transformer. From this point of view, a piezoelectric ceramic composition having a smaller dielectric loss can produce a capacitor having a smaller energy loss and a piezoelectric ultrasonic motor, a piezoelectric actuator, and a piezoelectric transformer having a smaller heat generation. In order to produce the above-described component having a small energy loss, the component preferably has a dielectric loss of 0.09 or less. More preferably, it is 0.035 or less. More preferably, it is 0.03 or less.

  As described above, the piezoelectric ceramic composition of this example (Samples E1 to E4 and Samples F1 to F4 and Samples G1 to G3) does not contain lead in the composition, and has excellent piezoelectric properties and It has dielectric properties. Therefore, it can be used for a piezoelectric element and a dielectric element which are safe for the environment and have high performance.

(Example 2)
In this example, the piezoelectric ceramic composition of the second invention (claim 4) is manufactured and its characteristics are measured.
The piezoelectric ceramic composition of this example is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w Are piezoelectric ceramic compositions containing, as main components, compounds having composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2, respectively. The piezoelectric ceramic composition contains, as an additive element, at least one metal element selected from Si, In, and Sc. The total content of the additional elements is 0.01 mol based on 1 mol of the compound represented by the general formula.

The method for producing the piezoelectric ceramic composition of the present example comprises a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb. with a compound of the general formula after calcination _{{Li x (K 1-y} Na y) 1-x} is represented by _{(Nb 1-zw Ta z Sb} w) O 3, and x, y, z, w, respectively The compounds are prepared in a stoichiometric ratio such that the compounds fall within the composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2. An additive containing at least one metal element selected from the group consisting of, In and Sc is mixed and fired.

Hereinafter, a method for producing the piezoelectric ceramic composition of the present example will be described.
First, as raw materials of the basic composition of the piezoelectric ceramic composition, high-purity Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Sb ₂ O _{5 with} a purity of 99% or more. And SiO ₂ , Sc ₂ O ₃ , and In ₂ O ₃ as the above additives were prepared.

Of these raw materials, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , and Sb ₂ O ₅ are fired, and after firing, the above general formula {Li _x (K _{1-y) Na y) 1-x} (} Nb 1-zw Ta z Sb w) at _{O 3, x, y, z} , w , respectively x = 0.04, y = 0.5, z = 0.1, w = 0.04, that is, the stoichiometric ratio is such that the above general formula is {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _3. Further, SiO ₂ , Sc ₂ O ₃ , or In ₂ O ₃ as the above additives were blended to obtain three kinds of blends.

Regarding the compounding amount of the above-mentioned additive, 1 mol of compound {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _3, which is expected to be obtained after baking with the above stoichiometric ratio Was mixed with 0.01 mol, 0.005 mol, and 0.005 mol of SiO ₂ , Sc ₂ O ₃ , or In ₂ O ₃ , respectively, as the above additives. That is, the compounding amount of the additive was such that the compounding amounts of Si, Sc, and In as the additive elements were 0.01 mol.

Then, each of the above compounds was mixed in acetone by a ball mill for 24 hours to prepare a mixture.
Next, this mixture was calcined, granulated, molded, fired, and polarized in the same manner as in Samples E1 to E4 of Example 1 to obtain three types of piezoelectric ceramic compositions (Samples E5 to E7). ) Got. Table 3 shows the mixing ratio of the raw materials and additives of each sample.

In addition, as a method different from the production method of this example, a compound represented by the above {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ is produced by firing, and this is pulverized. The same piezoelectric ceramic composition as that of the above-mentioned samples E5 to E7 can be produced by mixing with the above-mentioned additives and thereafter performing calcination, granulation, molding and firing in the same manner as in the production method of this example.

In samples E5 to E7 manufactured in this example, SiO ₂ , Sc ₂ O ₃ , or In ₂ O ₃ as the above-mentioned additive were partially converted into compounds such as oxides or perovskite-structured compounds by using each piezoelectric ceramic. At least one of Nb, Ta, and Sb of the compound represented by {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ contained in the grain boundaries of the composition and partially It is considered that the part contained Si, Sc, or In atoms in each additive in a state of being substituted.

Next, the sample E5～E7, in the same manner as in Example 1, the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, piezoelectric g ₃₁ constant, the mechanical quality factor Qm, the dielectric constant ε _33T / ε _0, dielectric The loss tan δ and the Curie temperature Tc were measured.
Table 4 shows the results. Table 4 also shows various piezoelectric characteristics and dielectric characteristics of Sample C1 and Sample C2 manufactured in Example 1 for comparison.

