HK1082318B - Hard magnetic composition, permanent magnet powder, method for permanent magnet powder, and bonded magnet - Google Patents

Description

Hard magnetic composition, permanent magnet powder, method for producing permanent magnet powder, and bonded magnet

Technical Field

The present invention relates to a hard magnetic composition suitable for use as a permanent magnet material for use in equipment requiring a magnetic field, such as a speaker and a motor. The present invention also relates to a material for permanent magnets, and particularly to a magnet powder suitable for use as a material for bonded magnets and a method for producing the same.

Background

Among rare earth magnets, R-T-B based rare earth permanent magnets are used in various applications in electrical equipment such as speakers and motors because they have excellent magnetic properties, and Nd as a main component is abundant and relatively inexpensive.

However, in recent years, demands for downsizing of electric appliances have been further increased, and development of a new permanent magnet material has been advanced.

Among them, for example, Japanese patent laid-open Nos. 63-273303, 4-241402, 5-65603 and 2000-114017 disclose a crystal having a body-centered cubic lattice or ThMn₁₂A rare earth-iron-based magnet material having a crystal structure of the form type.

Japanese patent laid-open publication No. 63-273303 discloses a compound represented by the formula R_xTi_yA_zFe_aCo_b(wherein R is a rare earth element containing Y, A is 1 or more of B, C, Al, Si, P, Ga, Ge, Sn, S and N, and x is 12 to 30 wt%, Y is 4 to 10 wt%, z is 0.1 to 8 wt%, a is 55 to 85 wt%, and B is 34 wt% or less). Japanese patent application laid-open No. 63-273303 describes that the distance between Fe atoms is changed in a good direction by the element A entering between the atoms.

Japanese unexamined patent publication Hei 4-241402 discloses a compound represented by the formula R_xM_yA_zFe_100-x-y-z(wherein R is at least 1 element selected from rare earth elements containing Y, M is at least 1 element selected from Si, Cr, V, Mo, W, Ti, Zr, Hf and Al, and A is at least 1 element selected from N and C). The permanent magnet has x of 4 to 20%, y of 20% or less, z of 0.001 to 16%, and ThMn in atomic%₁₂The phase of the type crystal structure serves as the main phase. Japanese unexamined patent publication Hei 4-241402 discloses that addition of M element (Si, Ti, etc.) can form ThMn with stability₁₂A rare earth iron-based cubic crystal compound having a crystal structure of the form. Japanese unexamined patent publication Hei 4-241402 also discloses that the A elements (C and N) are effective for increasing the Curie temperature.

Japanese patent application laid-open No. 5-65603 discloses an iron-rare earth based permanent magnet material containing, in atomic percent, R: 3-30%, X: 0.3 to 50%, and the balance consisting essentially of Fe. The magnet material has a phase having a body-centered cubic lattice structure as a main phase. Further, Japanese patent application laid-open No. 5-65603 proposes: by substituting a part of Fe with an M element (a combination of 1, 2 or more elements selected from among Ti, Cr, V, Zr, Nb, Al, Mo, Mn, Hf, Ta, W, Mg, Si, Sn, Ge, Ga), it is made to contain M: 0.5 to 30 percent. In Japanese patent laid-open No. 5-65603, the M element is established as an element having a great effect on the generation of a body-centered cubic lattice structure.

In addition, Japanese patent laid-open No. 2000-114017 discloses a method using a general formula (R)_1-uM_u)(Fe_1-v-wCo_vT_w)_xA_y(wherein R, M, T, A represents R represents at least 1 element selected from rare earth elements containing Y; M represents at least 1 element selected from Ti and Nb; T represents at least 1 element selected from Ni, Cu, Sn, V, Ta, Cr, Mo, W and Mn; A represents at least 1 element selected from Si, Ge, Al and Ga; and u, V, W, x and Y represent 0.1. ltoreq. u.ltoreq.0.7, 0. ltoreq. v.ltoreq.0.8, 0. ltoreq. w.ltoreq.0.1, 5. ltoreq. x.ltoreq.12 and 0.1. ltoreq. y.ltoreq.1.5, respectively). The main hard magnetic phase of the permanent magnet material has ThMn₁₂A crystalline structure. Japanese laid-open patent publication No. 2000-114017 discloses that substitution of R element by M element can reduce the content of ThMn₁₂Phase of type crystal structure (hereinafter sometimes referred to as "ThMn₁₂Phase ") of the element to be stabilized, i.e., Si, Ge, etc.

Rare earth permanent magnets are required to have high magnetic properties and low cost. Among rare earth elements constituting the rare earth permanent magnet, Nd is less expensive than Sm, and therefore, it is preferable that Nd, which is less expensive, be a main component of the rare earth elements than Sm, which is expensive. However, when Nd is used, ThMn₁₂The formation of the phase is difficult, and a high-temperature and long-time heat treatment is required for the production thereof. For example, in the above-mentioned Japanese patent application laid-open No. Hei 5-65603, annealing is carried out at 900 ℃ for 7 days; in addition, in JP-A-4-241402 and JP-A-2000-114017, Sm is used as only the rare earth element with some exceptions.

Disclosure of Invention

Accordingly, an object of the present invention is to: to provide a method for easily producing ThMn even when Nd is used as a rare earth element₁₂Hard magnetic compositions of phases, permanent magnet powders, and the like.

The present inventors obtained the following findings: by adding predetermined amounts of Ti and Si simultaneously, even when Nd is used as a rare earth element, ThMn can be easily produced₁₂A phase of crystalline structure. Also, the following findings were obtained: by further adding N and/or C to a compound obtained by simultaneously adding predetermined amounts of Ti and Si, sufficient magnetic properties can be obtained as a hard magnetic composition for a permanent magnet.

The present invention has been made based on the above findings, and provides a hard magnetic composition characterized in that: the hard magnetic composition has a general formula of R (Fe)_100-y-wCo_wTi_y)_xSi_zA_v(in the general formula, R is at least 1 element selected from rare earth elements (wherein the rare earth elements are concepts containing Y), 50 mol% or more of R is Nd, A is N and/or C), and the molar ratio of the general formula satisfies: x is 10 to 12.5, y is (8.3-1.7 xz) -12.3, z is 0.1 to 2.3, v is 0.1 to 3, w is 0 to 30, and (Fe + Co + Ti + Si)/R > 12.

In addition, the present inventors obtained the following findings: by replacing a part of R with Zr and/or Hf, a hard magnetic composition exhibiting higher saturation magnetization can be obtained. In this case, the composition of the hard magnetic composition can be set as described below: the general formula is R1_1-uR2_u(Fe_100-y-wCo_wTi_y)_xSi_zA_v(in the general formula, R1 is at least 1 element selected from rare earth elements (wherein the rare earth elements are the concept containing Y), 50 mol% or more of R1 is Nd, R2 is Zr and/or Hf, A is N and/or C), and the molar ratio of the general formula satisfies: u is 0.18 or less, y is 4.5 to 12.3, x is 11 to 12.8, z is 0.1 to 2.3, v is 0.1 to 3, w is 0 to 30, and (Fe + Co + Ti + Si)/(R1+ R2) > 12.

In order to obtain the effect of improving saturation magnetization, the amount (u) of the R2 element (Zr and/or Hf) is preferably set to 0.04 to 0.06.

In the case where a part of R is replaced with Zr and/or Hf, the hard magnetic composition may be set to be substantially composed of a single-phase structure of a hard magnetic phase, and the hard magnetic phase may be set to ThMn₁₂A crystalline structure. In the present specification, the substitution of a part of R with Zr and/or Hf is sometimes referred to as "substitution of Zr (Hf)".

The hard magnetic composition of the present invention can obtain a single-phase structure of a hard magnetic phase even when 70 mol% or more of R is Nd regardless of the presence or absence of Zr (Hf) substitution, and the single-phase structure can be set to have ThMn₁₂A phase of crystalline structure.

In the hard composition of the present invention, a is preferably N.

In addition, whether or not there is a zr (hf) substitution, it is preferable that: x is 11 to 12.5, z is 0.2 to 2.0, v is 0.5 to 2.5, and w is 10 to 25.

According to the present invention described above, a hard magnetic composition comprising an R-Ti-Fe-Si-A compound or an R-Ti-Fe-Co-Si-A compound (in the general formula, R is at least 1 element selected from rare earth elements (wherein the rare earth element is a concept containing Y), 80 mol% or more of R is Nd, A is N and/or C), and a hard magnetic phase single-phase structure having a saturation magnetization (σ s) of 120emu/g or more and having an anisotropy of 120emu/g or more can be obtainedMagnetic field of opposite polarity (H)_A) Is 30kOe or more. This hard magnetic composition has an advantage in cost in obtaining a permanent magnet because Nd accounts for 80 mol% or more of R.

Here, the single-phase structure can be set to have ThMn₁₂A phase of crystalline structure.

The hard magnetic composition of the present invention can also exhibit excellent magnetic properties, such as an anisotropic magnetic field (H)_A) 40kOe or more and a saturation magnetization (. sigma.s) of 130emu/g or more.

In addition, from the viewpoint of reducing the manufacturing cost of the permanent magnet, it is desirable that the Nd is not required to be subjected to heat treatment at a high temperature for a long time. The present inventors have studied an intermetallic compound composed of R (R is at least 1 element selected from rare earth elements (wherein the rare earth element is a concept containing Y)) and T (a transition metal element containing Fe and Ti as essential components) and having a composition in which the molar ratio of R to T is about 1: 12. The result is: when Si exists as a gap-type element (also referred to as an intrusion-type element), high saturation magnetization and an anisotropic magnetic field can be obtained without applying a heat treatment at a high temperature for a long time. Further, it was found that when N is present as a gap-type element, both saturation magnetization and anisotropic magnetic field were further improved.

In addition, the present inventors have confirmed during the above studies that: si and N are common in the gap type elements, but their influence on the crystal lattice by invasion differs. As will be described in detail later, Si has an effect of shrinking the lattice, particularly the a-axis of the crystal lattice. In contrast, N has the effect of causing isotropic expansion of the crystal lattice. The result is: and ThMn based on the American Society for Testing and Materials (ASTM)₁₂The novel intermetallic compound according to the present inventors has a larger value of c/a than the axial ratio of the c-axis to the a-axis (hereinafter referred to as c/a) of the crystal lattice of the type compound. Furthermore, based onThMn of ASTM₁₂The compound of type (III) has a c/a of 0.558.

The present invention based on the above findings provides a hard magnetic composition characterized in that: the hard magnetic composition is composed of a single-phase structure of an intermetallic compound in which the molar ratio of R to T (R is 1, 2 or more rare earth elements including Y, and T is a transition metal element containing Fe and Ti as essential components) is about 1: 12, and Si and A (A is 1 or 2 of N and C) exist as interstitial elements between crystal lattices of the intermetallic compound.

In the hard magnetic composition of the present invention, the molar ratio of R to T is preferably 1: 10 to 1: 12.5.

