JPH07112928B2 - Manufacturing method of ceramic raw material powder - Google Patents

Description

The present invention relates to a method for producing a ceramic raw material powder.

[Conventional technology]

Formula containing at least one of Ta and Nb as constituent elements
A ceramic raw material powder represented by ABO ₃ (wherein A represents one or more oxygen 12-coordinated metal elements and B represents one or more oxygen 6-coordinated metal elements, respectively) Piezoelectric materials, optoelectronic materials, dielectric materials, semiconductors,
It is widely used as a raw material for functional ceramics such as sensors. In recent years, with the advancement of these functional ceramics, there has been a demand for raw material powders which can cope with these, have excellent easiness of sintering and uniformity, and have high bulk density and low cost.

Conventionally, the ceramic raw material powder has been manufactured by a dry method or a wet coprecipitation method.

The dry method is a method in which compound powders of the constituents are mixed and calcined. However, with this method, it is difficult to obtain a raw material powder with a uniform composition, and since it is necessary to raise the calcination temperature in order to complete the BZT formation reaction, this causes the particles to become coarse and easy to sinter. There was a drawback that it was hard to become.

Further, regarding the raw materials of Ta and Nb, tantalum oxide and niobium oxide powders conventionally used in the dry method are columbite, tantalite, strobelite, pyrochlore, or ores such as scrap containing Ta and Nb. Dissolved in hydrofluoric acid, Ta and Nb by solvent extraction method and ion exchange method
Is separated and impurities are removed to obtain a high-purity hydrofluoric acid solution, which is neutralized with NH ₄ OH to form a precipitate, which is then filtered,
It is obtained by washing, drying and calcining.

In the dry method, these oxide powders and compound powders of other constituents are mixed and calcined to obtain a ceramic raw material powder represented by ABO ₃ .

The wet coprecipitation method is a method in which a mixed solution of all the constituent components of the target ceramic raw material powder is prepared, and a precipitation forming solution such as an alkali is added to the mixture to coprecipitate, followed by drying and calcination. However, although this method makes it easy to obtain a powder with excellent uniformity, it is difficult to form a secondary particle by condensing to form secondary particles during precipitation formation, drying, and calcination because of its uniformity. There is.

Furthermore, when an aqueous solution of fluoride that is industrially usable as a raw material for niobium and tantalum is used in the wet coprecipitation method, fluorine ions are other constituent ions of the ceramic raw material powder, such as barium, bismuth, lead, strontium, and magnesium. Niobium fluoride and tantalum fluoride cannot be used because they react with and form a precipitate of fluoride. For this reason, there is a problem that a ceramic raw material powder containing Ta and Nb cannot be produced by a wet coprecipitation method with excellent characteristics.

[Problems to be Solved by the Invention]

INDUSTRIAL APPLICABILITY The present invention solves the conventional problems, can use a fluoride that can be industrially easily and advantageously used as a raw material for niobium and tantalum, is easy to sinter, is excellent in uniformity, has a high bulk density, and It is an object of the present invention to provide a method capable of producing a low cost ceramic raw material powder.

[Means for solving problems]

That is, the method for producing a ceramic raw material powder according to the first invention of the present application is based on the formula ABO ₃ containing at least one of Ta and Nb as a constituent element (where A is one of oxygen 12 coordination metal elements or 2 1 or more, and B represents one or more oxygen hexacoordinated metal elements), in producing an aqueous solution of at least one fluoride of Ta and Nb. After the excess precipitate forming liquid is uniformly mixed to form a precipitate, the fluorine ions are removed, and then the aqueous solution in which the precipitate is dispersed and the aqueous solution containing the components A and B other than Ta and Nb are sequentially and uniformly mixed. To form an intimate precipitate of all components, and then the precipitate is calcined at 400 to 1200 ° C.

Further, the method for producing a ceramic raw material powder according to the second invention of the present application is based on the formula ABO ₃ containing at least one of Ta and Nb as a constituent element (where A is one or two kinds of oxygen 12 coordination metal elements). Representing the above, B is one of oxygen hexacoordinated metal elements or 2
Represents more than one species. In producing the ceramic raw material powder shown in), an aqueous solution of at least one fluoride of Ta and Nb is sequentially and uniformly mixed with a precipitation forming liquid in which compound powders of A and B components other than Ta and Nb are dispersed. To form an intimate precipitate of all components, and then the precipitate is calcined at 400 to 1200 ° C.

