JP3891307B2 - Nd-Fe-B rare earth permanent sintered magnet material - Google Patents

Description

The present invention relates to a Nd—Fe—B rare earth permanent sintered magnet material.

Rare earth permanent magnets are widely used in the field of electrical and electronic equipment because of their excellent magnetic properties and economy, and in recent years, their performance is increasingly required.
In order to improve the properties of the R—Fe—B rare earth permanent magnet, it is necessary to increase the proportion of the R ₂ Fe ₁₄ B ₁ phase that is the main phase component in the alloy. This is synonymous with reducing the Nd-rich phase, which is a nonmagnetic phase. Therefore, it is necessary to reduce the oxygen, carbon, and nitrogen concentrations of the alloy so that the Nd-rich phase is not oxidized, carbonized, or nitrided as much as possible.
However, if the oxygen concentration in the alloy is reduced, abnormal grain growth is likely to occur in the sintering process, and although Br is high, iHc is low and (BH) max is insufficient, resulting in a magnet with poor squareness.

As described in Japanese Patent Application Laid-Open No. 2002-75717 (Patent Document 1), the present inventor reduced the oxygen concentration during the manufacturing process in order to improve the magnetic characteristics, and reduced the oxygen concentration in the alloy. Even if it is lowered, the optimum sintering temperature range is remarkably expanded by depositing the ZrB compound, NbB compound or HfB compound finely and uniformly in the magnet, and high performance Nd-Fe- with little abnormal grain growth. It was reported that production of B-based rare earth permanent magnet materials became possible.
Furthermore, the present inventor tried to manufacture a magnet alloy by using an inexpensive raw material having a large carbon concentration. As a result, iHc was remarkably lowered, the squareness was poor, and the product could not be used. Only the characteristic which becomes is obtained.
This significant decrease in magnetic properties is due to the fact that existing ultra-high performance magnets have the minimum amount of R-rich phase, so even with a slight increase in carbon concentration, much of the non-oxidized R-rich phase is carbide. This is considered to be because the R-rich phase necessary for liquid phase sintering is extremely reduced.
It has been found that the Nd-based sintered magnets that have been industrially produced so far start to decrease in coercive force when the carbon concentration exceeds approximately 0.05%, and cannot be used as a product when it exceeds approximately 0.1%. ing.

JP 2002-75717 A

The present invention has been made in view of the above circumstances, and an Nd—Fe—B rare earth having excellent magnetic properties, in which the growth of abnormal grains is suppressed, the optimum sintering temperature range is widened even at high carbon and low oxygen concentrations. An object is to provide a permanent sintered magnet material.

As a result of intensive studies to solve the above problems, the present inventor has found that an M-B compound is contained in an R—Fe—B rare earth permanent sintered magnet having a high carbon concentration containing Co, Al, and Cu. And at least two of M-B-Cu compounds and M-C compounds (M is one or more of Ti, Zr, and Hf) and further an R oxide precipitates in the alloy structure. In addition, the average particle size of the precipitated compound is 5 μm or less, and the maximum distance between the compounds deposited adjacent to each other in the alloy structure is uniformly dispersed and precipitated to 50 μm or less. The present inventors have succeeded in obtaining an Nd—Fe—B rare earth sintered magnet that significantly improves the magnetic properties of an Nd magnet alloy and whose coercive force does not deteriorate even when the carbon concentration exceeds 0.1 mass%.

Accordingly, the present invention provides the following Nd—Fe—B rare earth permanent sintered magnet material.
(I) R—Fe—Co—B—Al—Cu (where R is one or more of Nd, Pr, Dy, Tb, and Ho and contains 15 to 33% by mass of Nd) a permanent magnet material, an Nd-Fe-B based magnet alloy containing below 0.3 wt% exceeding 0.1 mass% of carbon, (i) M-B compound, M-B-Cu And at least two of M-C compounds and M-C compounds (M is one or more of Ti, Zr, and Hf), and (ii) R oxide is precipitated in the alloy structure, and Nd-Fe-B rare earths characterized in that the average particle size of the precipitated compounds is 5 μm or less, and the maximum distance between adjacent compounds deposited in the alloy structure is dispersed to 50 μm or less. Permanent sintered magnet material.
(II) The abundance ratio of the R ₂ Fe ₁₄ B ₁ phase as the main phase component is 89 to 99%, and the abundance ratio of the total of the rare earth or rare earth and transition metal borides, carbides and oxides is 0. The Nd—Fe—B rare earth permanent sintered magnet material according to (I), which is 1 to 3%.
(III) The Nd—Fe—B system according to (I) or (II), wherein the giant abnormally grown grains of the R ₂ Fe ₁₄ B ₁ phase having a grain size of 50 μm or more are 3% or less in the existing capacity ratio with respect to the entire metal structure Rare earth permanent sintered magnet material.
(IV) The magnetic characteristics are 12.5 kG or more in Br, the coercive force iHc is 10 kOe or more, and the squareness ratio 4 × (BH) max / Br ² is 0.95 or more (I), (II) or (III) The Nd-Fe-B rare earth permanent sintered magnet material described.
(V) Nd—Fe—B based magnet alloy in mass percentage, R27 to 33% (where R is one or more of Nd, Pr, Dy, Tb, Ho, and Nd is 15 to 33) %), Co 0.1 to 10%, B 0.8 to 1.5%, Al 0.05 to 1.0%, Cu 0.02 to 1.0%, Ti, Zr and Hf. Nd- according to any one of (I) to (IV), comprising 02 to 1.0%, O 0.04 to 0.4%, N 0.002 to 0.1%, and the balance Fe and inevitable impurities Fe-B rare earth permanent sintered magnet material.