ThMn as described in the present invention₁₂A crystalline structure of the form, which can be identified as ThMn in X-ray diffraction₁₂Form crystal structure. However, it is compatible with the ThMn specified by ASTM₁₂The compounds of type (I) differ in the c/a value. That is, in the hard magnetic composition of the present invention, if the ratio of the lattice constant of the c-axis and the lattice constant of the a-axis of the crystal lattice of the intermetallic compound is c1/a1, ThMn based on American Society for Testing and Materials (ASTM)₁₂When the ratio of the lattice constant of the c-axis to the lattice constant of the a-axis of the crystal lattice of the type compound is c2/a2(c2/a2 is 0.558), c1/a 1> c2/a 2. In this case, Si causes anisotropic contraction of the crystal lattice and A causes isotropic expansion of the crystal lattice, whereby c1/a 1> c2/a2 can be obtained.

However, SmCo magnet powder and NdFeB magnet powder are known as permanent magnet powder that has been used for bonded magnets and the like. From the viewpoint of cost reduction, Nd, which is inexpensive, is preferably a main component of rare earth elements, compared to Sm, which is expensive. Thus, having Nd₂Fe₁₄B₁Magnet powders of phase are widely used, but cheaper magnet powders are still desired.

The present inventors have made various studies to obtain such a magnet powder. As a result, obtainThe following insights: by making the crystal structure of the hard magnetic composition of the present invention fine, a sufficient coercive force can be exhibited as a permanent magnet powder. That is, the permanent magnet powder of the present invention is characterized in that: the magnet powder is represented by the general formula R (Fe)_100-y-wCo_wTi_y)_xSi_zA_v(in the general formula, R is at least 1 element selected from rare earth elements (wherein the rare earth elements are concept containing Y), and 50 mol% or more of R is Nd, A is N and/or C); and has a composition in which the molar ratio of the above general formula satisfies: x is 10 to 12.8, y is (8.3-1.7 xz) to 12.3, z is 0.1 to 2.3, v is 0.1 to 3, w is 0 to 30, and (Fe + Co + Ti + Si)/R > 12; and is composed of an aggregate of particles having an average crystal grain diameter of 200nm or less.

In the permanent magnet powder of the present invention, each particle constituting the powder preferably has ThMn₁₂The phase having a crystal structure of the type form is a main phase, and particularly preferably substantially composed of a material having ThMn₁₂A phase of a crystalline structure of the form type.

In the permanent magnet powder of the present invention, the powder having substantially ThMn can be obtained even when Nd is 70 mol% or more of R₁₂The phase of the crystal structure has a single-phase structure, and thus, the cost can be reduced.

As described above, the magnet powder of the present invention is characterized by having a fine crystal structure. Such a fine crystal structure can be realized by subjecting amorphous or microcrystalline powder obtained by the rapid solidification treatment to a predetermined heat treatment. In the method for producing a permanent magnet powder of the present invention, first, a powder is produced, wherein the powder is represented by the general formula R (Fe)_100-y-wCo_wTi_y)_xSi_z(in the general formula, R is at least 1 element selected from rare earth elements (wherein the rare earth elements are the concept of containing Y), and 50 mol% or more of R is Nd); and has a composition in which the molar ratio of the above general formula satisfies: x is 10 to 12.8, y is (8.3 to 1.7 xz) to 12.3,z is 0.1-2.3, w is 0-30, and (Fe + Co + Ti + Si)/R > 12; and subjected to a rapid solidification treatment. Then, the powder is subjected to heat treatment in an inert atmosphere at a temperature ranging from 600 to 850 ℃ for 0.5 to 120 hours. Then, the heat-treated powder is subjected to nitriding treatment or carbonizing treatment.

In the method for producing a permanent magnet powder according to the present invention, the powder subjected to the rapid solidification treatment has any one structure of an amorphous phase, a mixed phase of an amorphous phase and a crystalline phase, or a crystalline phase. Among these, from the viewpoint of ease of control of the crystal grain size after the subsequent heat treatment, it is preferable to set a mixed phase of an amorphous phase and a crystalline phase, and it is particularly preferable to set a mixed phase of a rich crystalline phase.

In the method for producing permanent magnet powder of the present invention, although the specific method of the rapid solidification treatment is not limited, the single-roll method is preferably applied for reasons such as productivity and stable obtainment of a desired structure after cooling solidification. The peripheral speed of the roll is preferably set to 10 to 100m/s when the single roll method is applied. The composition of the alloy to be obtained may vary depending on the diameter of the nozzle for discharging the molten metal and other conditions such as the material of the roller, but the powder subjected to the rapid solidification treatment in this range may have any structure of an amorphous phase, a mixed phase of an amorphous phase and a crystalline phase, or a crystalline phase.

In the method for producing a permanent magnet powder of the present invention, the powder subjected to the rapid solidification treatment is subjected to a heat treatment for crystallizing an amorphous phase or for adjusting the grain size of crystal grains constituting a crystal phase.

By using the permanent magnet powder obtained by the present invention, a bonded magnet can be produced. The bonded magnet comprises a permanent magnet powder and a resin phase for bonding the permanent magnet powder. The crystalline hard magnetic particles constituting the permanent magnet powder are characterized in that: the hard magnetic particles are represented by the general formula R (Fe)_100-y-wCo_wTi_y)_xSi_zA_v(in the general formula, R is at least 1 element selected from rare earth elements(wherein the rare earth element is a concept containing Y), and 50 mol% or more of R is Nd, and A is N and/or C), and the molar ratio of the above general formula satisfies: x is 10 to 12.8, y is (8.3-1.7 xz) -12.3, z is 0.1 to 2.3, v is 0.1 to 3, w is 0 to 30, and (Fe + Co + Ti + Si)/R > 12.

In view of magnetic properties, the hard magnetic particles of the bonded magnet of the present invention preferably have an average crystal grain diameter of 200nm or less.

Drawings

FIG. 1 shows a crystal having Nd (Ti)_8.2Fe_91.8)_11.9Si_zAnd Nd (Ti)_8.2Fe_91.8)_11.9Si_zN_1.5A graph of the relationship between the lattice constant (a-axis, c-axis, and c-axis/a-axis) and the Si amount (z) of the hard magnetic composition of (a).

Fig. 2 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 1 (experimental example 1).

FIG. 3(a) is a graph showing the relationship between the Si amount and the saturation magnetization (. sigma.s); FIG. 3(b) shows the amount of Si and the anisotropic magnetic field (H)_A) A curve of the relationship between.

FIG. 4 is a graph showing the results of X-ray diffraction of samples No.4 and 7 and sample No. 45.

FIG. 5 shows the thermomagnetic curves of sample Nos. 4, 7, 33 and 45.

Fig. 6 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 1 (experimental example 2).

FIG. 7(a) is a graph showing the relationship between the amount of (Fe + Ti) and the saturation magnetization (σ s); FIG. 7(b) shows the amount of (Fe + Ti) and the anisotropic magnetic field (H)_A) A curve of the relationship between.

FIG. 8(a) shows the relationship between the amount of (Fe + Ti) and the saturation magnetization (. sigma.s)A curve of the system; FIG. 8(b) shows the amount of (Fe + Ti) and the anisotropic magnetic field (H)_A) A curve of the relationship between.

Fig. 9 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 1 (experimental example 3).

FIG. 10(a) is a graph showing the relationship between the Ti amount and the saturation magnetization (. sigma.s); FIG. 10(b) shows the amount of Ti and the anisotropic magnetic field (H)_A) A curve of the relationship between.

FIG. 11(a) is a graph showing the relationship between the Ti amount and the saturation magnetization (. sigma.s); FIG. 11(b) shows the amount of Ti and the anisotropic magnetic field (H)_A) A curve of the relationship between.

FIG. 12(a) is a graph showing the relationship between the Ti amount and the saturation magnetization (. sigma.s); FIG. 12(b) shows the amount of Ti and the anisotropic magnetic field (H)_A) A curve of the relationship between.

Fig. 13 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 1 (experimental example 4).

Fig. 14(a) is a graph showing the relationship between the N amount and the saturation magnetization (σ s); FIG. 14(b) shows the N content and the anisotropic magnetic field (H)_A) A curve of the relationship between.

Fig. 15 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 1 (experimental example 5).

Fig. 16 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 1 (experimental example 6).

Fig. 17 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 2 (experimental example 7).

FIG. 18 is a graph showing the results of X-ray diffraction of sample Nos. 63, 91 and 105.

FIG. 19 is an enlarged view of the vicinity of the diffraction angle at which the α -Fe peak is generated.

Fig. 20 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 2 (experimental example 8).

Fig. 21 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 2 (experimental example 9).

Fig. 22 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 2 (experimental example 10).

Fig. 23 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 2 (experimental example 11).

Fig. 24 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 2 (experimental example 12).

Fig. 25 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 2 (experimental example 13).

Fig. 26 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 2 (experimental example 14).

Fig. 27 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 3 (experimental example 15).

FIG. 28 is a thermomagnetic curve of a sample obtained in example 3.

Fig. 29 is a graph showing the composition, magnetic properties, and phase structure of the sample obtained in example 3 (experimental example 16).

FIG. 30 is a graph showing the results of X-ray diffraction with respect to a rapidly solidified sheet.

Fig. 31 is a graph showing the results of X-ray diffraction performed on a heat-treated sample.

FIG. 32 is a photograph showing the results of observation of a structure, which is a heat-treated structure of a sheet obtained at a peripheral speed (Vs) of a roller of 25m/s, by a Transmission Electron Microscope (TEM).

FIG. 33 is a photograph showing the results of observation of a structure, which was heat-treated with a sheet obtained at a peripheral speed (Vs) of a roller of 75m/s, by a Transmission Electron Microscope (TEM).

Fig. 34 is a graph showing the results of measuring the magnetic properties after the nitriding treatment in example 4 (experimental example 17).

Fig. 35 is a graph showing the results of measuring the magnetic properties after the nitriding treatment in example 4 (experimental example 18).

Detailed Description

The following describes embodiments including the best mode of the present invention with respect to a hard magnetic composition, a permanent magnet powder, a method for producing a permanent magnet powder, and a bonded magnet.

First, the reasons for limiting the elements of the present invention will be described.

[ R (rare earth element) ]

R is an element necessary for obtaining high magnetic anisotropy. To form ThMn as a hard magnetic phase₁₂Although Sm is advantageously used, the amount of Nd in R is 50 mol% or more in the present invention in order to achieve a cost advantage. In the present invention, the Nd accounts for 50 mol% or more of R, but ThMn may be caused to exist₁₂Is easy to generate.

However, the present invention allows the rare earth element to be contained in addition to Nd. In this case, it is more preferable to contain at least 1 element selected from Y, La, Ce, Pr, and Sm in addition to Nd. Among them, Pr is particularly preferable because Pr exhibits properties substantially equal to those of Nd, and therefore can obtain a value equivalent to that of Nd in terms of magnetic properties.