As can be understood from Table 4, the sample E5~ sample E7, compared to sample C1, the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, relative dielectric constant ε _33T / ε _0, and dielectric loss tanδ is not significantly improved Was.
Further, the sample E5~ Sample E7 can be compared to samples C2, the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, piezoelectric g ₃₁ constant, has improved mechanical quality factor Qm, and dielectric loss tanδ is, The relative dielectric constant ε _33T / ε ₀ and the Curie temperature Tc were also equal to or better.
Table 4 shows that a piezoelectric ceramic composition containing 0.01 mol of the above-mentioned additive element has excellent piezoelectric properties. Although not explicitly shown in Table 4, it has been confirmed that the same effect as described above can be obtained even when the content of the additional element is changed in the range of 0.001 to 0.08 mol.

  As described above, the piezoelectric ceramic composition of this example (samples E5 to E7) does not contain lead in the composition and has excellent piezoelectric properties and dielectric properties as described above. Therefore, it can be used for a piezoelectric element and a dielectric element which are safe for the environment and have high performance.

(Example 3)
In this example, the piezoelectric ceramic composition of the third invention (claim 4) is manufactured and its characteristics are measured.
The piezoelectric ceramic composition of this example is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w Are piezoelectric ceramic compositions containing, as main components, compounds having composition ranges of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2, respectively. The piezoelectric ceramic composition contains Bi as an additional element. The content of the additional element is 0.0001 mol to 0.004 mol based on 1 mol of the compound represented by the general formula.

The method for producing the piezoelectric ceramic composition of the present example comprises a compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb. with a compound of the general formula after calcination _{{Li x (K 1-y} Na y) 1-x} is represented by _{(Nb 1-zw Ta z Sb} w) O 3, and x, y, z, w, respectively The compound is prepared in a stoichiometric ratio so as to be a compound having a composition range of 0 ≦ x ≦ 0.2, 0 ≦ y ≦ 1, 0 <z ≦ 0.4, and 0 <w ≦ 0.2. Is mixed and fired.

Hereinafter, a method for producing the piezoelectric ceramic composition of the present example will be described.
First, as raw materials of the basic composition of the piezoelectric ceramic composition, high-purity Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Sb ₂ O _{5 with} a purity of 99% or more. , And Bi ₂ O ₃ as the above additive were prepared.

Of these raw materials, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , and Sb ₂ O ₅ are fired, and after firing, the above general formula {Li _x (K _{1-y) Na y) 1-x} (} Nb 1-zw Ta z Sb w) at _{O 3, x, y, z} , w , respectively x = 0.04, y = 0.5, z = 0.1, w = 0.04, that is, the stoichiometric ratio is such that the above general formula is {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _3. Further, Bi ₂ O ₃ as the above-mentioned additive was blended by changing the amount of addition to obtain four kinds of blends.

Regarding the compounding amount of the above-mentioned additive, 1 mol of compound {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _3, which is expected to be obtained after baking with the above stoichiometric ratio Was mixed with 0.00025 mol, 0.0005 mol, 0.0025 mol, or 0.005 mol of Bi ₂ O ₃ as the above additive. That is, the amount of the additive was adjusted so that bismuth was contained in 0.0005 mol, 0.001 mol, 0.005 mol, or 0.01 mol, respectively.

Then, each of the above compounds was mixed in acetone by a ball mill for 24 hours to prepare a mixture.
Next, this mixture was calcined, granulated, molded, fired, and polarized in the same manner as in Samples E1 to E4 and Samples F1 to F4 in Example 1 described above, and subjected to four types of piezoelectric ceramic compositions ( Samples E8 to E11) were obtained. Table 5 shows the mixing ratio of the raw materials and additives of each sample.

In addition, as a method different from the production method of this example, a compound represented by the above {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O ₃ is produced by firing, and this is pulverized. The same piezoelectric ceramic composition as that of the above-mentioned samples E8 to E11 can be produced by mixing with the above-mentioned additives and thereafter performing calcination, granulation, molding and firing in the same manner as in the production method of this example.

In the samples E8 to E11 manufactured in this example, Bi as the additional element is partially contained as an oxide or a compound such as a perovskite structure compound in the grains or grain boundaries of each piezoelectric ceramic composition. And a part of the compound represented by {Li _0.04 (K _0.5 Na _0.5 ) _0.96 } (Nb _0.86 Ta _0.1 Sb _0.04 ) O _{3, in} which at least a part of Nb, Ta, and Sb is substituted with a Bi atom. It is considered that it is included in the state where it was done.