  According to the Nd-Fe-B rare earth permanent magnet material of the present invention, two or more of the above-mentioned MB compound, MB-Cu compound, and MC compound and R oxide are finely precipitated. As a result, abnormal grain growth is suppressed, the optimum sintering temperature range is widened, and good magnetic properties are obtained even at high carbon and low oxygen concentrations.

The Nd—Fe—B rare earth permanent magnet material of the present invention is R—Fe—Co—B—Al—Cu (where R is one or more of Nd, Pr, Dy, Tb, and Ho). Is a rare earth permanent magnet material containing 15 to 33% by mass of Nd, preferably more than 0.1% by mass and 0.3% by mass or less, and more preferably more than 0.1% by mass of carbon. The abundance ratio of the Nd ₂ Fe ₁₄ B ₁ phase as the main phase component is 89-99%, and the abundance ratio of the rare earth or rare earth and transition metal borides, carbides and oxides. In an Nd-Fe-B magnet alloy of 0.1 to 3%, M is one or more of Ti, Zr, and Hf in the metal structure of the alloy, and an M-B compound, M- An alloy of at least two or more of B-Cu compounds and MC compounds, and further an R oxide Deposited in weaving, and the following average particle size 5μm of its deposit compounds, and the maximum spacing between compounds present adjacent in the alloy is characterized in that uniformly distributed in 50μm or less.

The magnetic characteristics of the Nd-Fe-B based magnet alloy include increasing the abundance ratio of the Nd ₂ Fe ₁₄ B ₁ phase that exhibits magnetism and reducing the nonmagnetic Nd-rich grain boundary phase in inverse proportion to it. Improvement of residual magnetic flux density and energy product has been attempted. The Nd-rich phase has a role of generating a coercive force by cleaning the crystal grain boundaries of the main phase Nd ₂ Fe ₁₄ B ₁ phase and removing impurities and crystal defects at the grain boundaries. Therefore, no matter how high the magnetic flux density is, the Nd-rich phase cannot be completely eliminated from the structure of the magnet alloy, and the grain boundary is cleaned as efficiently as possible using a small amount of the Nd-rich phase. Therefore, how to obtain a large coercive force is the main point in developing magnetic properties.

In general, since the Nd-rich phase is active, it is easily oxidized, carbonized or nitrided through pulverization or sintering processes, and Nd is consumed. If this happens, the grain boundary structure cannot be completely sounded and a predetermined coercive force cannot be obtained. In order to obtain a high-performance magnet with a high residual magnetic flux density and a large coercive force, in other words, to obtain magnetic properties by effectively using the minimum amount of Nd-rich phase, oxidation of the Nd-rich phase in the manufacturing process including raw materials is performed. Measures to prevent carbonization and nitriding are necessary.
In the sintering process, densification proceeds by a sintering reaction of fine powder. The molded fine powder diffuses while being bonded to each other at the sintering temperature, and fills the space in the sintered body by shrinking the interstitial pores to the outside and contracts. It is said that the Nd-rich liquid phase coexisting at this time smoothly promotes the sintering reaction.
However, if the carbon concentration of the sintered body is increased by using an inexpensive raw material with a high carbon concentration, a large amount of Nd carbide is generated, and it becomes impossible to clean crystal grain boundaries and remove impurities or crystal defects at the grain boundaries. It is considered that the coercive force is significantly reduced.

Therefore, the present inventor precipitated two or more of an M-B compound, an M-B-Cu compound, and an MC compound in a high carbon concentration Nd-Fe-B-based magnet alloy, The production of Nd carbide was remarkably suppressed, and B in the R ₂ Fe ₁₄ B ₁ phase, which is the main phase particle, was successfully replaced with C, and the effects of the present invention were obtained.
In addition, in a high-performance Nd magnet with a reduced Nd content and further suppressed oxidation in the process, the pinning effect cannot be sufficiently exhibited due to the insufficient amount of Nd oxide. For this reason, the phenomenon of generation of huge abnormally grown grains in which specific crystal grains grow rapidly and greatly at the sintering temperature appears, and it is considered that the squareness is remarkably lowered mainly.

With respect to the above problem, at least two of the MB compound, the MB-Cu compound, and the MC compound and further the R oxide are precipitated in the Nd magnet alloy, so that the grain boundaries thereof are precipitated. It is considered that the abnormal grain growth of the sintered body could be suppressed by the pinning effect at.
Due to the effects of such M-B compounds, M-B-Cu compounds, M-C compounds and further R oxides, it is possible to suppress the occurrence of giant abnormally grown grains in a wide sintering temperature range. Thus, the giant abnormally grown grains of the R ₂ Fe ₁₄ B ₁ phase having a grain size of 50 μm or more can be made 3% or less in terms of the existing capacity with respect to the entire metal structure.
Furthermore, due to the effects of the M-B compound, M-B-Cu compound, and M-C compound, the decrease in coercive force of the sintered body having a high carbon concentration can be remarkably suppressed, and even at a high carbon concentration, the high It became possible to manufacture characteristic magnets.