According to the present invention, when the ratio of Nd to R is as high as 70 mol% or more, or 90 mol% or more, ThMn, which is a hard magnetic phase, can be obtained₁₂The phase is the main phase structure, and further the structure is composed of ThMn₁₂Monophasic organization of phase composition. As shown in examples described later, according to the present invention, ThMn, which is a hard magnetic phase, can be obtained even when all R are Nd, i.e., Nd is 100 mol% of R₁₂Monophasic organization of phase composition.

[Si]

When Si is added to R (Nd) and Fe together with Ti, it contributes to ThMn as a hard magnetic phase₁₂Stabilization of the phases. In this case, Si has an invaded ThMn₁₂The lattice shrinkage effect is caused by the lattice shrinkage of the phases. When the Si content is less than 0.1 (molar ratio, the same applies hereinafter), Mn is contained₂Th₁₇Phase of type crystal structure (hereinafter referred to as Mn)₂Th₁₇Phase), and when it exceeds 2.3, α -Fe tends to precipitate. Therefore, the present invention recommends setting z as the amount of Si in the range of 0.1 to 2.3. The preferable amount of Si (z) is 0.2 to 2.0, and the more preferable amount of Si (z) is 0.2 to 1.0.

Further, regarding Si, in relation to Fe, Co, Ti and R, the content thereof preferably satisfies: (the molar ratio of Fe + the molar ratio of Co + the molar ratio of Ti + the molar ratio of Si/(the molar ratio of R) > 12, which will be described later.

[Ti]

Ti contributes to ThMn₁₂And (5) generating a phase. Specifically, ThMn is caused by replacing Fe by a predetermined amount of Ti₁₂The generation of the phase becomes easy. In order to sufficiently obtain this effect, it is necessary to set a lower limit of the Ti amount (y) in relation to the Si amount. That is, as shown in examples described later, when the Ti content (y) is less than (8.3 to 1.7 xz (Si content)), α -Fe and Mn are precipitated₂Th₁₇And (4) phase(s). When the Ti amount (y) exceeds 12.3, the saturation magnetization decreases significantly. Therefore, in the present invention, the amount of Ti (y) is set to (8.3-1.7 xz (Si amount)) -12.3, preferably (8.3-1.7 xz (Si amount)) -12, more preferably (8.3-1.7 xz (Si amount)) -10, and still more preferably (8.3-1.7 xz (Si amount)) -9.

In addition, when the sum (x) of the amount of Fe and the amount of Ti is less than 10, both the saturation magnetization and the anisotropic magnetic field are low; when the amount exceeds 12.5, alpha-Fe precipitates. Therefore, the sum (x) of the Fe amount and the Ti amount is set to 10 to 12.5. The sum (x) of the amount of Fe and the amount of Ti is preferably 11 to 12.5.

[ A (N (nitrogen) and/or C (carbon)) ]

A is by invasion of ThMn₁₂Intergranular ThMn of phases₁₂An element which expands the crystal lattice of the phase and is effective for improving the magnetic properties. However, when the A amount (v) exceeds 3.0, the precipitation of α -Fe is observed; further, when the amount (v) of A is less than 0.1, the effect of improving the magnetic properties cannot be sufficiently obtained. Therefore, the amount (v) of A is set to 0.1 to 3.0.

The amount (v) of A is preferably 0.3 to 2.5, and more preferably 1.0 to 2.5.

[Fe，Fe-Co]

The hard magnetic composition of the present invention is substantially Fe, but it is effective to replace a part of Fe with Co, in addition to the above elements. As will be described in examples to be described later, the addition of Co causes the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) to be saturated_A) And is increased. The amount of Co is preferably 30 or less by mole, and more preferably 5 to 20. Furthermore, the addition of Co is not essential.

[ (Fe molar ratio + Co molar ratio + Ti molar ratio + Si molar ratio)/(R molar ratio) > 12]

Fe. The respective contents of Co, Ti and Si are as described above, but the hard magnetic composition of the present invention is set to ThMn₁₂In terms of the monophasic structure of the phase, it is important to satisfy the condition of (Fe + Co + Ti + Si)/R > 12. As will be shown in examples described later, when the above conditions are not satisfied, the saturation magnetization is reduced.

[Zr，Hf]

The composition of the hard magnetic composition of the present invention is explained above.

The hard magnetic composition of the present invention may further contain Zr and/or Hf. Zr and/or Hf are effective for improvement of magnetic characteristics, particularly saturation magnetization.

Zr and/or Hf substitutes for a part of R in the above general formula. Here, since the saturation magnetization ratio u is lower when the substitution amount u representing Zr and/or Hf exceeds 0.18, when part of R is substituted with Zr and/or Hf, u is set to 0.18 or less (not including 0). Preferably, u is 0.01 to 0.15, and more preferably, u is 0.04 to 0.06.

Here, the Ti content (y) in the case of Zr (Hf) substitution is shown.

When Zr (Hf) substitution is performed, the Ti content (y) is set to 4.5 to 12.3. In this case, the amount (y) of Ti is preferably 5 to 12, more preferably 6 to 10, and still more preferably 7 to 9. The sum (x) of the Fe amount, the Co amount and the Ti amount is 11 to 12.8, preferably 11.5 to 12.5.

The method for producing the hard magnetic composition of the present invention can be obtained by a known production method.

As the interstitial element N, a raw material originally containing N can be used. However, it is preferable to infiltrate N by performing treatment (nitriding) in a gas or liquid containing N after the production of a composition containing an element other than N. As the gas into which N can be introduced, N can be used₂Gas, N₂+H₂Mixed gas of (2), NH₃Gases and mixtures thereof. The temperature of the nitriding treatment may be set to 200 to 1000 ℃, preferably 350 to 700 ℃. The nitriding time may be appropriately selected within a range of 0.2 to 200 hours.

The treatment for penetrating C (carbonization treatment) is also the same as the case of N. That is, a raw material originally containing C may be used, or a composition containing an element other than C may be produced and then subjected to a heat treatment in a gas or liquid containing C. Or by heating with a C-containing solidTreatment caused C invasion. Examples of the gas capable of permeating C include CH₄And C₂H₆And the like. Carbon black can be used as the solid containing C. In the carbonization using these, appropriate conditions can be set within the same range of temperature and treatment time as in the nitriding treatment.

< Crystal Structure >

Next, the crystal structure of the hard magnetic composition of the present invention will be described.

The hard magnetic composition of the present invention comprises R (R is at least 1 element selected from rare earth elements (wherein the rare earth elements are a concept containing Y)) and T (a transition metal element containing Fe and Ti as essential components), and is composed of an intermetallic compound in which the molar ratio of R to T is about 1: 12. Si exists between crystal lattices of the intermetallic compound as a gap-type element. In addition, N is also present as a gap-type element in the lattice.

As described above, both Si and N exist between crystal lattices to improve magnetic characteristics. However, Si contracts the lattice and N expands the lattice. Thus, Si and N differ in action. This point will be explained below.

FIG. 1 shows a crystal having Nd (Ti)_8.2Fe_91.8)_11.9Si_zAnd Nd (Ti)_8.2Fe_91.8)_11.9Si_zN_1.5A graph of the relationship between the lattice constant (c-axis, a-axis, and c-axis/a-axis) and the Si amount (z) of the hard magnetic composition of (a). The hard magnetic composition shown in fig. 1 is disclosed in the examples described later.

In fig. 1, no large change in lattice constant of the c-axis is observed even if Si is added. But it is known that: for the a-axis, the lattice constant is significantly reduced by the addition of Si. That is, Si exists between crystal lattices and has a characteristic of causing the crystal lattices to contract anisotropically.

Secondly, it is known that: in fig. 1, by adding N, the lattice constants of the c-axis and the a-axis are both increased. That is, N exists between the lattices and expands the lattice isotropically. As described above, the saturation magnetization, curie temperature, and anisotropic magnetic field can be increased by contracting or expanding the crystal lattice. It is also known from fig. 1: the effect of Si on anisotropically shrinking the lattice does not change even when N is added. Further, Si itself contracts the lattice, but the presence of N makes the effect of improving anisotropy remarkable and makes it easy to form a single-phase structure.

In FIG. 1, the curve marked with the "ASTM" symbol indicates the ThMn according to ASTM₁₂The c-axis lattice constant, the a-axis lattice constant, and the c-axis/a-axis lattice constant of the type compound. Nd (Ti) is known_8.2Fe_91.8)_11.9Si_zWhen z is 0, the lattice constant of the composition is equal to ThMn as described in ASTM₁₂The lattice constants of the type compounds are consistent.

The presence of Si between the crystal lattices can be confirmed by the following fact. For the above Nd (Ti)_8.2Fe_91.8)_11.9Si_zIn the composition containing no Si and the composition containing Si, in which z is 0, both of them were confirmed by X-ray diffraction, and as a result, no change was observed in the basic form of the obtained diffraction peak. Further, it was not confirmed that a peak of Si or a compound of Si and a constituent element of the composition and a peak of α -Fe were present. Further, the lattice constant of the a-axis continuously decreases with an increase in the amount of Si. From this, it can be considered that Si exists between crystal lattices.

In the present invention, N atoms exist between crystal lattices, and both the c-axis and the a-axis are expanded at approximately the same ratio. However, Si exists between crystal lattices, and since only the a-axis is contracted, it can be estimated that Si exists at a specific site in the crystal lattice. Although the position of its presence cannot be determined, because ThMn is shown₁₂The X-ray diffraction pattern of the form compound is considered to occupy a specific position between crystal lattices.

The hard magnetic composition of the present invention exhibits ThMn according to ASTM₁₂Type compounds differ in lattice constant, but X-ray diffraction shows that ThMn can be recognized₁₂Diffraction pattern of type (la) compound. Thus, the hard magnetic composition of the present invention is ThMn₁₂A compound of the formula (I). In the hard magnetic composition of the present invention, the hard magnetic phase is preferably ThMn₁₂A crystalline structure. From the viewpoint of magnetic properties, the hard magnetic phase is substantially composed of ThMn₁₂The structure of the single phase of the form crystal structure is particularly preferable.

The hard magnetic composition of the present invention has been described above. The hard magnetic composition is suitable as a magnet material, and the present inventors have recognized that: by making the crystal structure of the hard magnetic composition finer, a sufficient coercive force can be exhibited as a permanent magnet powder. The permanent magnet powder and the method for producing the same according to the present invention will be described in detail below.

[ Structure of permanent magnet powder ]

First, the structure of the permanent magnet powder of the present invention will be described.

The permanent magnet powder of the present invention is a fine powder having an average crystal grain diameter of 200nm or less, preferably 100nm or less, and more preferably 80nm or less. The present invention can exhibit a coercive force necessary for the permanent magnet powder because of having such a fine structure. In the present invention, means for obtaining such a fine structure will be described later. The grain diameter is a value obtained by observing a quenched alloy subjected to heat treatment by TEM, identifying each crystal grain, obtaining the area of each crystal grain by image processing, and calculating the diameter of a circle by regarding the crystal grain as a circle having the same area as the area. The average crystal grain size is set to an average of crystal grain sizes of all the measurement particles obtained by measuring about 100 crystal grains for each sample.