Next, the sample E8～E11, in the same manner as in Example 1, the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, piezoelectric g ₃₁ constant, the mechanical quality factor Qm, the dielectric constant ε _33T / ε _0, dielectric The loss tan δ and the Curie temperature Tc were measured.
Table 6 shows the results. Table 6 also shows, for comparison, various piezoelectric characteristics and dielectric characteristics of Sample C1 and Sample C2 manufactured in Example 1.

As can be understood from Table 6, the Sample E8 and Sample E9, compared to sample C1, the piezoelectric d ₃₁ constant, electromechanical coupling factor Kp, relative dielectric constant ε _33T / ε _0, and dielectric loss tanδ is significantly improved I was
Further, the sample C8 and E9 can be compared to samples C2, the piezoelectric d ₃₁ constant, and the electromechanical coupling coefficient Kp, and the relative dielectric constant ε _33T / ε ₀ is improved, other properties equal or equivalent It was better than that. And dielectric loss tan [delta piezoelectric g ₃₁ constant, the mechanical quality factor Qm, dielectric loss tan [delta, and the even Curie temperature Tc, exhibited excellent properties equal to or larger than that of the sample C1.

On the other hand, Sample E10, compared to sample C1, the piezoelectric d ₃₁ constant, the dielectric constant ε _33T / ε _0, and dielectric loss tanδ were significantly improved. In addition, the mechanical quality factor Qm and the relative dielectric constant _{33 33T} / ε ₀ were improved as compared with Sample C2. However, on the other hand, the electromechanical coupling coefficient Kp and the piezoelectric g ₃₁ constant were significantly reduced.
Also, the sample E11 has improved mechanical quality factor Qm, relative permittivity ε _33T / ε ₀ and dielectric loss tan δ as compared with sample C1, and the mechanical quality factor Qm is higher than sample C2. On the other hand, the piezoelectric d ₃₁ constant, the electromechanical coupling coefficient Kp, the piezoelectric g ₃₁ constant, and the like were significantly reduced.

  As described above, the piezoelectric ceramic compositions (samples E8 and E9) of the present example do not contain lead in the composition and have excellent piezoelectric properties and dielectric properties as described above. Therefore, it can be used for a piezoelectric element and a dielectric element which are safe for the environment and have high performance.

In addition, in this example, although not specifically stated, it has been confirmed that the effect of the above-mentioned additional element is similarly exhibited even with a content as small as 0.0001 mol. Furthermore, it has been confirmed that the effect of the above-described additive element can be similarly improved in the piezoelectric characteristics regardless of whether the element is replaced or added externally.
Further, in this example, the effect of improving the piezoelectric properties of the piezoelectric ceramic composition containing a compound having a specific composition as a main component was confirmed by the above-described additive element. However, the general formula ΔLi _x (K _1-y Na _y ) for even _{1-x} (Nb 1-} zw Ta z Sb w) piezoelectric ceramic composition composed mainly of other compounds represented by O _3, it was confirmed that can exhibit the same effect.

Claims (38)