As described above, the rare earth permanent magnet material of the present invention preferably has an abundance ratio of Nd ₂ Fe ₁₄ B ₁ phase as a main phase component of 89 to 99%, more preferably 93 to 98%, and Further, in the high-characteristic Nd—Fe—B based magnet alloy in which the existing capacity ratio of the rare earth or rare earth and transition metal borides, carbides and oxides is 0.1 to 3%, more preferably 0.5 to 2%, In the metal structure of the alloy, at least two kinds of MB compound, MB-Cu compound, and MC compound, and further R oxide precipitates in the alloy structure, and the precipitation average particle size thereof As 5 μm or less, preferably 0.1 to 5 μm, particularly 0.5 to 2 μm, and the maximum distance between adjacent deposits in the alloy is 50 μm or less, preferably 5 to 10 μm, and uniformly dispersed. In this case, this rare earth permanent It is preferable that the giant abnormally grown grains of the R ₂ Fe ₁₄ B ₁ phase having a grain size of 50 μm or more in the magnet material is 3% or less in terms of the existing capacity with respect to the entire metal structure. The Nd-rich phase is preferably 0.5 to 10%, particularly 1 to 5%.

  Here, the composition of the rare earth permanent magnet alloy is R = 27 to 33%, particularly 28.8 to 31.5%, Co = 0.1 to 10%, particularly 1.3 to 3% by mass. .4%, B = 0.8 to 1.5%, preferably 0.9 to 1.4%, especially 0.95 to 1.15%, Al = 0.05 to 1.0%, especially 0. 1 to 0.5%, Cu = 0.02 to 1.0%, particularly 0.05 to 0.3%, an element selected from Ti, Zr and Hf = 0.02 to 1.0%, especially 0. 04 to 0.4%, C = over 0.1% to 0.3%, particularly over 0.1% to 0.2%, O = 0.04 to 0.4%, especially 0.06 to 0.3%, N = 0.002 to 0.1%, particularly 0.005 to 0.1%, Fe = remainder, and further preferably composed of inevitable impurities.

  Here, R indicates one or more of the rare earth elements, but Nd is an essential element, and Nd is contained in the alloy composition in an amount of 15 to 33% by mass, particularly 18 to 33% by mass. is required. In this case, as described above, R is contained in an amount of 27 to 33% by mass. However, if it is less than 27% by mass, iHc may be significantly reduced. If it exceeds 33% by mass, Br may be significantly reduced. 27-33 mass%.

  In the present invention, replacing part of Fe with Co is effective in improving the Curie temperature Tc. Co is also effective in reducing the mass of the sintered body when the magnet is exposed to high temperature and high humidity. However, if Co is less than 0.1% by mass, the effect of Tc improvement and mass reduction is small, and the cost is reduced. In consideration of this, the content is preferably 0.1 to 10% by mass.

  If B is less than 0.8% by mass, iHc may be significantly reduced. If it exceeds 1.5% by mass, Br may be significantly reduced. It is good.

  Al is effective in increasing the coercive force iHc without cost, but if it is less than 0.05% by mass, the effect of increasing iHc is very small, and if it exceeds 1.0% by mass, the decrease in Br is reduced. Since there exists a possibility that it may become large, it is good to set it as 0.05-1.0 mass%.

  If Cu is less than 0.02% by mass, the effect of increasing iHc is very small, and if it exceeds 1.0% by mass, the reduction of Br may increase, so 0.02 to 1.0% by mass. It is good.

  Elements selected from Ti, Zr, and Hf can widen the optimum sintering temperature region due to the combined effect of Cu and C, further create carbon and compounds, and prevent carbonization of the Nd-rich phase, especially in the magnetic properties It is effective in increasing iHc. If the amount is less than 0.02% by mass, the effect of increasing iHc is very small. If the amount exceeds 1.0% by mass, the reduction of Br may increase, so 0.02 to 1.0% by mass is preferable. .

  If the carbon (C) content is 0.1% by mass or less, particularly 0.05% by mass or less, the meaning of the present invention cannot be fully utilized, and if it exceeds 0.3% by mass, Since the effect cannot be exhibited, it is preferable to exceed 0.1% by mass and not more than 0.3% by mass, particularly more than 0.1% by mass and not more than 0.2% by mass.

If the nitrogen (N) content is less than 0.002% by mass, oversintering tends to occur and the squareness is not good, and if it exceeds 0.1% by mass, the sinterability and squareness are poor. Since there exists a possibility of reducing a coercive force, it is good to set it as 0.002-0.1 mass%.
The oxygen (O) content is preferably 0.04 to 0.4 mass%.