In order to specifically carry out the first invention of the present application, a dense precipitate can be produced in the order of precipitate formation shown in FIG. 1 (A). In forming the precipitate, Ta and / or Nb is first precipitated by using an aqueous solution of at least one fluoride of Ta and Nb, and then F ⁻ ions in the precipitate dispersion are removed, and then B
Precipitate a, Bi, Pb, Sr, Mg, etc.

In order to specifically implement the second invention of the present application, the first
A tight precipitate can be prepared in the order of precipitate formation shown in FIG. At the time of forming a precipitate, an aqueous solution of at least one fluoride of Ta and Nb is added to a precipitation forming liquid in which compound powders of A and B components other than Ta and Nb (oxides and hydroxides are suitable) are dispersed. Mix to form a precipitate.

Examples of the A component include Ba, Pb, Sr, Ca, and rare earth elements, and B components other than Ta and Nb include B
i, Ti, Zr, Mg, Sc, Hf, Th, W, Cr, Mo, Mn, Fe, C
Examples include o, Ni, Zn, Cd, Al, Sn, As and the like.

The effect of the present invention becomes remarkable especially when Ba, Bi, Pb, Sr, Mg, etc. described above are used as components of the ceramic raw material powder. As a specific example of the ceramic raw material powder produced by the method of the present invention, an example using Ba is represented by the following composition formulas (1) to (3).

Composition formula (1) Ba (Zn _x · Ta _1-x ) O ₃ (where x is a mole fraction and is a number in the range of 0.1 to 0.9. The molar ratio of Ba / (Zn + Ta) is a value near 1.0. Composition formula (2) Ba (Zn _x · Nb _1-x ) O ₃ (where x is a mole fraction and is a number in the range of 0.1 to 0.9. Mo / Ba / (Zn + Nb) molar ratio) Can take a value near 1.0.) Composition formula (3) 3BaO ・ vZnO ・ (1-w) Nb ₂ O ₅・ wTa ₂ O ₅ (where 0.6 ≦ v ≦ 2.0 and 0 <w <1 There are hydroxides, oxychlorides, carbonates, oxynitrates, etc.
Examples thereof include sulfates, nitrates, acetates, fluorides, formates, oxalates, chlorides and oxides. When these are not soluble in water, mineral acid or the like can be added to make them soluble.

Precipitating agents include ammonia, ammonium carbonate,
Examples thereof include aqueous solutions of caustic soda, caustic potash, sodium carbonate, oxalic acid, ammonium oxalate, and organic reagents such as oxine and amine. Ammonia gas may be used.

To form a precipitate of the constituents, it is desirable to carry out the stirring of the liquid.

Furthermore, after the precipitation of the component A, the component B or the mixed component of A and B is generated, the type and concentration of the precipitation-forming liquid may be changed to a suitable one for the remaining components for precipitation.

Regarding the washing of the precipitate, if alcohols such as ethanol are used, the condensation of the precipitate is controlled in the subsequent drying and calcination steps, and good results are obtained.

In addition to the components A and B, when a trace amount component for controlling the sinterability and characteristics of the ceramic raw material powder is added, it may be allowed to coexist in an aqueous solution to cause precipitation, and the powder is added by a dry method. May be.

When the obtained precipitate is dried and calcined at 400 to 1200 ° C,
A uniform and easily sinterable raw material powder is obtained. Calcination temperature is 40
If the temperature is lower than 0 ° C, the formation reaction and degassing are not completed, and if the temperature exceeds 1200 ° C, the powder particles become coarse and the sinterability deteriorates.

〔The invention's effect〕

According to the present invention, tantalum, niobium and barium, bismuth, lead, strontium, magnesium and the like are not coprecipitated, so high purity tantalum purified by solvent extraction or ion exchange method after dissolution of ore, fluoride aqueous solution of niobium It can be used as it is as a raw material liquid, and therefore, inexpensive industrial production can be put into practical use, and a ceramic raw material powder having a uniform density and excellent sinterability can be obtained by a wet method. Of course, an aqueous fluoride solution may be appropriately concentrated or diluted before use.

Further, since multiple precipitates are generated without coprecipitating all the constituent components of the ceramic raw material powder, these precipitates are in an interdispersed state, and a highly bulky and easily sinterable product is obtained.