It is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2 , 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, a piezoelectric ceramic composition mainly comprising a compound in the composition range,
The piezoelectric ceramic composition contains, as an additive element, at least one metal element selected from Mg, Ca, Sr, and Ba.
A piezoelectric ceramic composition, wherein the total content of the additional elements is 0.0001 mol to 0.10 mol per 1 mol of the compound represented by the general formula.   2. The piezoelectric ceramic composition according to claim 1, wherein the additive element is contained by replacing at least a part of Li, K, and Na of the compound represented by the general formula. It is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2 , 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, a piezoelectric ceramic composition mainly comprising a compound in the composition range,
The piezoelectric ceramic composition contains, as an additive element, at least one metal element selected from Si, In, and Sc.
A piezoelectric ceramic composition, wherein the total content of the additional elements is 0.08 mol or less based on 1 mol of the compound represented by the general formula.   4. The piezoelectric ceramic composition according to claim 3, wherein the total content of the additional elements is 0.0001 mol or more based on 1 mol of the compound represented by the general formula. It is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2 , 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, a piezoelectric ceramic composition mainly comprising a compound in the composition range,
The piezoelectric ceramic composition contains Bi as an additional element,
A piezoelectric ceramic composition, wherein the content of the additional element is 0.0001 mol to 0.004 mol based on 1 mol of the compound represented by the general formula. According to any one of claims 1 to 5, the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition is represented by the above general formula, than the piezoelectric d ₃₁ constant of the piezoelectric ceramic composition containing no additive element , A piezoelectric ceramic composition characterized by being large.   The electromechanical coupling coefficient Kp of the piezoelectric ceramic composition according to any one of claims 1 to 6, wherein the electromechanical coupling coefficient Kp of the piezoelectric ceramic composition is represented by the general formula and does not include the additive element. A piezoelectric ceramic composition characterized by being larger than the above. 8. The piezoelectric g ₃₁ constant of the piezoelectric ceramic composition according to claim 1, wherein the piezoelectric g ₃₁ constant of the piezoelectric ceramic composition is represented by the general formula and is larger than the piezoelectric g ₃₁ constant of the piezoelectric ceramic composition containing no additional element. , A piezoelectric ceramic composition characterized by being large.   The mechanical quality factor Qm of the piezoelectric ceramic composition according to any one of claims 1 to 8, wherein the mechanical quality factor Qm of the piezoelectric ceramic composition is represented by the general formula and does not include the additive element. A piezoelectric ceramic composition characterized by being larger than the above.   The relative dielectric constant of the piezoelectric ceramic composition according to any one of claims 1 to 9, wherein the relative dielectric constant of the piezoelectric ceramic composition is represented by the general formula and is larger than the relative dielectric constant of the piezoelectric ceramic composition not containing the additive element. A piezoelectric ceramic composition comprising:   The dielectric loss of the piezoelectric ceramic composition according to any one of claims 1 to 10, wherein the dielectric loss is represented by the general formula and is smaller than the dielectric loss of the piezoelectric ceramic composition not containing the additional element. Piezoelectric ceramic composition.   The Curie temperature Tc of the piezoelectric ceramic composition according to any one of claims 1 to 11, wherein the Curie temperature Tc of the piezoelectric ceramic composition is represented by the general formula and is higher than the Curie temperature Tc of the piezoelectric ceramic composition not containing the additional element. A piezoelectric ceramic composition comprising: In any one of claims 1 to 12, the piezoelectric ceramic composition, the piezoelectric porcelain composition, wherein the piezoelectric d ₃₁ constant is 30 Pm/V more.   The piezoelectric ceramic composition according to any one of claims 1 to 13, wherein the piezoelectric ceramic composition has an electromechanical coupling coefficient Kp of 0.30 or more. In any one of claims 1 to 14, the piezoelectric ceramic composition, the piezoelectric porcelain composition, wherein the piezoelectric g ₃₁ constant is 7 × 10 ^-3 Vm / N or more.   The piezoelectric ceramic composition according to any one of claims 1 to 15, wherein the piezoelectric ceramic composition has a mechanical quality factor Qm of 50 or more.   The piezoelectric ceramic composition according to any one of claims 1 to 16, wherein the piezoelectric ceramic composition has a relative dielectric constant of 400 or more.   The piezoelectric ceramic composition according to any one of claims 1 to 17, wherein the piezoelectric ceramic composition has a dielectric loss of 0.09 or less.   The piezoelectric ceramic composition according to any one of claims 1 to 18, wherein the piezoelectric ceramic composition has a Curie temperature Tc of 200 ° C or higher. In any one of claims 1 to 12, the piezoelectric ceramic composition, the piezoelectric porcelain composition, wherein the piezoelectric d ₃₁ constant is at 30 Pm/V or more and the Curie temperature Tc is 200 ° C. or higher. 