  The raw materials such as Nd, Pr, Dy, Tb, Cu, Ti, Zr, and Hf used in the present invention may be alloys or mixtures with Fe, Al, and the like. Further, a small amount of La, Ce, Sm, Ni, Mn, Si, Ca, Mg, S, P, W, Mo, Ta contained in the raw material used or mixed during the manufacturing process is 0.2% by mass or less. , Cr, Ga and Nb do not impair the effects of the present invention.

  The permanent magnet material of the present invention uses the necessary materials as shown in the examples to be described later, and after obtaining an alloy according to a conventional method, it is subjected to hydrogenation treatment and dehydrogenation treatment as necessary, pulverized, and molded , Sintering, and heat treatment, and a two-alloy method can also be employed.

  In this case, by using a raw material having a particularly high carbon concentration and selecting the addition amount of Ti, Zr, and Hf so as to be within these preferable existence ranges (0.02 to 1.0% by mass), 1,000 By sintering in an inert gas atmosphere at ˜1,200 ° C. for 0.5 to 5 hours, and further heat-treating in an inert gas atmosphere at 300 to 600 ° C. for 0.5 to 5 hours, A magnetic material can be obtained.

According to the present invention, R—Fe—Co—B—Al—Cu— based on the R—Fe—Co—B—Al—Cu system and containing a high concentration of carbon and a very small amount of Ti, Zr or Hf. Residual magnetic flux density (Br) and coercive force (iHc) are obtained by alloy casting, crushing, molding, sintering, and heat treatment at a temperature lower than the sintering temperature in a certain composition range of Ti, Zr or Hf. It is possible to provide a magnet alloy that is large, excellent in squareness, and has a wide optimum sintering temperature range.
Therefore, the permanent magnet material of the present invention has excellent magnetic properties such that the magnetic properties are 12.5 kG or more in Br, the coercive force iHc is 10 kOe or more, and the squareness ratio 4 × (BH) max / Br ² is 0.95 or more. It can have.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
In the rare earth permanent magnet materials of the following examples, the existing capacity ratio of the R ₂ Fe ₁₄ B ₁ phase, the existing capacity ratio of the rare earth or rare earth and transition metal borides, carbides and oxides, and the particle size of 50 μm or more. Table 13 summarizes the abundance ratio of the R ₂ Fe ₁₄ B ₁ phase giant abnormally grown grains.
In the following examples, the starting material having a high carbon concentration means that the total carbon concentration in the raw material is more than 0.1% by mass and up to 0.2% by mass, and sufficient magnetic properties can be obtained with the conventional technology. It is a raw material that can not be. In addition, starting materials not specifically described have a total carbon concentration of 0.005 to 0.05 mass%.

[Example 1]
As starting materials, Nd, Pr, electrolytic iron, Co, ferroboron, Al, Cu and titanium were used, and the mass ratio was 28.9Nd-2.5Pr-BAL. After blending with the composition of Fe-4.5Co-1.2B-0.7Al-0.4Cu-XTi (X = 0, 0.04, 0.4, 1.4), an alloy is obtained by a single roll quenching method. It was. The obtained alloy was hydrogenated in a hydrogen atmosphere of + 1.5 ± 0.3 kgf / cm ² , and dehydrogenated at 800 ° C. for 3 hours in a vacuum of 10 ⁻² Torr or less. The alloy obtained at this time has become a coarse powder of several hundred μm by hydrogenation / dehydrogenation treatment. The obtained coarse powder and 0.1% by mass of stearic acid as a lubricant were mixed with a V mixer, and further pulverized to an average particle size of about 3 μm with a jet mill in a nitrogen stream. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 25 kOe, and molded at a pressure of 0.5 ton / cm ^{2 in} a direction perpendicular to the magnetic field. Sintered in an Ar atmosphere every 10 ° C up to 1,200 ° C for 2 hours, further cooled, and then heat treated in an Ar atmosphere at 500 ° C for 1 hour to obtain permanent magnet materials of each composition It was. Note that the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials are C = 0.111 to 0.133 mass% and O = 0.095, respectively. It was -0.116 mass% and N = 0.079-0.097 mass%.

Table 1 shows the results of the obtained magnetic characteristics. The 0.04% and 0.4% Ti-added products are good at 1040 to 1,070 ° C with almost no change in Br, iHc and squareness ratio, and the optimum sintering temperature range is 30 ° C. Recognize.
It can be seen that the 0% Ti-added product has low iHc and poor squareness when the carbon concentration is 0.111 to 0.133% by mass as in this example. The 1.4% Ti-added product is good at 1040 to 1,070 ° C. with almost no change in Br, iHc, squareness ratio, and the optimum sintering temperature range is 30 ° C., but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values than the products containing 0.04% and 0.4% Ti.