Has the advantages ofThe permanent magnet powder of the present invention having a fine crystal structure is set to ThMn₁₂The phase is preferably ThMn as the main phase₁₂Monophasic organization of the phases. Further, as to whether it is ThMn or not₁₂The monophasic structure of the phase can be determined according to the criteria described in the examples below.

[ method for producing permanent magnet powder ]

The method for producing the permanent magnet powder of the present invention will be described below.

The permanent magnet powder of the present invention is characterized by having a fine crystal structure as described above, and the fine crystal structure can be obtained by several methods. For example, a method using a molten metal quenching method, a method using mechanical milling or mechanical alloying, a method using a Hydrogenation-disproportionation-dehydrogenation-Recombination (HDDR) method, and the like. Next, a production method using the molten metal quenching method will be described.

The manufacturing method using the molten metal quenching method has 3 main steps of a molten metal quenching step, a heat treatment step, and a nitriding treatment step. The respective steps will be described in order.

< molten Metal quenching step >

The molten metal quenching step is a step of melting the raw material metal prepared to have the above composition to obtain a molten metal, and then quenching and solidifying the molten metal. Specific examples of the solidification method include a single-roll method, a twin-roll method, a centrifugal quenching method, and a gas spray method. Among them, the single roll method is preferably used. The single-roll method is a method in which molten alloy is ejected from a nozzle and made to collide against the circumferential surface of a cooling roll, thereby rapidly cooling the molten alloy, and obtaining a rapidly cooled alloy in the form of a thin strip or a thin sheet. The single-roll method has a high mass productivity and a good reproducibility under a quenching condition, as compared with other molten metal quenching methods.

The rapidly solidified alloy has any one of an amorphous single phase, a mixed phase of an amorphous phase and a crystalline phase, and a single phase of a crystalline phase, depending on the composition and the circumferential speed of the cooling roll. The amorphous phase may be microcrystallized by a subsequent heat treatment. As one measure, when the peripheral speed of the cooling roll is increased, the ratio of amorphous occupancy is increased.

When the circumferential speed of the cooling roll is increased, the obtained quenched alloy becomes thinner, and thus a more homogeneous quenched alloy can be obtained. For the present invention, it is most preferable to have the finally desired microcrystalline structure in a state of being kept unchanged after cooling solidification, but it is not easy to achieve this. On the other hand, it is naturally possible to carry out microcrystallization by heat treatment after obtaining a single-phase structure of an amorphous phase, but there is a risk that the crystal grains grow abnormally based on the previously formed crystal nuclei to form coarse crystal grains. Thus, for the purposes of the present invention, the preferred morphology is to obtain a coagulated structure rich in the microcrystalline phase with the remainder being the amorphous phase.

Therefore, the peripheral speed of the cooling roll is usually set to be in the range of 10 to 100m/s, preferably in the range of 15 to 75m/s, and more preferably in the range of 25 to 75 m/s. When the peripheral speed of the cooling roll is less than 10m/s, the crystal grains are coarsened and it is difficult to obtain a desired fine structure; when the peripheral speed of the cooling roll exceeds 100m/s, the adhesion between the molten alloy and the peripheral surface of the cooling roll is deteriorated, heat transfer cannot be efficiently performed, and the facility cost is increased. In the molten metal quenching step, Ar gas and N gas are preferably used₂Gas, or the like in a non-oxidizing atmosphere.

< Heat treatment step >

The quenched alloy obtained in the molten metal quenching step is then subjected to heat treatment. The effect of this heat treatment is: under the condition that the quenching alloy is an amorphous phase single phase, microcrystals with the grain size meeting the requirements of the invention are generated; in addition, when the rapidly cooled alloy is a mixed phase of an amorphous phase and a crystalline phase, the amorphous phase is microcrystallized and the crystal grain size is controlled to be the particle size required in the present invention; when the rapidly cooled alloy has a single-phase structure having a crystal phase, the crystal grain size is controlled to be the particle size required in the present invention. Therefore, if the microstructure required for the permanent magnet powder of the present invention cannot be obtained in a state where the alloy is quenched, heat treatment is necessary.

The treatment temperature of the heat treatment is 600-850 ℃, preferably 650-800 ℃, and more preferably 670-750 ℃. The treatment time varies depending on the treatment temperature, but is usually set to about 0.5 to 120 hours. The heat treatment is preferably performed in a non-oxidizing atmosphere such as Ar, He, or vacuum.

< nitriding step >

After the heat treatment, the quenched alloy is subjected to nitriding treatment. As N as the interstitial element, a raw material originally containing N can be used, but it is preferable that N is penetrated by treatment (nitriding) in a gas or liquid containing N after the production of a composition containing an element other than N. As the gas into which N can be introduced, N can be used₂Gas, N₂+H₂Mixed gas of (2), NH₃Gases and mixtures thereof. Further, it is preferable to perform the treatment by using these gases as high-pressure gases in order to increase the nitriding treatment speed.

The temperature of the nitriding treatment is set to 200 to 450 ℃, preferably 350 to 420 ℃, and the nitriding treatment time can be appropriately selected within the range of 0.2 to 200 hours. In the same manner as the treatment (carbonization treatment) for penetrating C, a raw material originally containing C may be used, or after a composition containing an element other than C is produced, a heat treatment may be performed in a gas or liquid containing C. Alternatively, C may be infiltrated by heat treatment together with a solid containing C. The gas capable of permeating C includes CH₄And C₂H₆And the like. Carbon black may be used as the solid containing C. In the carbonization using these, appropriate conditions can be set within the same temperature and treatment time range as in the nitriding.

The above is the basic process for obtaining the permanent magnet powder of the present invention, and melting is employedThe alloy obtained by the metal quenching method may be pulverized at any stage of before the heat treatment step, before the nitriding step, or after the nitriding step. This is because the alloy obtained by the molten metal quenching method is generally different in size from the size required for the permanent magnet powder for a bonded magnet. Pulverizing in Ar and N₂Etc. under inert gas.

The average particle size of the permanent magnet powder is not particularly limited, but a preferred particle size is one in which a region having an excessively large difference in crystallinity is not present as much as possible in the same particle, and a preferred particle size is one that can be used as a permanent magnet powder. Specifically, when the bonded magnet is applied, the average particle size is preferably set to 10 μm or more in general, but in order to obtain sufficient oxidation resistance, the average particle size is preferably set to 30 μm or more, more preferably 50 μm or more, and still more preferably 70 μm or more. By setting the average particle diameter to such a level, a bonded magnet having a high density can be obtained. On the other hand, the upper limit of the average particle diameter is preferably 500. mu.m, and more preferably 250. mu.m. The average particle diameter referred to herein may be specifically defined by the intermediate diameter D50. D50 is the particle size when the cumulative mass is 50% of the cumulative mass of all particles, i.e., the cumulative frequency of the particle size distribution curve.

The permanent magnet powder obtained above can be supplied to a bonded magnet. The bonded magnet can be produced by bonding particles constituting permanent magnet powder with an adhesive. Bonded magnets are classified into several categories according to their manufacturing methods. For example, there are compression bonded magnets using press molding and injection bonded magnets using injection molding. Various resins are preferably used as the binder, but a metal binder may be used to produce a metal-bonded magnet. The type of the resin binder is not particularly limited, and may be appropriately selected from various thermosetting resins such as epoxy resin and nylon, and various thermoplastic resins depending on the purpose. The kind of the metal binder is not particularly limited. The content ratio of the binder to the permanent magnet powder and the conditions such as the pressure at the time of molding are not particularly limited, and may be appropriately selected from the range in general. However, in order to prevent coarsening of crystal grains, it is preferable to avoid using a method requiring high-temperature heat treatment.

The above description has been made of an example in which a fine crystal structure is obtained by a molten metal quenching method, but the present invention is not limited to this method. As another method, there is a method using mechanical polishing. The method comprises 3 main steps of mechanical polishing, heat treatment and nitriding. The heat treatment step and the nitriding step are the same as those employed in the molten metal quenching method described above, and therefore, the description thereof is omitted here.

Mechanical polishing is performed by continuously applying mechanical impact to alloy particles having a predetermined particle diameter to convert the particles having a crystalline structure into an amorphous phase. The application of the mechanical impact can be performed by using a ball mill, a vibration mill (shaker mill), and a vibration mill which are well known as a pulverizer. By treating the alloy particles with these pulverizers, the structure of the particles can be made amorphous.

The alloy particles can be produced by a conventional method. For example, an ingot having a predetermined composition is prepared and then the ingot is pulverized. Alternatively, a ribbon or a flake obtained by a molten metal quenching method may be subjected to mechanical polishing. In this case, it is needless to say that a thin strip or sheet which is originally in an amorphous state is not necessarily used.

The permanent magnet powder of the present invention can be obtained by performing the heat treatment step and the nitriding step in this order on the alloy powder amorphized by mechanical polishing. The bonded magnet of the present invention can be obtained by using the permanent magnet powder.

As a method for obtaining a fine crystal structure, there is a heat treatment (HDDR) for removing hydrogen after keeping at a high temperature in a hydrogen atmosphere. The present invention can also obtain a fine crystal structure by using the HDDR. The powder subjected to HDDR is subjected to a heat treatment step and a nitriding treatment step in this order, whereby the permanent magnet powder of the present invention can be obtained. The bonded magnet of the present invention can be obtained by using the permanent magnet powder.

(examples)

Next, the present invention will be described in further detail with reference to specific examples.

[ 1 st embodiment ]

The experimental results (experimental examples 1 to 6) which are the reasons for the limitation of the above composition range are shown as example 1. As described above, the hard magnetic composition of the present invention exhibits ThMn as described in ASTM₁₂Type compounds differ in lattice constant but appear to be identifiable as ThMn in X-ray diffraction₁₂Diffraction pattern of type (la) compound.

< Experimental example 1>

First, the experimental result (experimental example 1) of the dependency of the phase state and the magnetic characteristic on the z value (Si amount) will be described.

The alloy composition is Nd- (Ti) prepared by using high-purity Nd, Fe, Ti and Si metals as raw materials and adopting an arc melting method in an Ar atmosphere_8.3Fe_91.7)₁₂-Si_zThe sample of (1). Then, the alloy was crushed by a crusher, sieved with a 38 μm mesh sieve, and then subjected to heat treatment (nitriding) at 430 to 520 ℃ in a nitrogen atmosphere for 100 hours. Each sample after heat treatment was subjected to chemical composition analysis and identification of constituent phases, and to saturation magnetization (σ s) and anisotropic magnetic field (H) at the same time_A) The measurement of (1). The results are shown in fig. 2 and 3.