Furthermore, since multiple precipitations are generated, the type and concentration of the precipitating agent suitable for each component can be selected, and the ceramic raw material powder of the target component can be easily obtained.

Further, it is possible to easily obtain a high density and uniform ceramic raw material powder without the nonuniformity of the composition components as in the conventional dry method.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 Ba (NO ₃ ) ₂ 39.9 g, Zn (NO ₃ ) ₂ 10.6 g (Zn was found to lose 10% by the following precipitation operation. Therefore, 1.1 times the theoretical amount was used. 5) was prepared and was stirred to prepare an aqueous solution 11 containing 25 g of ammonium bicarbonate.
A coprecipitate of carbonate and hydroxide was prepared by dropping into N1 0.11. While stirring the aqueous solution in which this coprecipitate was suspended, an aqueous solution 11 in which 22.5 g of Ta ₂ O ₅ was dissolved in hydrofluoric acid was added, and 5N containing 5 g of ammonium bicarbonate was further added.
Ammonia water 0.21 was added to obtain uniform precipitates of barium, zinc, tantalum carbonate and hydroxide. Filter, wash,
After drying, it is calcined at 1100 ° C for 2 hours and then Ba (Zn _1/3 Ta _2/3 ) O ₃
BZT raw material powder having the composition of was obtained. When the obtained calcined powder was observed with an electron microscope, it was confirmed that the fine particles were 0.2 μm on average. Diameter of the powder under pressure of 1 t / cm ²
It was molded into a thickness of 30 mm and a thickness of 3 mm, and sintered in air at atmospheric pressure at 1400 ° C for 2 hours.

Comparative Example 1 Commercially available powders of BaCO ₃ , ZnO and Ta ₂ O ₅ were mixed with Ba (Zn _1/3 Ta _2/3 ) O ₃
1100 after mixing in a ball mill and mixing
After calcination for 2 hours at ℃, it was crushed again with a ball mill. When the powder was observed with an electron microscope, it was composed of irregular particles including secondary particles and having an average particle diameter of about 2.0 μm.
The powder was molded under a pressure of 1 t / cm ^{2 to have} a diameter of 30 mm and a thickness of 3 mm, and sintered in air at atmospheric pressure at 1400 ° C. for 2 hours.

Table 1 shows the results of comparing the characteristics of Example 1 and Comparative Example 1 described above. As a result, it is clear that the sintered body using the powder prepared by the method of the present invention is superior to the sintered body obtained by the conventional method in terms of Q value, ε _r and sintering temperature.

Further, as a result of measuring the composition variation of the calcined powders of the above-mentioned Example 1 and Comparative Example 1 by the X-ray diffraction method, it was found that the powder according to the method of the present invention was a uniform powder with little composition variation. .

Example 2 Ba (NO ₃ ) ₂ 39.3 g, Zn (NO ₃ ) ₂ 10.5 g (Zn was found to lose 10% by the following precipitation operation. Therefore, 1.1 times the theoretical amount was used. 1 l of an aqueous solution containing 25 g of ammonium bicarbonate, which was stirred.
A coprecipitate of carbonate and hydroxide was prepared by dropping into 0.1 l of N-ammonia. While stirring the aqueous solution in which this coprecipitate was suspended, 1 l of an aqueous solution of 13.3 g of Nb ₂ O ₅ dissolved in hydrofluoric acid was added, and 5 N containing 5 g of ammonium bicarbonate was further added.
Ammonia water 0.21 was added to obtain uniform precipitates of barium, zinc, niobium carbonate and hydroxide. After filtration, washing with water, drying, and calcination at 1100 ° C. for 2 hours, a BZN raw material powder having a composition of Ba (Zn _1/3 Nb _2/3 ) O ₃ was obtained. When the obtained calcined powder was observed with an electron microscope, it was confirmed that the fine particles were 0.2 μm on average. The powder has a diameter of 30 under a pressure of 1 t / cm ^2.
mm, thickness 3 mm, and sintered in air at atmospheric pressure at 1400 ° C. for 2 hours.