[Example 2]
As a starting material, Nd, Dy, electrolytic iron, Co, ferroboron, Al, Cu, and titanium having a high carbon concentration were used. As a study of the amount of Ti added, 28.6 Nd-2.5 Dy-BAL. After blending into the composition of Fe-9.0Co-1.0B-0.8Al-0.6Cu-XTi (X = 0.01, 0.2, 0.6, 1.5), high-frequency dissolution, water-cooled copper An ingot of each composition was obtained by casting into a mold. These ingots were coarsely pulverized with a brown mill, and the obtained coarse powder and 0.05% by mass of lauric acid as a lubricant were mixed with a V mixer, and further treated with a jet mill in a nitrogen stream to obtain an average particle size. A fine powder of about 5 μm was obtained. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 15 kOe, and molded at a pressure of 1.2 ton / cm ^{2 in} a direction perpendicular to the magnetic field. , Sintered at 200 ° C. for 2 hours in a vacuum atmosphere of 10 ⁻⁴ Torr or less, further cooled, and then heat treated at 500 ° C. for 1 hour in a vacuum atmosphere of 10 ⁻² Torr or less to obtain a permanent composition. A magnet material was obtained. Note that the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials are C = 0.180 to 0.208 mass% and O = 0.328, respectively. It was -0.398 mass% and N = 0.027-0.041 mass%.

The obtained magnetic property results are shown in Table 2. The 0.2% and 0.6% Ti-added products are good at 1,100 to 1,130 ° C with almost no change in Br, iHc, and squareness ratio, and the optimum sintering temperature range is 30 ° C. Recognize.
It can be seen that the 0.01% Ti-added product has a low iHc and poor squareness when the carbon concentration is 0.180 to 0.208% by mass as in this example.
The 1.5% Ti-added product is good at 1,100 to 1,130 ° C with almost no change in Br, iHc, squareness ratio, and the optimum sintering temperature range is 30 ° C, but the amount added is too much Therefore, it can be seen that both Br and iHc have lower values than the products with 0.2% and 0.6% Ti added.

[Example 3]
As a starting material, Nd, Tb, electrolytic iron, Co, ferroboron, Al, Cu and titanium having a high carbon concentration were used, and a two-alloy method was used, and the mother alloy was 27.3 Nd-BAL. In the composition of Fe-0.5Co-1.0B-0.4Al-0.2Cu, the auxiliary alloy is 46.2 Nd-17.0 Tb-BAL. The composition was Fe-18.9Co-XTi (X = 0.2, 4.0, 9.8, 25). The composition after mixing was 29.2Nd-1.7Tb-BAL. Fe-2.3Co-0.9B-0.4Al-0.2Cu-XTi (X = 0.01, 0.2, 0.5, 1.3). The mother alloy is produced by a single roll quenching method, subjected to hydrogenation treatment in a hydrogen atmosphere of +0.5 to +2.0 kgf / cm ² , and semi-dehydrogenated at 500 ° C. for 3 hours in a vacuum of 10 ⁻² Torr or less. Processed. The auxiliary alloy was melted at high frequency and cast into a water-cooled copper mold to obtain an ingot.

Next, 90% by mass of the master alloy and 10% by mass of the auxiliary material are weighed, 0.05% by mass of PVA is added as a lubricant, mixed with a V mixer, and further, an average particle diameter of 4 μm is obtained by a jet mill in a nitrogen stream. About a fine powder was obtained. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 15 kOe, and molded at a pressure of 0.5 ton / cm ^{2 in} a direction perpendicular to the magnetic field. Sintered every 10 ° C to 1,200 ° C for 2 hours in a vacuum atmosphere of 10 ^-4 Torr or less, further cooled, and then heat treated at 500 ° C for 1 hour in an Ar gas atmosphere of 10 ^-2 Torr or less. The permanent magnet material of each composition was obtained. In addition, the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials are C = 0.248 to 0.268 mass% and O = 0.225, respectively. It was -0.298 mass%, N = 0.029-0.040 mass%.

Table 3 shows the magnetic characteristics obtained. The 0.2% and 0.5% Ti-added products are good at 1,060 to 1,090 ° C with almost no change in Br, iHc and squareness ratio, and the optimum sintering temperature range is 30 ° C. Recognize.
It can be seen that the 0.01% Ti-added product has a low iHc and poor squareness when the carbon concentration is 0.248 to 0.268% by mass as in this example. The 1.3% Ti-added product is good at 1,060 to 1,090 ° C. with almost no change in Br, iHc and squareness ratio, and the optimum sintering temperature range is 30 ° C., but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values than the products with 0.2% and 0.5% Ti added.

[Example 4]
As a starting material, Nd, Pr, Dy, electrolytic iron, Co, ferroboron, Al, Cu and titanium having a high carbon concentration were used, and a two-alloy method was used as in the previous example. The mother alloy was 26.8 Nd-2.2 Pr-BAL. In the composition of Fe-0.5Co-1.0B-0.2Al, the auxiliary alloy is 37.4Nd-10.5Dy-BAL. The composition was Fe-26.0Co-0.8B-0.2Al-1.6Cu-XTi (X = 0, 1.2, 7.0, 17.0). The composition after mixing was 27.9 Nd-2.0 Pr-1.1 Dy-BAL. Fe-3.0Co-1.0B-0.2Al-0.2Cu-XTi (X = 0, 0.1, 0.7, 1.7). Both the mother alloy and the auxiliary alloy were produced by a single roll quenching method. Only the mother alloy is subjected to hydrogenation treatment in a hydrogen atmosphere of +0.5 to +2.0 kgf / cm ² , and subjected to a semi-dehydrogenation treatment at 500 ° C. for 3 hours in a vacuum of 10 ⁻² Torr or less. A coarse powder of several hundred μm was obtained. The auxiliary alloy was pulverized with a brown mill to obtain a coarse powder having an average particle size of several hundreds of μm.