The identification of the constituent phases is performed based on an X-ray diffraction method and measurement of a thermomagnetic curve. The presence or absence of ThMn was confirmed by X-ray diffraction measurement using a Cu tube ball at an output of 15kW₁₂Peaks of the other phases other than the one exist. However, Th₂Mn₁₇Peak of phase and ThMn₁₂Peak group of phaseThis overlap makes it difficult to confirm only by X-ray diffraction. Therefore, the thermomagnetic curve is also used for the identification of the constituent phases. In addition, the thermomagnetic curve was measured by applying a magnetic field of 2kOe to confirm the presence of the corresponding ThMn₁₂Tc (Curie temperature) of the other phases. In the present invention, the term "ThMn" is used₁₂Monophasic organization of phases "means: ThMn could not be observed by the X-ray diffraction method described above₁₂Peaks of phases other than phase; and the corresponding ThMn could not be confirmed by the thermomagnetic curve measurement described above₁₂Tc of the other phases; at the same time, on the high temperature side above Tc, the residual magnetization is 0.05 or less; and may contain unavoidable impurities and unreacted materials which cannot be detected. For example, in the arc furnace melting, a small amount of an unreacted phase (for example, Nd, α -Fe, or the like) may remain due to insufficient thermal uniformity, and inevitable impurities such as Cu originating from the sample holder may be contained. Specific examples related to the identification of the constituent phases are described below on the basis of fig. 4 and 5.

FIG. 4 is a graph showing the results of X-ray diffraction of samples Nos. 4 and 7 and sample No.45 described later. As shown in FIG. 4, only the display ThMn was observed for samples No.4 and No.45₁₂Peak of phase. However, sample No.7 was confirmed to have an α -Fe peak. Further, as described above, Mn₂Th₁₇Peak of phase and ThMn₁₂The peaks of the phases overlap and therefore cannot be distinguished on this curve.

FIG. 5 shows thermomagnetic curves of samples Nos. 4 and 7 and samples Nos. 33 and 45 described below. ThMn exists at about 400 DEG C₁₂Tc of the phase. And Mn₂Th₁₇Tc of the phases (2-17) was confirmed to exist in ThMn as shown in FIG. 5₁₂The low temperature side of Tc phase (sample No. 33). Here, ThMn could not be confirmed₁₂When Tc other than the Tc of the phase exists and the residual magnetization is 0.05 or less on the high temperature side higher than the Tc, the phase is considered to be a single phase. That is, sample No.4 and sample No.45 were unable to confirm ThMn₁₂Tc other than the Tc of the phase exists, and the residual magnetization is 0.05 or less on the high temperature side higher than the Tc, and thus it is identified as ThMn₁₂Monophasic organization of the phases. In addition, sample No.7 was not confirmed to have ThMn₁₂Tc other than that of the phase exists, but on the high temperature side above the Tc, the remanent magnetization exceeds 0.05, and according to FIG. 4, except ThMn₁₂In addition to the phases, the precipitation of α -Fe was also identified. Furthermore, sample No.33 was found to have Mn₂Th₁₇Tc of the phase is present and is higher than ThMn₁₂On the high temperature side of the Tc of the phase, the remanent magnetization exceeds 0.05, and thus other than ThMn can be identified₁₂In addition to the phases, there is Mn₂Th₁₇Phase and precipitation of alpha-Fe.

As described above, in both FIG. 4 (X-ray diffraction) and FIG. 5 (thermomagnetic curve), ThMn is not observed in the constituent phase₁₂Phases other than the phase exist, which is defined as ThMn in this invention₁₂Monophasic organization of the phases.

In addition, saturation magnetization (σ s) and anisotropic magnetic field (H)_A) The magnetization curve is obtained based on a magnetization curve in the easy magnetization axis direction and a magnetization curve in the hard magnetization axis direction, and the magnetization curve is measured using a VSM (vibration sample type magnetometer: stimulating SampleMagnetometer) was performed under the condition of a maximum applied magnetic field of 20 kOe. However, for the convenience of measurement, the saturation magnetization (σ s) is set to the maximum magnetization value on the magnetization curve in the magnetization easy axis direction; and anisotropic magnetic field (H)_A) Then the definition is: the value of the magnetic field in which the tangent of 10kOe on the magnetization curve in the hard-axis direction intersects the value of the saturation magnetization (σ s).

As shown in FIGS. 2 and 3, sample No.6 to which Si was not added had the exception of ThMn₁₂Mn is present in addition to the phases (hereinafter referred to as 1-12 phases)₂Th₁₇Phase (hereinafter referred to as 2-17 phase) and alpha-Fe, especially anisotropic magnetic field (H)_A) Lower. On the contrary, sample Nos. 1 to 5 to which Si was added were found to be a single phase of 1-12 phase, and 1-12 phase transformation was stable. And these 1-12 phase single phase compositions can give a saturation magnetization (. sigma.s) of 130emu/g or more and 50kOe orThe above anisotropic magnetic field (H)_A). However, sample No.7 having an Si content of 2.5 had a-Fe precipitate and had low characteristics. In addition, sample No.8, which contained less than 10 Fe + Ti and 2.5 Si, had saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) Are all significantly reduced. Further, if α -Fe is present as a soft magnetic property, the portion generates an anti-magnetic domain due to a low magnetic field (demagnetizing field). Therefore, the domain inversion of the hard magnetic phase component is easily performed, and as a result, the coercive force is reduced, so that the presence of α -Fe is not desirable for a permanent magnet requiring coercive force.

In the range of sample Nos. 1 to 5, the following tendency was exhibited: the larger the amount of Si, the more the anisotropic magnetic field (H)_A) The higher; conversely, the smaller the amount of Si, the higher the saturation magnetization (. sigma.s).

< Experimental example 2>

Nd- (Ti) composition was prepared in the same manner as in Experimental example 1_8.3Fe_91.7)_x-Si_z-N_1.5The sample (2) is subjected to chemical composition analysis, identification of constituent phases, saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) The measurement of (1). The composition, magnetic properties and phase structure of the sample obtained in experimental example 2 are shown in fig. 6. In addition, the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) of sample Nos. 9 to 11 and 17 to 20_A) The measurement results of (a) are shown in FIGS. 7(a) and 7(b), respectively. Similarly, the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) of sample Nos. 12 to 16, 21 and 22_A) The measurement results of (a) are shown in FIGS. 8(a) and 8(b), respectively. In addition, in Experimental example 2, the relative phase composition of x (Fe amount + Ti amount) and x + z (Fe amount + Ti amount + Si amount), the saturation magnetization (. sigma.s), and the anisotropic magnetic field (H) were confirmed_A) The influence of (3).

As shown in FIGS. 6 to 8, when x is less than 10 (sample Nos. 17 and 21), the saturation magnetization (. sigma.s) is less than 120 emu/g; sample No.17 having z (Si content) as low as 1.1, and anisotropic magnetic field (H)_A) And as low as about 30. On the other hand, when x exceeds 12.5 (sample Nos. 20 and 22), α -Fe is precipitated. In addition, even if x is in the range of 10 to 12.5, if x + z is 12 or less (sample No.18,19) When the saturation magnetization (σ s) is less than 120emu/g, the anisotropic magnetic field (H)_A) And as low as about 30 kOe.

In contrast to the above, when x is in the range of 10 to 12.5 and x + z exceeds 12 (sample Nos. 9 to 16), the following characteristics are exhibited: saturation magnetization (σ s) of 120emu/g or more, and anisotropic magnetic field (H)_A) Is 50kOe or more, and can obtain a monophasic structure of 1 to 12 phases.

< Experimental example 3>

Nd- (Ti) composition was prepared in the same manner as in Experimental example 1_yFe_100-y)-Si_1.0-N_1.5、Nd-(Ti_yFe_100-y)-Si_1.5-N_1.5And Nd- (Ti)_yFe_100-y)-Si_2.0-N_1.5The sample (2) is subjected to chemical composition analysis, identification of constituent phases, saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) The measurement of (1). The composition, magnetic properties and phase structure of the sample obtained in experimental example 3 are shown in fig. 9. In addition, the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) of samples Nos. 23 to 25 and 33 to 35_A) The measurement results of (a) are shown in FIGS. 10(a) and 10(b), respectively. Similarly, the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) of sample Nos. 26 to 28, 36 and 37_A) The measurement results of (A) are shown in FIGS. 11(a) and 11(b), respectively, and the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) of samples No.29 to 32, 38_A) The measurement results of (a) are shown in FIGS. 12(a) and 12(b), respectively.

In addition, in Experimental example 3, the relative phase composition of y (Ti content), saturation magnetization (. sigma.s), and anisotropic magnetic field (H) were confirmed_A) The influence of (3).

As shown in FIGS. 9 to 12, when z (Si amount) is any one of 1.0, 1.5 and 2.0, and y (Ti amount) is less than (8.3-1.7 xz), α -Fe and further 2-17 phase are precipitated (sample Nos. 33, 34 and 36 to 38). On the other hand, when y (Ti content) is 12.5 and exceeds 12.3, the saturation magnetization (. sigma.s) is reduced to less than 120emu/g (sample No. 35).

And the aboveIn contrast, when y (Ti content) is in the range of (8.3-1.7 xz) to 12.3, the sample has a single-phase structure of 1-12 phases, that is, a single-phase structure of a hard magnetic phase, and a saturation magnetization (. sigma.s) of 130emu/g or more, further 140emu/g or more, and an anisotropic magnetic field (H) of 50kOe or more, further 55kOe or more_A) (sample Nos. 23 to 32).

< Experimental example 4>

Nd- (Ti) composition was prepared in the same manner as in Experimental example 1_8.3Fe_91.7)₁₂-Si_2.0-N_vThe sample (2) is subjected to chemical composition analysis, identification of constituent phases, saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) The measurement of (1). The composition, magnetic properties and phase structure of the sample obtained in experimental example 4 are shown in fig. 13. In addition, the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) of sample Nos. 39 to 44_A) The measurement results of (a) are shown in fig. 14(a) and 14(b), respectively.

In addition, in experimental example 4, the relative phase composition of v (amount of N), saturation magnetization (σ s), and anisotropic magnetic field (H) were confirmed_A) The influence of (3).

As shown in fig. 13 and 14, when v (amount N) is 0, the saturation magnetization (σ s) and the anisotropic magnetic field (H) are set to be equal to each other_A) All were low (sample No. 43); on the other hand, when v (N content) is 3.5 and exceeds 3, α -Fe is precipitated (sample No. 44).

In contrast to the above, when v (amount N) is in the range of 0.1 to 3, the sample has a single-phase structure of 1 to 12 phases, in other words, a single-phase structure of a hard magnetic phase, and a saturation magnetization (σ s) of 120emu/g or more and an anisotropic magnetic field (H) of 30kOe or more can be obtained_A) (sample Nos. 39 to 42). From saturation magnetization (σ s) and anisotropic magnetic field (H)_A) In view of (2), v (amount of N) is preferably set to 0.5 to 2.7, more preferably 1.0 to 2.5.