Comparative Example 2 Commercially available powders of BaCO ₃ , ZnO and Nb ₂ O ₅ were mixed with Ba (Zn _1/3 Ta _2/3 ) O ₃
1100 after mixing in a ball mill and mixing
After calcination for 2 hours at ℃, it was crushed again with a ball mill. When the powder was observed with an electron microscope, it was composed of irregular particles including secondary particles and having an average particle diameter of about 2.0 μm.
The powder was molded under a pressure of 1 t / cm ^{2 to have} a diameter of 30 mm and a thickness of 3 mm, and sintered in air at atmospheric pressure at 1400 ° C. for 2 hours.

Table 2 shows the results of comparing the characteristics of Example 2 and Comparative Example 2 described above. As a result, it is clear that the sintered body using the powder prepared by the method of the present invention is superior to the sintered body obtained by the conventional method in terms of Q value, ε _r and sintering temperature.

Further, as a result of measuring the compositional variation of the calcined powders of the above-mentioned Example 2 and Comparative Example 2 by the X-ray diffraction method, it was found that the powder according to the method of the present invention was a uniform powder with little compositional variation. .

Example 3 Ba (NO ₃ ) ₂ 39.9 g, Zn (NO ₃ ) ₂ 10.6 g (Zn was found to lose 10% by the following precipitation operation. Therefore, 1.1 times the theoretical amount was used. 1 l of an aqueous solution containing 25 g of ammonium bicarbonate, which was stirred.
A coprecipitate of carbonate and hydroxide was prepared by dropping into 0.1 l of N-ammonia. With stirring an aqueous solution suspended in the coprecipitate, to which Ta ₂ O ₅ 18.0 g, a Nb ₂ O ₅ 2.7 g was added and dissolved solution 1l hydrofluoric acid, further ammonium bicarbonate 5g
0.2 L of 5N aqueous ammonia containing was added to obtain a uniform precipitate of barium, zinc, tantalum, niobium carbonate and hydroxide. After filtration, washing with water, drying, and calcination at 1100 ° C. for 2 hours, a BZNT raw material powder having a composition of Ba (Zn _0.33 Ta _0.53 Nb _0.14 ) O ₃ was obtained. When the obtained calcined powder was observed with an electron microscope, it was confirmed that the fine particles were 0.2 μm on average. The powder was molded under a pressure of 1 t / cm ^{2 to have} a diameter of 30 mm and a thickness of 3 mm, and sintered in air at atmospheric pressure at 1400 ° C. for 2 hours.

Comparative Example 3 Commercially available powders of BaCO ₃ , ZnO, Nb ₂ O ₅ and Ta ₂ O ₅ were mixed with Ba (Zn _0.33 Ta
_0.53 Nb _0.14 ) O ₃ was compounded, mixed in a ball mill, calcined at 1100 ° C. for 2 hours, and then pulverized again in the ball mill. When the powder was observed with an electron microscope, it was composed of irregular particles having an average particle diameter of about 1.8 μm including secondary particles. The powder was molded under a pressure of 1 t / cm ^{2 to have} a diameter of 30 mm and a thickness of 3 mm, and sintered in air at atmospheric pressure at 1400 ° C. for 2 hours.

Table 3 shows the results of comparing the characteristics of Example 3 and Comparative Example 3 described above. As a result, it is clear that the sintered body using the powder prepared by the method of the present invention has a larger Q value and a relatively larger dielectric constant than the sintered body obtained by the conventional method. And found to be excellent.

Example 4 To an aqueous solution 1 containing 28.1 g of TaF ₅ was added 5N ammonia water 0.2 containing 5 g of ammonium bicarbonate to form a precipitate of a tantalum compound, which was filtered, and the precipitate was washed with water. Fluoride ions were removed from the precipitate. Ba
_{(NO 3) 2 39.9g, Zn} (NO 3) 2 10.6g (Zn are found to loss of 10% by the following precipitation procedure. Thus using 1.1 times the stoichiometric amount.) Containing Aqueous Solution 1 was prepared, and the above-described precipitate from which fluorine ions had been removed was dispersed in this aqueous solution. With this dispersion, ammonium bicarbonate 25
Homogeneous mixture of barium, zinc, tantalum carbonate and hydroxide was obtained by uniformly mixing with 0.1 g of 5N ammonia containing g. After filtration, washing with water, drying, and calcination at 1100 ° C. for 2 hours, a BZT raw material powder having a composition of Ba (Zn _1/3 Ta _2/3 ) O ₃ was obtained.
When the obtained calcined powder was observed with an electron microscope, the average
It was confirmed that the particles were uniform fine particles of 0.2 μm. The powder was molded under a pressure of 1 t / cm ^{2 to} a diameter of 30 mm and a thickness of 3 mm, and was sintered in air at 1400 ° C. for 2 hours under normal pressure.