Next, 90% by mass of the master alloy and 10% by mass of the auxiliary material are weighed, 0.1% by mass of caproic acid is added as a lubricant, mixed by a V mixer, and further average particle size is obtained by a jet mill in a nitrogen stream. A fine powder of about 5 μm was obtained. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 20 kOe, and molded at a pressure of 0.8 ton / cm ^{2 in} a direction perpendicular to the magnetic field. Sintered every 10 ° C to 1,200 ° C for 2 hours in a vacuum atmosphere of 10 ^-4 Torr or less, further cooled, and then heat treated at 500 ° C for 1 hour in an Ar gas atmosphere of 10 ^-2 Torr or less. The permanent magnet material of each composition was obtained. Note that the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials are C = 0.198 to 0.222 mass% and O = 0.095, respectively. It was -0.138 mass%, N = 0.069-0.090 mass%.

Table 4 shows the obtained magnetic characteristics. The 0.1% and 0.7% Ti-added products are good at 1,070 to 1,100 ° C. with almost no change in Br, iHc and squareness, and the optimum sintering temperature range is 30 ° C. Recognize.
It can be seen that the product without Ti addition has a low iHc and poor squareness when the carbon concentration is 0.198 to 0.222% by mass as in this example. The 1.7% Ti-added product is good at 1,070 to 1,100 ° C. with almost no change in Br, iHc, and squareness ratio, and has an optimum sintering temperature range of 30 ° C., but the added amount is too large. Therefore, it can be seen that both Br and iHc have lower values than the products with 0.1% and 0.7% Ti added.

When the element distribution image by EPMA (Electron Probe Micro Analysis) is observed for each sample of Examples 1 to 4, the Ti amount is 0.02 to 1.0% by mass in the preferred range of the present invention. The TiB compound, TiBCu compound, and TiC compound having a diameter of 5 μm or less were uniformly and finely deposited at intervals of 50 μm or less.
From these, an appropriate amount of Ti is added, and TiB compound, TiBCu compound and TiC compound are uniformly and finely precipitated in the sintered body, thereby suppressing abnormal grain growth and widening the optimum sintering temperature range, It can be seen that good magnetic properties are obtained even at such high carbon and low oxygen concentrations.

[Example 5]
As a starting material, Nd, Pr, Dy, Tb, electrolytic iron, Co, ferroboron, Al, Cu, and zirconium having a high carbon concentration were used, and as a comparison of the amount of Zr added, 26.7 Nd-1.1 Pr- 1.3 Dy-1.2 Tb-BAL. After blending with the composition of Fe-3.6Co-1.1B-0.4Al-0.1Cu-XZr (X = 0, 0.1, 0.6, 1.3), an alloy is obtained by a twin roll quenching method. It was. The obtained alloy was hydrogenated in a hydrogen atmosphere of + 1.0 ± 0.2 kgf / cm ² and dehydrogenated at 700 ° C. for 5 hours in a vacuum of 10 ⁻² Torr or less. The alloy obtained at this time has become a coarse powder of several hundred μm by hydrogenation / dehydrogenation treatment. The obtained coarse powder and 0.1% by mass of panacet as a lubricant were mixed with a V mixer, and further pulverized to an average particle size of about 5 μm with a jet mill in a nitrogen stream. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 20 kOe, and molded in a direction perpendicular to the magnetic field at a pressure of 1.2 ton / cm ^2. Sintered at 200 ° C. for 2 hours in an Ar atmosphere, further cooled, and then heat treated at 500 ° C. for 1 hour in an Ar atmosphere to obtain permanent magnet materials of the respective compositions. Note that the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B based permanent magnet materials are C = 0.141 to 0.153 mass% and O = 0.093, respectively. It was -0.108 mass% and N = 0.059-0.074 mass%.

Table 5 shows the results of the obtained magnetic characteristics. The 0.1% and 0.6% Zr-added products are good at 1,050 to 1,080 ° C. with almost no change in Br, iHc and squareness, and the optimum sintering temperature range is 30 ° C. Recognize.
It can be seen that the Zr-free product has an extremely low iHc value when the carbon concentration is 0.141 to 0.153 mass% as in this example. The 1.3% Zr-added product is good at 1,050 to 1,080 ° C. with almost no change in Br, iHc, squareness ratio, and the optimum sintering temperature range is 30 ° C., but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values.