13. The piezoelectric device according to claim 1, wherein the piezoelectric ceramic composition has a piezoelectric g ₃₁ constant of 7 × 10 ⁻³ Vm / N and a Curie temperature Tc of 200 ° C. or more. Porcelain composition.   The piezoelectric ceramic composition according to any one of claims 1 to 12, wherein the piezoelectric ceramic composition has an electromechanical coupling coefficient Kp of 0.3 or more and a Curie temperature Tc of 200 ° C or more. .   The piezoelectric ceramic composition according to any one of claims 1 to 12, wherein the piezoelectric ceramic composition has a mechanical quality factor Qm of 50 or more and a Curie temperature of 200 or more.   13. The piezoelectric ceramic composition according to claim 1, wherein the piezoelectric ceramic composition has a dielectric loss of 0.09 or less and a Curie temperature Tc of 200 ° C. or more. In any one of claims 1 to 12, the piezoelectric ceramic composition in the piezoelectric d ₃₁ constant 30 Pm/V above, and in electromechanical coupling coefficient Kp is 0.3 or more, and the Curie temperature Tc is 200 ° C. A piezoelectric ceramic composition characterized by the above. It is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2 , 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, and an additive containing at least one metal element selected from Mg, Ca, Sr, and Ba And sintering the mixture. It is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2 , 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, and an additive containing at least one metal element selected from Si, In, and Sc. A method for producing a piezoelectric ceramic composition, comprising mixing and firing. It is represented by the general formula _{{Li x (K 1-y} Na y) 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2 , 0 ≦ y ≦ 1, 0 <z ≦ 0.4, 0 <w ≦ 0.2, and a compound containing Bi and an additive containing Bi are mixed and fired. Method of manufacturing a product. A compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb are fired to obtain a compound of the general formula {Li _x It is represented by _{(K 1-y Na y)} 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2,0 ≦ y ≦ The stoichiometric ratio is such that the compound is in the composition range of 1,0 <z ≦ 0.4 and 0 <w ≦ 0.2, or the substitution with the metal element contained in the following additives is considered. A method for producing a piezoelectric ceramic composition, comprising preparing at a stoichiometric ratio, further mixing an additive containing at least one metal element selected from Mg, Ca, Sr, and Ba, followed by firing. . 30. The compound according to claim 29, wherein the compound containing Li is Li ₂ CO ₃ , the compound containing Na is Na ₂ CO ₃ , the compound containing K is K ₂ CO ₃ , and the compound containing Nb is Nb _2. O ₅ , the compound containing Ta is Ta ₂ O ₅ , the compound containing Sb is Sb ₂ O ₅ or Sb ₂ O ₃ , and the additive is MgO, MgCO ₃ , CaO, CaCO ₃ , SrO, SrCO _3. A method for producing a piezoelectric ceramic composition, comprising at least one selected from the group consisting of BaO, BaO and BaCO ₃ . A compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb are fired to obtain a compound of the general formula {Li _x It is represented by _{(K 1-y Na y)} 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2,0 ≦ y ≦ The stoichiometric ratio is such that the compound is in the composition range of 1,0 <z ≦ 0.4 and 0 <w ≦ 0.2, or the substitution with the metal element contained in the following additives is considered. A method for producing a piezoelectric ceramic composition, comprising preparing a stoichiometric composition, further mixing an additive containing at least one metal element selected from Si, In, and Sc, followed by firing. 32. The compound according to claim 31, wherein the compound containing Li is Li ₂ CO ₃ , the compound containing Na is Na ₂ CO ₃ , the compound containing K is K ₂ CO ₃ , and the compound containing Nb is Nb _2. O ₅ , the Ta-containing compound is Ta ₂ O ₅ , the Sb-containing compound is Sb ₂ O ₅ or Sb ₂ O ₃ , and the additive is SiO ₂ , In ₂ O ₃ , and Sc ₂ O _3. A method for producing a piezoelectric ceramic composition, which is at least one selected from the group consisting of: A compound containing Li, a compound containing Na, a compound containing K, a compound containing Nb, a compound containing Ta, and a compound containing Sb are subjected to a general formula {Li _x It is represented by _{(K 1-y Na y)} 1-x} (Nb 1-zw Ta z Sb w) O 3, and x, y, z, w respectively 0 ≦ x ≦ 0.2,0 ≦ y ≦ At a stoichiometric ratio so as to be a compound in the composition range of 1,0 <z ≦ 0.4 and 0 <w ≦ 0.2, or in consideration of substitution by Bi atoms contained in the following additives. A method for producing a piezoelectric ceramic composition, comprising preparing at a stoichiometric ratio, further mixing an additive containing Bi, and firing. 34. The compound according to claim 33, wherein the compound containing Li is Li ₂ CO ₃ , the compound containing Na is Na ₂ CO ₃ , the compound containing K is K ₂ CO ₃ , and the compound containing Nb is Nb _2. O _5, a piezoelectric ceramic composition, wherein the compound containing the above-mentioned Ta is Ta ₂ O _5, compounds containing the Sb is Sb ₂ O ₅ or Sb ₂ O _3, the additive is Bi ₂ O ₃ Method of manufacturing a product.   A piezoelectric element comprising a piezoelectric body comprising the piezoelectric ceramic composition according to any one of claims 1 to 25.   A piezoelectric element comprising a piezoelectric body made of the piezoelectric ceramic composition manufactured by the manufacturing method according to any one of claims 26 to 34.   A dielectric element comprising a dielectric comprising the piezoelectric ceramic composition according to any one of claims 1 to 25. A dielectric element comprising a dielectric made of the piezoelectric ceramic composition manufactured by the method according to any one of claims 26 to 34.