< Experimental example 5>

And experimentsExample 1 samples as shown in fig. 15 were prepared in the same manner, and identification of the constituent phases, saturation magnetization (σ s), and anisotropic magnetic field (H) were performed_A) The results of the measurement of (2) are shown in FIG. 15.

In addition, Experimental example 5 was conducted to confirm Nd- (Ti)_8.3Fe_91.7-wCo_w)₁₂-Si_z-N_1.5(iii) dependence of w (Co amount) in (1).

As shown in fig. 15, it is understood that when z (Si amount) is any one of 0.25 and 1.0, if w (Co amount) is increased, saturation magnetization (σ s) and anisotropic magnetic field (H) are increased_A) The effect is increased and peaks at w (Co amount) of about 20. Therefore, if the price of Co is also considered to be expensive, w (Co amount) is preferably 30 or less, and more preferably 10 to 25. When w (Co amount) is within this range, the structure is a single phase of 1 to 12 phases.

< Experimental example 6>

The alloy composition is Nd- (Ti) prepared by using high-purity Nd, Fe, Ti and Si metals as raw materials and adopting an arc melting method in an Ar atmosphere_8.3Fe_91.7-wCo_w)₁₂-Si_zThe sample of (1). Then, the alloy is crushed by a crusher, sieved by a sieve having a mesh of 38 μm, mixed with C powder having an average particle diameter of 1 μm or less, and subjected to heat treatment at 400 to 600 ℃ for 24 hours in an Ar atmosphere. The samples after the heat treatment were analyzed for chemical composition and identified for constituent phases, and subjected to saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) The results of the measurement of (2) are shown in FIG. 16.

As shown in FIG. 16, by adding C instead of N, it is possible to obtain a 1-12 phase single-phase structure, and at the same time, it is possible to obtain a saturation magnetization (. sigma.s) of 120emu/g or more and an anisotropic magnetic field (H) of 30kOe or more_A). In this case, C and N exert the same effect.

In addition, even in the case of using Pr to replace 1 to 25% of Nd, the same results as those of other samples were obtained.

[ example 2]

The results of the experiments carried out to confirm the change in magnetic properties due to the substitution of a part of Nd with Zr or Hf (experimental examples 7 to 14) are shown as example 2. In addition, in examples 7 to 13, a part of Nd was replaced with Zr; experimental example 14A part of Nd was replaced with Hf.

< Experimental example 7>

The alloy composition of Nd is prepared by using high-purity Nd, Zr, Fe, Ti and Si metals as raw materials and adopting an arc melting method in an Ar atmosphere_1-xZr_x(Ti_8.3Fe_91.7)₁₂Si_1.0The sample of (1). Subsequently, the pulverization and the heat treatment (nitriding) were carried out in the same process flow as in example 1. For each sample after heat treatment, analysis of chemical composition and identification of constituent phase were performed, and saturation magnetization (σ s) and anisotropic magnetic field (H) were performed under the same conditions as in example 1_A) The results of the measurement of (2) are shown in FIG. 17.

As shown in FIG. 17, by substituting a part of Nd with Zr, a saturation magnetization (. sigma.s) of 140emu/g or more can be obtained. The effect of improving the saturation magnetization (σ s) due to Zr shows a peak when the Zr amount (u) is 0.05, and thereafter the saturation magnetization (σ s) tends to decrease as the Zr amount (u) increases; when the Zr content (u) reached 0.20, the saturation magnetization (. sigma.s) was lower than that of the sample containing no Zr. In addition, when the Zr content (u) is in the range of 0.02 to 0.15, ThMn is obtained₁₂Monophasic organization of phases (hereinafter referred to as 1-12 phases).

From the above, in the general formula: r1_1-uR2_u(TiyFe_100-y-wCo_w)_xSi_zA_vIn the above range, the Zr content (u) is preferably in the range of 0.01 to 0.18, more preferably in the range of 0.04 to 0.06.

For each sample after heat treatment, the constituent phases were identified by X-ray diffraction. Conditions of X-ray diffraction and1 example likewise, the presence or absence of ThMn was confirmed₁₂Phase and other phase peaks. As other phases, alpha-Fe, Mn are mentioned₂Th₁₇Phase and nitride of Nd. ThMn for higher magnetic properties₁₂Main diffraction pattern other than phase vs. ThMn₁₂The main diffraction pattern of the phase preferably has a peak intensity ratio of 50% or less. Specific examples of identification of the constituent phases will be described based on fig. 18 and 19.

FIG. 18 is a graph showing the results of X-ray diffraction measurements of samples No.63, 91 and 105 described later, and only the results of ThMn observation of samples No.63 and 91₁₂Peak of phase. In contrast, the sample 105 was confirmed to have an α -Fe peak. This can be interpreted as: since the sample 105 contained an excessive amount of N, ThMn was observed₁₂The phases are decomposed, followed by the precipitation of alpha-Fe. This was determined from ThMn of sample 105₁₂The peak intensity of the phase is reduced and on the other hand the peak intensity of α -Fe is increased.

FIG. 19 is an enlarged view of the vicinity of the diffraction angle at which the α -Fe peak is generated. Around this angle, ThMn₁₂The phase peak is adjacent to the α -Fe peak. Only ThMn was observed in sample No.63₁₂Peak of phase. In addition, ThMn was observed in sample No.91₁₂Two peaks of phase and alpha-Fe, but in the case of a small amount of alpha-Fe, the influence on the characteristics is small. On the other hand, sample No.105 almost observed only the peak of α -Fe. Further, as is clear from FIG. 18, the main diffraction pattern of α -Fe is relative to ThMn observed at around 42 °₁₂The peak intensity ratio of the main diffraction pattern of the phase is 50% or more, and thus when a large amount of α -Fe is precipitated, the deterioration of the characteristics becomes more remarkable.

< Experimental example 8>

Nd was produced in the same process flow as in Experimental example 7_0.95Zr_0.05(Ti_8.3Fe_91.7)₁₂Si_uN_1.5The sample (2) was subjected to chemical composition analysis, identification of constituent phases, saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) The results of the measurement of (2) are shown in FIG. 20.

In addition, in experimental example 8, the phase composition of the Si amount (z), the saturation magnetization (σ s), and the anisotropic magnetic field (H) were confirmed_A) The influence of (3).

In addition to the 1-12 phases, Mn was present in sample No.69 to which Si was not added₂Th₁₇Phase (hereinafter referred to as 2-17 phase) and alpha-Fe phase, especially anisotropic magnetic field (H)_A) Lower. In contrast, sample Nos. 70 to 73 containing Si were found to be 1-12 phase single phase, and 1-12 phase transformation was stable. And these 1-12 phase single phase compositions can obtain a saturation magnetization (. sigma.s) of 140 or 145emu/g or more and an anisotropic magnetic field (H) of 50 or 55kOe or more_A). However, sample No.74 having an Si content of 2.5 precipitated a large amount of α -Fe, and the characteristics were degraded. Further, if α -Fe is present as a soft magnetic property, the portion generates an anti-magnetic domain due to a low magnetic field (demagnetizing field). Therefore, the domain inversion of the hard magnetic phase component is easily performed, and as a result, the coercive force is reduced, so that the presence of α -Fe is not desirable for a permanent magnet requiring coercive force.

In sample Nos. 70 to 73, the following tendency was observed: the larger the amount of Si, the more the anisotropic magnetic field (H)_A) The higher; conversely, the smaller the amount of Si, the higher the saturation magnetization (. sigma.s).

< Experimental example 9>

Nd was produced in the same process flow as in Experimental example 7_0.95Zr_0.05(Ti_8.3Fe_91.7)_xSi_0.5N_1.5、Nd_0.95Zr_0.05(Ti_8.3Fe_91.7)_xSi_1.0N_1.5And Nd_0.95Zr_0.05(Ti_8.3Fe_91.7)_xSi_1.5N_1.5The sample (2) was subjected to chemical composition analysis, identification of constituent phases, saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) The results of the measurement of (2) are shown in FIG. 21.

In addition, Experimental example 9 is to confirm the Fe content + Co contentA relative phase composition of + Ti amount (x), Fe amount + Co amount + Ti amount + Si amount (x + z), saturation magnetization (σ s), and anisotropic magnetic field (H)_A) The influence of (3).

As shown in FIG. 21, when the Fe amount + Co amount + Ti amount (x) is less than 11 (sample Nos. 81, 83, 84, and 86), the saturation magnetization (. sigma.s) is less than 140 emu/g. On the other hand, when x reaches 13 (sample No.85), α -Fe is precipitated in a large amount, resulting in deterioration of the properties. In addition, even if x is in the range of 11 to 12.5, and x + z, that is, when (the molar ratio of Fe + the molar ratio of Co + the molar ratio of Ti + the molar ratio of Si)/(the molar ratio of R1+ the molar ratio of R2) is 11.6 and is 12 or less (sample No.82), the saturation magnetization (. sigma.s) shows a value of 140emu/g or more, the anisotropic magnetic field (H.sub.magnetic field) is not less than_A) But stays at a value of 40kOe or less.

In contrast to the above, sample Nos. 75 to 80, in which x is in the range of 11 to 12.8 and x + z exceeds 12, had a saturation magnetization (. sigma.s) of 140emu/g or more and an anisotropic magnetic field (H) of 50kOe or more_A)。

< Experimental example 10>

Nd was produced in the same process flow as in Experimental example 7_0.95Zr_0.05(Ti_yFe_100-y)₁₂Si_1.0N_1.5、Nd_0.95Zr_0.05(Ti_yFe_100-y)₁₂Si_1.5N_1.5And Nd_0.95Zr_0.05(Ti_yFe_100-y)₁₂Si_2.0N_1.5The sample (2) was subjected to chemical composition analysis, identification of constituent phases, saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) The results of the measurement of (2) are shown in FIG. 22.

In addition, in Experimental example 10, the phase composition of the Ti content (y), the saturation magnetization (. sigma.s), and the anisotropic magnetic field (H) were confirmed_A) The influence of (3).

When the Si amount (z) is any one of 1.5 and 2.0, if the Ti amount (y) is less than 5.0, alpha-Fe is precipitated and 2-17 phase is precipitatedSaturation magnetization (σ s) and anisotropic magnetic field (H)_A) The sample remained at a low value (sample No.94, 99). On the other hand, when the Ti content (y) is 12.5 and exceeds 12.3, the saturation magnetization (. sigma.s) is reduced to less than 130emu/g (sample No. 90).

In contrast to the above, sample Nos. 87 to 89, 91 to 93, 95 to 98 having Ti content (y) within the range of 5 to 12.3 had a single-phase structure of 1 to 12 phases, that is, a single-phase structure of hard magnetic phase, and could obtain saturation magnetization (. sigma.s) of 140 or 150emu/g or more and an anisotropic magnetic field (H) of 50 or 55kOe or more_A)。

< Experimental example 11>

Nd was produced in the same process flow as in Experimental example 7_0.95Zr_0.05(Ti_yFe_100-y)₁₂Si_1.0N_vThe sample (2) was subjected to chemical composition analysis, identification of constituent phases, saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) The results of the measurement of (2) are shown in FIG. 23.