Comparative Example 4 Commercially available powders of BaCO ₃ , ZnO, and Ta ₂ O ₅ were mixed with Ba (Zn _1/3 Ta _2/3 ) O.
Formulate to be the composition of ₃ and mix with a ball mill, then 110
After calcination at 0 ° C. for 2 hours, it was ground again with a ball mill. When the powder was observed with an electron microscope, it was composed of irregular particles including secondary particles and having an average particle diameter of about 2.0 μm. The powder was molded under a pressure of 1 t / cm ^{2 to} a diameter of 30 mm and a thickness of 3 mm, and was sintered in air at 1400 ° C. for 2 hours under normal pressure.

For the above-mentioned Example 4 and Comparative Example 4, the sintered density of the sintered body,
The results of measuring the dielectric constant and the dielectric loss are shown in Table 4.

As is apparent from the above data, the sintered body using the powder prepared by the manufacturing method of the present invention is superior to the sintered body obtained by the conventional method in terms of Q value, ε _r and sintered density. It is clear that

Further, as a result of measuring the composition variation of the calcined powders of Example 4 and Comparative Example 4 described above by the X-ray diffraction method, it was found that the powder produced by the production method of the present invention was a uniform powder with little composition variation. It was.

Example 5 To an aqueous solution 1 containing 18.8 g of NbF ₅ was added 0.2 N of 5N ammonia containing 5 g of ammonium bicarbonate to form a niobium compound precipitate, which was filtered, and the precipitate was washed with water. Fluoride ions were removed from the precipitate. Ba
Containing (NO ₃ ) ₂ 39.3 g and Zn (NO ₃ ) ₂ 10.5 g (Zn is known to lose 10% due to the following precipitation operation. Therefore, 1.1 times the theoretical amount was used). Aqueous Solution 1 was prepared, and the above-described precipitate from which fluorine ions had been removed was dispersed in this aqueous solution. With this dispersion, ammonium bicarbonate 25
Homogeneous mixture of barium, zinc, niobium carbonate and hydroxide was obtained by uniformly mixing with 0.1 g of 5N ammonia containing g. After filtration, washing with water, and drying, calcine at 1100 ° C for 2 hours,
A BZN raw material powder having a composition of Ba (Zn _1/3 Nb _2/3 ) O ₃ was obtained. When the obtained calcined powder was observed with an electron microscope, the average was 0.2.
It was confirmed that the particles were uniform fine particles of μm. 1t of the powder
It was molded into a diameter of 30 mm and a thickness of 3 mm under a pressure of / cm ² , and sintered in air at 1400 ° C. for 2 hours under normal pressure.

Comparative Example 5 Commercially available powders of BaCO ₃ , ZnO and Nb ₂ O ₅ were mixed with Ba (Zn _1/3 Nb _2/3 ) O.
Formulate to be the composition of ₃ and mix with a ball mill, then 110
After calcination at 0 ° C. for 2 hours, it was ground again with a ball mill. When the powder was observed with an electron microscope, it was composed of irregular particles including secondary particles and having an average particle diameter of about 2.0 μm. The powder was formed under a pressure of 1 t / cm ^{2 to have} a diameter of 30 mm and a thickness of 3 mm, and was sintered in air under atmospheric pressure at 1400 ° C. for 2 hours.

For the above-mentioned Example 5 and Comparative Example 5, the sintered density of the sintered body,
Table 5 shows the results of measuring the dielectric constant and the dielectric loss.