[Example 6]
As a starting material, Nd, Dy, electrolytic iron, Co, ferroboron, Al, Cu, and ferrozirconium having a large carbon concentration were used, and as a comparison of the presence or absence of Zr addition, 28.7 Nd-2.5 Dy-BAL. After blending into the composition of Fe-1.8Co-1.0B-0.8Al-0.2Cu-XZr (X = 0.01, 0.07, 0.7, 1.4), it was melted at high frequency, and water-cooled copper An ingot of each composition was obtained by casting into a mold. These ingots were coarsely pulverized with a brown mill, and the obtained coarse powder and 0.07% by mass of orphine as a lubricant were mixed with a V mixer, and further treated with a jet mill in a nitrogen stream to obtain an average particle size of 5 μm. About a fine powder was obtained. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 20 kOe, and molded at a pressure of 0.7 ton / cm ^{2 in} a direction perpendicular to the magnetic field. Sintered at 200 ° C. for 2 hours in an Ar atmosphere, further cooled, and then heat treated at 500 ° C. for 1 hour in an Ar atmosphere to obtain permanent magnet materials of the respective compositions. Note that the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials are C = 0.141 to 0.162 mass% and O = 0.248, respectively. It was -0.271 mass% and N = 0.003-0.010 mass%.

Table 6 shows the results of the obtained magnetic characteristics. 0.07% and 0.7% Zr-added products are good at 1,110 to 1,140 ° C. with almost no change in Br, iHc and squareness ratio, and have an optimum sintering temperature range of 30 ° C. Recognize.
It can be seen that the 0.01% Zr-added product has a high carbon concentration as in this example, and iHc has an extremely low value when the oxygen concentration is low. The 1.4% Zr-added product is good with almost no change in Br, iHc, squareness ratio at 1,110 to 1,140 ° C, and the optimum sintering temperature range is 30 ° C, but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values.

[Example 7]
An attempt was made to further improve the characteristics of the present invention by utilizing a two-alloy method. As starting materials, Nd, Dy, electrolytic iron, Co, ferroboron, Al, Cu, and zirconium having a high carbon concentration were used, and the master alloy was 28.3 Nd-BAL. The composition of Fe-0.9Co-1.2B-0.2Al-XZr (X = 0, 0.07, 0.7, 1.4) was added to the auxiliary alloy in a mass ratio of 34.0 Nd-19.2 Dy. -BAL. The composition was Fe-24.3Co-0.2B-1.5Cu. The composition after mixing was 28.9Nd-1.9Dy-BAL. Fe-3.3Co-1.1B-0.2Al-0.2Cu-XZr (X = 0, 0.06, 0.6, 1.3). The mother alloy is produced by a single roll quenching method, subjected to hydrogenation treatment in a hydrogen atmosphere of +0.5 to +2.0 kgf / cm ² , and semi-dehydrogenated at 500 ° C. for 3 hours in a vacuum of 10 ⁻² Torr or less. Processed. The auxiliary alloy was melted at high frequency and cast into a water-cooled copper mold to obtain an ingot.

Next, 90% by mass of the master alloy and 10% by mass of the auxiliary material were weighed, 0.05% by mass of stearic acid was added as a lubricant, mixed with a V mixer, and further average particle size was measured with a jet mill in a nitrogen stream. A fine powder of about 4 μm was obtained. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 15 kOe, and molded at a pressure of 0.5 ton / cm ^{2 in} a direction perpendicular to the magnetic field. Sintered every 10 ° C to 1,200 ° C for 2 hours in a vacuum atmosphere of 10 ^-4 Torr or less, further cooled, and then heat treated at 500 ° C for 1 hour in an Ar gas atmosphere of 10 ^-2 Torr or less. The permanent magnet material of each composition was obtained. Note that the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials were C = 0.203 to 0.217 mass%, and O = 0.125, respectively. It was -0.158 mass% and N = 0.021-0.038 mass%.

Table 7 shows the obtained magnetic property results. The 0.06% and 0.6% Zr-added products are good at 1,060 to 1,090 ° C with almost no change in Br, iHc and squareness, and the optimum sintering temperature range is 30 ° C. Recognize.
It can be seen that the Zr-free product has an extremely low iHc value when the carbon concentration is 0.203 to 0.217% by mass as in this example. The 1.3% Zr-added product is good at 1,060 to 1,090 ° C. with almost no change in Br, iHc, squareness ratio, and the optimum sintering temperature range is 30 ° C., but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values than the 0.06% and 0.6% Zr-added products.

[Example 8]
As a starting material, Nd, Dy, electrolytic iron, Co, ferroboron, Al, Cu and zirconium were used, and the two-alloy method was used as in the previous examples. The mother alloy was 27.0 Nd-1.3 Dy-BAL. The composition of Fe-1.8Co-1.0B-0.2Al-0.1Cu was mixed with the auxiliary alloy in a mass ratio of 25.1 Nd-28.3 Dy-BAL. The composition was Fe-23.9Co-XZr (X = 0.1, 1.0, 5.0, 11.0). The composition after mixing was 26.8 Nd-4.0 Dy-BAL. Fe-4.0Co-0.9B-0.2Al-0.1Cu-XZr (X = 0.01, 0.1, 0.5, 1.1). Both the mother alloy and the auxiliary alloy are produced by a single roll quenching method, subjected to hydrogenation treatment in a hydrogen atmosphere of +0.5 to +1.0 kgf / cm ² , and 500 ° C. × 4 hours in a vacuum of 10 ⁻² Torr or less. Semi-dehydrogenation treatment was performed to obtain a coarse powder having an average particle size of several hundreds of μm.