In addition, in experimental example 11, the phase composition of the N amount (v), the saturation magnetization (σ s), and the anisotropic magnetic field (H) were confirmed_A) The influence of (3).

As shown in FIG. 23, when the N amount (v) is 0, the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) are set_A) All decreased (sample No. 100).

In contrast to the above, sample Nos. 101 to 104 having an N amount (v) in the range of 1 to 3 had a single-phase structure of 1 to 12 phases, that is, a single-phase structure of a hard magnetic phase, and could obtain a saturation magnetization (. sigma.s) of 140emu/g or more and an anisotropic magnetic field (H) of 45 or 50kOe or more_A). From saturation magnetization (σ s) and anisotropic magnetic field (H)_A) In view of (1), the amount (v) of N is preferably set to 0.5 to 2.7, more preferably 1.0 to 2.5.

< Experimental example 12>

In the same manner as in Experimental example 7The composition of the technological process is Nd_0.95Zr_0.05(Ti_8.3Fe_91.7-wCo_w)₁₂Si_0.25N_1.5、Nd_0.95Zr_0.05(Ti_8.3Fe_91.7-wCo_w)₁₂Si_1.0N_1.5The samples of (1) were analyzed for the constituent phases, and the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) were measured_A) The results of the measurement of (2) are shown in FIG. 24.

In addition, in experimental example 12, the relative phase composition of the Co amount (w), the saturation magnetization (σ s), and the anisotropic magnetic field (H) were confirmed_A) The influence of (3).

As shown in fig. 24, it is found that when the Si amount (z) is any one of 0.25 and 1.0, if the Co amount (w) is increased, the saturation magnetization (σ s) and the anisotropic magnetic field (H) are increased_A) The effect is increased and peaks at w (Co amount) of about 20. Therefore, if the price of Co is also considered to be expensive, w (Co amount) is preferably 30 or less, and more preferably 10 to 25. When w (Co amount) is within this range, the structure is a single phase of 1 to 12 phases.

< Experimental example 13>

The alloy with Nd component is prepared by using high-purity Nd, Zr, Fe, Ti and Si metals as raw materials and adopting an arc melting method in an Ar atmosphere_0.95Zr_0.05(Ti_8.3Fe_91.7-wCo_w)₁₂Si_zThe sample of (1). Then, the alloy is crushed by a crusher, sieved by a sieve having a mesh of 38 μm, mixed with C powder having an average particle diameter of 1 μm or less, and subjected to heat treatment at 400 to 600 ℃ for 24 hours in an Ar atmosphere. Each sample after the heat treatment was subjected to chemical composition analysis and identification of constituent phases, and simultaneously subjected to saturation magnetization (σ s) and anisotropic magnetic field (H)_A) The measurement of (1). The results are shown in FIG. 25.

As shown in FIG. 25, by adding C instead of N, a 1-12 phase single-phase structure can be obtained, and at the same time, a single-phase structure can be obtainedSaturation magnetization (σ s) to 140 or 150emu/g or more and anisotropic magnetic field (H) of 40kOe or more_A). In this case, C and N exert the same effect.

< Experimental example 14>

The result of the experiment performed to confirm the change in magnetic properties due to the replacement of a part of Nd with Hf is shown as experimental example 14.

Nd was produced in the same process flow as in Experimental example 7_1-uHf_u(Ti_8.3Fe_91.7)₁₂Si_1.0N_1.5The sample (2) was subjected to chemical composition analysis, identification of constituent phases, saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) The measurement of (1). The results are shown in FIG. 26.

As shown in fig. 26, Hf has the same effect as Zr.

[ example 3 ]

In order to confirm the variation of c/a with Si content, the results of the experiments (Experimental examples 15 and 16) performed are shown as example 3.

< Experimental example 15>

The alloy composition is Nd- (Ti) prepared by using high-purity Nd, Fe, Ti and Si metals as raw materials and adopting an arc melting method in an Ar atmosphere_8.2Fe_91.8)_11.9-Si_zAnd Nd- (Ti)_8.3Fe_91.7)₁₂-Si_zThe sample of (1). Then, the alloy was crushed by a crusher, sieved with a 38 μm mesh sieve, and then subjected to heat treatment (nitriding) at 430 to 520 ℃ in a nitrogen atmosphere for 100 hours. Each sample after the heat treatment was subjected to chemical composition analysis and identification of the constituent phase, and saturation magnetization (σ s) and anisotropic magnetic field (H) were performed under the same conditions as in example 1_A) The results of the measurement of (2) are shown in FIG. 27.

In addition, the phase structure was identified by X-ray diffraction and thermomagnetic curve measurement in the same manner as in example 1.

As shown in FIG. 27, it is found that the magnetic properties, particularly the anisotropic magnetic field (H) of samples 121 to 126 having a large c/a are larger than that of 0.552 of sample 129 not added with Si_A) Is improved. However, referring to fig. 28, the following tendency is also observed: on the one hand, as the lattice constant of the a-axis decreases to a predetermined range, the anisotropic magnetic field (H)_A) With a consequent increase, and on the other hand with a decrease in the saturation magnetization (σ s). In addition, the sample No.131 having a large amount of Si precipitated α -Fe, and also had saturation magnetization (. sigma.s) and anisotropic magnetic field (H)_A) Both decrease. The saturation magnetization (. sigma.s) of sample No.130 to which N was not added was low. In addition, the saturation magnetization (σ s) and the anisotropic magnetic field (H) of the sample No.129 containing N but not containing Si and the sample No.130 containing Si but not containing N_A) The levels of (c) can be seen: the saturation magnetization (. sigma.s) and the anisotropy field (H) of samples No.121 to 126 of the present invention_A) The magnetic properties of the alloy are significantly improved by containing both Si and N.

Fig. 28 shows the thermomagnetic curves of the compositions of sample nos. 127, 128 and 132 of fig. 27, and it is found that the Tc is present in the vicinity of 430 ℃ in sample nos. 127 and 128, and the presence of Tc other than this is not confirmed. Therefore, it was confirmed that sample Nos. 127 and 128 were ThMn₁₂Monophasic organization of the phases. Sample No.132 was confirmed to have Tc corresponding to 1 st at around 400 ℃ and to have a magnetization of 20% at 450 ℃ corresponding to room temperature. This indicates that sample No.132 has a magnetic phase with a Tc of 450 ℃ or higher. When the measurement temperature was increased, magnetization was lost in the vicinity of 770 ℃, and the presence of phase 2 could be confirmed. From this result and the result of X-ray diffraction, it was confirmed that the 2 nd phase was α -Fe.

< Experimental example 16>

The composition shown in fig. 29 was obtained in the same manner as in experimental example 15, and saturation magnetization (σ s) and anisotropic magnetic field (H) were performed in the same manner as in experimental example 15 for this composition_A) The measurement of (2) was performed simultaneously with the measurement of the constituent phases, and the results are shown together in the figure29。

As shown in FIG. 29, sample Nos. 133 to 137, in which the amount (x) of Fe + Ti, i.e., the ratio of Fe + Ti to R was in the range of 10 to 12.5, exhibited high magnetic characteristics, saturation magnetization (. sigma.s) of 120 or 130emu/g or more, and anisotropic magnetic field (H.sub._A) Is 55kOe or more. And the composition based on sample Nos. 133 to 137 is ThMn₁₂Monophasic organization of the phases. In contrast, sample No.138, in which the ratio of Fe + Ti to R was 12.7, was found to have the exception of ThMn₁₂In addition to the compounds, the precipitation of α -Fe was also confirmed. In samples No.133 to 137, when the ratio of Fe + Ti to R was small, the structure was a single phase but the saturation magnetization (. sigma.s) and the anisotropic magnetic field (H) were observed_A) Both decrease. From this tendency, the ratio of Fe + Ti to R is preferably set to 10 or more.

[ 4 th example ]

The examples (1 st to 3 rd) shown above relate to a hard magnetic composition, and example 4 shows a specific example relating to a permanent magnet powder.

< Experimental example 17>

Raw materials weighed to have the following compositions were melted and quenched in an Ar atmosphere under the following quenching conditions.

The alloy obtained was in the form of a flake having a thickness of 20 μm, and was subjected to a heat treatment at 800 ℃ for 2 hours in an Ar atmosphere.

Then, the pulverized powder was pulverized with a pulverizer to a size that can pass through a 75 μm sieve, and subjected to nitriding treatment. The nitriding conditions are as follows: at 400 ℃ for 64 hours, N₂Gas flow (atmospheric pressure).

Composition: nd (neodymium)₁Fe_9.15Co_2.0Ti_0.85Si_0.2

Single roll method (roll material: Cu)

Nozzle hole diameter: phi 1mm

Ejection gas pressure: 0.5kg/cm²

Molten metal temperature: 1400 deg.C

Peripheral speed of roller (Vs): 15. 25, 50 and 75m/s

The structure of the phase was observed by XRD (X-Ray diffraction apparatus) for the rapidly solidified flakes (samples) and the heat-treated samples, and the results are shown in FIGS. 30 and 31. Fig. 30 shows the observation result of the sample after rapid solidification, and fig. 31 shows the observation result of the sample after heat treatment.

As shown in FIG. 30, ThMn was observed in the samples obtained at peripheral speeds (Vs) of the rolls of 15m/s and 25m/s₁₂The peak of the phase exists. On the contrary, ThMn was not observed in the samples obtained at the peripheral speeds (Vs) of the rollers of 50m/s and 75m/s₁₂The phase peaks are present, but are diffraction patterns characteristic of amorphousness.

As shown in FIG. 31, ThMn was confirmed at all peripheral speeds after the heat treatment₁₂The phase is the main phase.

FIG. 32 is a photograph showing the results of observation of a sample heat-treated at a peripheral speed (Vs) of a roller of 25m/s by a TEM (Transmission Electron microscope). FIG. 33 is a photograph showing the results of TEM observation of a structure obtained by heat-treating a sample at a peripheral speed (Vs) of a roller of 75 m/s.

As shown in fig. 32 and 33, it was confirmed that the sample after heat treatment exhibited an extremely fine crystal structure. However, the following differences exist in the structure after the heat treatment depending on the peripheral speed (Vs) of the roller. In a sample obtained at a peripheral speed (Vs) of a roll of 25m/s, many crystals having a particle size of about 25nm were observed, and the maximum particle size was about 50 nm. In contrast, a sample obtained at a peripheral speed (Vs) of the roller of 75m/s showed many crystals having a particle size of about 10nm, and the maximum particle size was about 100 nm.

Next, the magnetic properties (applied magnetic field: 20kOe) of the samples after rapid solidification, after heat treatment and after nitriding treatment were measured by VSM. The results are shown in FIG. 34. The N content of the sample after nitriding treatment was as follows.