As is apparent from the above data, the sintered body using the powder prepared by the manufacturing method of the present invention is superior to the sintered body obtained by the conventional method in terms of Q value, ε _r and sintered density. It is clear that

In addition, as a result of measuring the composition variation of the calcined powders of Example 5 and Comparative Example 5 described above by the X-ray diffraction method, it was found that the powder produced by the production method of the present invention was a uniform powder with little composition variation. It was. Example 6 To an aqueous solution 1 containing 3.8 g of NbF ₅ and 22.5 g of TaF ₅ was added 0.2 N of 5N ammonia containing 5 g of ammonium bicarbonate to form a precipitate of a tantalum compound and a niobium compound, which was filtered. Further, the precipitate was washed with water to remove fluorine ions from the precipitate. Ba (NO ₃ ) ₂ 39.9g, Zn (N
Aqueous solution 1 containing 10.6 g of O ₃ ) ₂ (10% of Zn was found to be lost by the following precipitation operation. Therefore, 1.1 times the theoretical amount was used) was prepared, and this aqueous solution was used. The precipitate from which the above-mentioned fluorine ions were removed was dispersed. This dispersion was uniformly mixed with 0.1 of 5N ammonia containing 25 g of ammonium bicarbonate to obtain a uniform precipitate of barium, zinc, niobium, tantalum carbonate and hydroxide.
After filtration, washing with water, and drying, calcination is performed at 1100 ° C for 2 hours, and then Ba (Zn
A BZNT raw material powder having a composition of _0.33 Nb _0.14 Ta _0.53 ) O ₃ was obtained. When the obtained calcined powder was observed with an electron microscope, the average was 0.
It was confirmed that the particles were uniform fine particles of 2 μm. 1 of the powder
It was formed into a diameter of 30 mm and a thickness of 3 mm under a pressure of t / cm ² , and was sintered in air at 1400 ° C. for 2 hours under normal pressure.

Comparative Example 6 Commercially available powders of BaCO ₃ , ZnO, Nb ₂ O ₅ and Ta ₂ O ₅ were mixed with Ba (Zn _0.33
Nb _0.14 Ta _0.53 ) O ₃ was added to the composition, mixed in a ball mill, calcined at 1100 ° C. for 2 hours, and then pulverized again in the ball mill. When the powder was observed with an electron microscope, it was composed of irregular particles having an average particle diameter of about 1.8 μm including secondary particles. The powder is 30 mm in diameter under a pressure of 1 t / cm ² ,
It was molded to a thickness of 3 mm and sintered in air at 1400 ° C for 2 hours under normal pressure.

Regarding the above Example 6 and Comparative Example 6, the sintered density of the sintered body,
Table 1 shows the measurement results of the dielectric constant and the dielectric loss.

As is apparent from the above data, the sintered body using the powder prepared by the manufacturing method of the present invention is superior to the sintered body obtained by the conventional method in terms of Q value, ε _r and sintered density. It is clear that

In addition, as a result of measuring the compositional variation of the calcined powders of Example 6 and Comparative Example 6 described above by the X-ray diffraction method, it was found that the powder produced by the production method of the present invention had a small compositional variation and was a dense powder. It was.

[Brief description of drawings]

1 (A) and 1 (B) are explanatory views showing the order of precipitation formation when the method of the present invention is specifically carried out.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01B 3/12 313 M Z (72) Inventor Takayuki Furusawa 1626 Hitomi, Omuta-shi, Fukuoka Hirano Dormitory (72) Inventor Hiromitsu Taki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-61-53113 (JP, A) JP-A-62-143859 (JP, A)

Claims (2)

[Claims] 1. A formula ABO ₃ containing at least one of Ta and Nb as a constituent element (wherein A represents one or more oxygen 12-coordinated metal elements, and B represents an oxygen 6-coordinated metal). One of the elements
Represents a species or two or more species. In producing the ceramic raw material powder shown in (1), an excess precipitation forming liquid is uniformly mixed with an aqueous solution of a fluoride of at least one of Ta and Nb to form a precipitate, and then fluoride ions are removed. Then, the aqueous solution in which the precipitate is dispersed and the aqueous solution containing components A and B other than Ta and Nb are sequentially and uniformly mixed to form a dense precipitate of all components, and then the precipitate is calcined at 400 to 1200 ° C. A method for producing a ceramic raw material powder, comprising: 2. The formula ABO ₃ containing at least one of Ta and Nb as a constituent element (wherein A represents one or more oxygen 12-coordinated metal elements, and B represents an oxygen 6-coordinated metal). One of the elements
Represents a species or two or more species. In producing the ceramic raw material powder shown in), a precipitation forming liquid in which compound powders of components A and B other than Ta and Nb are dispersed is uniformly mixed with an aqueous solution of at least one fluoride of Ta and Nb. To form a dense precipitate of all components, and then the precipitate is 400-1200 ℃
A method for producing a ceramic raw material powder, which comprises calcination at.