When the peripheral speed (Vs) of the roller is 25 m/s: 2.93 wt%

When the peripheral speed (Vs) of the roller is 75 m/s: 2.79 wt%

As shown in fig. 34, it was confirmed that both the coercive force (Hcj) and the residual magnetization (σ s) were improved by nitriding after the heat treatment, and that sufficient characteristics were obtained as the permanent magnet powder. Fig. 34 also shows the results of measurement of the magnetic properties of the powders of the following comparative examples, but the coercive force (Hcj) and the residual magnetization (σ s) both remained at values lower than those of the examples.

Comparative example: the raw materials were weighed to have the same composition (Nd) as in the present example₁Fe_9.15Co_2.0Ti_0.85Si_0.2) Then, the alloy was melted by a high-frequency melting method and poured into a water-cooled Cu mold to prepare an alloy (alloy thickness: 10 mm). The alloy was pulverized by a pulverizer in the same manner as in example, and then heat treatment and nitriding treatment were performed in the same manner as in example to obtain a powder.

Next, for the powder subjected to nitriding treatment (peripheral speed (Vs) of the roller: 50m/s), 3 wt% of an epoxy resin was mixed and stirred, and then, in a metal mold having a cylindrical cavity of 10mm in diameter, 6 tons/cm²The molding pressure of (3) is adjusted, and the molded body is cured at 150 ℃ for 4 hours to obtain a bonded magnet. The magnetic properties of the bonded magnet were measured with a B-H tracer (tracer) (applied magnetic field: 25kOe), and the results were as follows:

Br＝6700G、Hcj＝7980Oe、(BH)_max＝8.5MGOe

< Experimental example 18>

After the rapidly solidified alloy having the composition shown in fig. 35 was produced, heat treatment and nitriding treatment were performed. The conditions for the rapid solidification, heat treatment and nitriding treatment are as follows. The results of measuring the magnetic properties after the nitriding treatment are shown in FIG. 35.

Rapid solidification

Single roll method (roll material: Cu)

Nozzle hole diameter: phi 1mm

Ejection gas pressure: 0.5kg/cm²

Melting temperature: 1400 deg.C

Peripheral speed of roller (Vs): 50m/s

Heat treatment

Held at 800 ℃ for 2 hours in an Ar atmosphere.

Nitriding treatment-

In N₂The temperature was maintained at 400 ℃ for 64 hours in a gas stream (atmospheric pressure).

As shown in fig. 35, it can be confirmed that: the nitriding treatment after the heat treatment is effective for obtaining a permanent magnet powder having high magnetic characteristics.

According to the present invention, it is possible to provide a rare earth element that can easily generate ThMn even when Nd is used as the rare earth element₁₂Hard magnetic compositions of phases. In particular, according to the present invention, even if Nd is 100 mol%, a compound formed by ThMn can be obtained₁₂A single-phase structure of the phase, in other words, a hard magnetic composition composed of a single-phase structure of a hard magnetic phase.

Further, according to the present invention, Si which anisotropically shrinks a crystal lattice and N which isotropically expands a crystal lattice are present as interstitial atoms in the intermetallic compound, and the ratio of R to T is about 12, and by using such an intermetallic compound, a hard magnetic composition having a single-phase structure with high saturation magnetization and high anisotropic magnetic field can be obtained.

Further, according to the present invention, it is possible to provide a rare earth element even when Nd is used as a rare earth elementThMn can be easily produced even in the case of a soil-based element₁₂Permanent magnet powder of phase and method for producing the same. Further, according to the present invention, a bonded magnet using such a permanent magnet powder can be obtained.

Claims (25)

1. A hard magnetic composition characterized by: the hard magnetic composition is represented by the general formula R (Fe)_100-y-wCo_wTi_y)_xSi_zA_vAnd has a composition in which the molar ratio of the formula satisfies: x is 10 to 12.5, y is (8.3-1.7 xz) to 12.3, z is 0.1 to 2.3, v is 0.1 to 3, w is 0 to 30, and (Fe + Co + Ti + Si)/R > 12;

and consists of ThMn₁₂A single phase structure of a phase of a type crystal structure;

in the above formula, R is at least 1 element selected from rare earth elements, wherein the rare earth elements are in the concept of containing Y, 50 mol% or more of R is Nd, and A is N and/or C.

2. The hard magnetic composition of claim 1, wherein: 70 mol% or more of R is Nd.

3. The hard magnetic composition of claim 1, wherein: a part of the R is replaced by Zr and/or Hf.

4. A hard magnetic composition characterized by: the hard magnetic composition is represented by the general formula R1_1-uR2_u(Fe_100-y-wCo_wTi_y)_xSi_zA_vAnd has a composition in which the molar ratio of the general formula satisfies: u is 0.18 or less, y is 4.5 to 12.3, x is 11 to 12.8, z is 0.1 to 2.3, v is 0.1 to 3, w is 0 to 30, and (Fe + Co + Ti + Si)/(R1+ R2) > 12;

and consists of ThMn₁₂A single phase structure of a phase of a type crystal structure;

in the above formula, R1 is at least 1 element selected from rare earth elements, wherein the rare earth elements are concept containing Y, 50 mol% or more of R1 is Nd, R2 is Zr and/or Hf, and A is N and/or C.

5. The hard magnetic composition of claim 4, wherein: and u is 0.04-0.06.

6. The hard magnetic composition according to claim 1 or 4, wherein: and A is N.

7. The hard magnetic composition according to claim 1 or 4, wherein: and x is 11-12.5.

8. The hard magnetic composition according to claim 1 or 4, wherein: and z is 0.2-2.0.

9. The hard magnetic composition according to claim 1 or 4, wherein: and v is 0.5-2.5.

10. The hard magnetic composition according to claim 1 or 4, wherein: and w is 10-25.

11. A hard magnetic composition characterized by: the hard magnetic composition consists of an R-Ti-Fe-Si-A compound or an R-Ti-Fe-Co-Si-A compound and has ThMn₁₂A hard magnetic phase of a crystal structure having a saturation magnetization σ s of 120emu/g or more and an anisotropic magnetic field H_AIs 30kOe or more and,

in the above formula, R is at least 1 element selected from rare earth elements, wherein the rare earth elements are in the concept of containing Y, 80 mol% or more of R is Nd, and A is N and/or C.

12. The hard magnetic composition of claim 11, wherein: the anisotropic magnetic field H_AIs 40kOe or more.

13. The hard magnetic composition of claim 11, wherein: the saturation magnetization σ s is 130emu/g or more.

14. A hard magnetic composition characterized by: the hard magnetic composition is composed of a single-phase structure of an intermetallic compound in which the molar ratio of R to T is about 1: 12, and Si and A exist as interstitial elements between crystal lattices of the intermetallic compound, wherein R is at least 1 element selected from rare earth elements containing Y, T is a transition metal element containing Fe and Ti as essential components, and A is N and/or C.

15. The hard magnetic composition of claim 14, wherein: when the ratio of the lattice constant of the c-axis and the lattice constant of the a-axis of the crystal lattice of the intermetallic compound is set to c1/a1, ThMn based on American society for testing and materials ASTM₁₂When the ratio of the lattice constant of the c-axis to the lattice constant of the a-axis of the crystal lattice of the type compound is c2/a2, c1/a 1> c2/a2, wherein c2/a2 is 0.558.

16. The hard magnetic composition of claim 14, wherein: the lattice is anisotropically contracted by Si and isotropically expanded by A, giving c1/a 1> c2/a 2.

17. The hard magnetic composition of claim 14, wherein: the molar ratio of R to T is 1: 10-1: 12.5.

18. A permanent magnet powder characterized in that: the magnet powder is represented by the general formula R (Fe)_100-y-wCo_wTi_y)_xSi_zA_vForming;

and the magnet powder has a composition in which the molar ratio of the general formula satisfies: x is 10 to 12.8, y is (8.3-1.7 xz) to 12.3, z is 0.1 to 2.3, v is 0.1 to 3, w is 0 to 30, and (Fe + Co + Ti + Si)/R > 12;

and consists of an aggregate of particles having an average crystal grain diameter of 200nm or less;

and the particles consist essentially of particles having ThMn₁₂A single phase structure of a phase of a type crystal structure;

in the above formula, R is at least 1 element selected from rare earth elements, wherein the rare earth elements are in the concept of containing Y, 50 mol% or more of R is Nd, and A is N and/or C.

19. The permanent magnet powder according to claim 18, wherein: nd is 70 mol% or more of R.

20. A method for manufacturing a permanent magnet powder, characterized by: first, a catalyst of the general formula R (Fe)_100-y-wCo_wTi_y)_xSi_zA powder constituted by a powder subjected to rapid solidification treatment, wherein the powder has a composition such that the molar ratio of the general formula satisfies: x is 10 to 12.8, y is (8.3-1.7 xz) -12.3, z is 0.1 to 2.3, w is 0 to 30, and (Fe + Co + Ti + Si)/R > 12; secondly, heat treatment is carried out on the powder for 0.5 to 120 hours at the temperature of 600 to 850 ℃ in an inert atmosphere; then, the powder subjected to the heat treatment is subjected to nitriding treatment or carbonizing treatment, thereby obtaining a powder substantially having ThMn₁₂A powder composed of a single-phase structure of a phase of a type crystal structure;

in the above formula, R is at least 1 element selected from rare earth elements, wherein the rare earth elements are in the concept of containing Y, and 50 mol% or more of R is Nd.

21. The method for producing a permanent magnet powder according to claim 20, wherein: the powder subjected to the rapid solidification treatment has a structure of any one of an amorphous phase, a mixed phase of an amorphous phase and a crystalline phase, and a crystalline phase.

22. The method for producing a permanent magnet powder according to claim 20, wherein: the rapid cooling solidification treatment is carried out by adopting a single-roller method, and the peripheral speed of the used roller is 10-100 m/s.

23. The method for producing a permanent magnet powder according to claim 20, wherein: the heat treatment is to crystallize the amorphous phase or to adjust the grain size of crystal grains constituting the crystalline phase.

24. A bonded magnet comprising a permanent magnet powder and a resin phase for bonding the permanent magnet powder, wherein: the crystalline hard magnetic particles constituting the permanent magnet powder are represented by the general formula R (Fe)_100-y-wCo_wTi_y)_xSi_zA_vAnd has a composition in which the molar ratio of the general formula satisfies: x is 10 to 12.8, y is (8.3-1.7 xz) to 12.3, z is 0.1 to 2.3, v is 0.1 to 3, w is 0 to 30, and (Fe + Co + Ti + Si)/R > 12;

and the hard magnetic particles consist of particles having ThMn₁₂A single phase structure of a phase of a type crystal structure;

in the above formula, R is at least 1 element selected from rare earth elements, wherein the rare earth elements are in the concept of containing Y, 50 mol% or more of R is Nd, and A is N and/or C.

25. The bonded magnet of claim 24, wherein: the hard magnetic particles have an average crystal grain diameter of 200nm or less.