Next, 90% by mass of the master alloy and 10% by mass of the auxiliary material are weighed, 0.15% by mass of lauric acid is added as a lubricant, mixed with a V mixer, and further averaged by a jet mill in a nitrogen stream. A fine powder of about 5 μm was obtained. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 16 kOe, and molded at a pressure of 0.6 ton / cm ^{2 in} a direction perpendicular to the magnetic field. Sintered every 10 ° C for up to 1,200 ° C for 2 hours in a vacuum atmosphere of 10 ^-4 Torr or less, further cooled, and then heat treated in an Ar gas atmosphere for 1 hour at 500 ° C. A magnet material was obtained. The carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials are C = 0.101 to 0.132 mass% and O = 0.065, respectively. It was -0.110 mass% and N = 0.015-0.028 mass%.

Table 8 shows the results of the obtained magnetic characteristics. The 0.1% and 0.5% Zr-added products are good at 1,070 to 1,100 ° C. with almost no change in Br, iHc and squareness, and the optimum sintering temperature range is 30 ° C. Recognize.
The 0.01% Zr-added product has a good ratio of Br, iHc, and squareness when sintered at 1,070 ° C., but the optimum sintering temperature range is 0.1% and 0.5% Zr-added product. You can see that it is narrow. The 1.1% Zr-added product is good at 1,070 to 1,100 ° C. with almost no change in Br, iHc, squareness ratio, and the optimum sintering temperature range is 30 ° C., but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values than the products containing 0.1% and 0.5% Zr.

When the element distribution image by EPMA is seen about each sample of these Examples 5-8, in a sintered compact whose Zr amount is 0.02-1.0 mass% which is the suitable range of this invention, a diameter is 5 micrometers. The following ZrB compound, ZrBCu compound and ZrC compound were uniformly and finely precipitated at intervals of 50 μm or less.
From these, an appropriate amount of Zr is added, and the ZrB compound, ZrBCu compound and ZrC compound are uniformly and finely precipitated in the sintered body, thereby suppressing abnormal grain growth and expanding the optimum sintering temperature range, It can be seen that good magnetic properties are obtained even at such high carbon and low oxygen concentrations.

[Example 9]
As starting materials, Nd, Pr, Dy, electrolytic iron, Co, ferroboron, Al, Cu and hafnium were used, and the mass ratio was 26.7Nd-2.2Pr-2.5Dy-BAL. After blending with the composition of Fe-2.7Co-1.2B-0.4Al-0.3Cu-XHf (X = 0, 0.2, 0.5, 1.4), an alloy is obtained by a single roll quenching method. It was. The obtained alloy was hydrogenated in a hydrogen atmosphere of + 1.0 ± 0.3 kgf / cm ² and dehydrogenated at 400 ° C. for 5 hours in a vacuum of 10 ⁻² Torr or less. The alloy obtained at this time has become a coarse powder of several hundred μm by hydrogenation / dehydrogenation treatment. The obtained coarse powder and 0.1% by mass of caproic acid as a lubricant were mixed with a V mixer, and further pulverized to an average particle size of about 6 μm with a jet mill in a nitrogen stream. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 20 kOe, and molded at a pressure of 1.5 ton / cm ^{2 in} a direction perpendicular to the magnetic field. Sintered at 200 ° C. for 2 hours in an Ar atmosphere, further cooled, and then heat treated at 500 ° C. for 1 hour in an Ar atmosphere to obtain permanent magnet materials of the respective compositions. Note that the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials are C = 0.111 to 0.123 mass% and O = 0.195, respectively. It was -0.251 mass% and N = 0.0009-0.017 mass%.

Table 9 shows the results of the obtained magnetic characteristics. The 0.2% and 0.5% Hf-added products are good at 1020 to 1,050 ° C. with almost no change in Br, iHc and squareness, and the optimum sintering temperature range is 30 ° C. Recognize.
It can be seen that the 0% Hf-added product has a low iHc and poor squareness when the carbon concentration is 0.111 to 0.123 mass% as in this example. The 1.4% Hf-added product is good at 1,020 to 1,050 ° C. with almost no change in Br, iHc and squareness ratio, and the optimum sintering temperature range is 30 ° C., but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values than the products containing 0.2% and 0.5% Hf.

[Example 10]
As a starting material, Nd, electrolytic iron, Co, ferroboron, Al, Cu, and hafnium having a high carbon concentration were used. As a study of the amount of Hf added, 31.1Nd-BAL. After blending into a composition of Fe-3.6Co-1.1B-0.6Al-0.3Cu-XHf (X = 0.01, 0.4, 0.8, 1.5), high-frequency dissolution, water-cooled copper An ingot of each composition was obtained by casting into a mold. These ingots were coarsely pulverized with a brown mill, and the obtained coarse powder and 0.05% by mass of oleic acid as a lubricant were mixed with a V mixer, and further treated with a jet mill in a nitrogen stream to obtain an average particle size. A fine powder of about 5 μm was obtained. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 12 kOe, and molded at a pressure of 0.3 ton / cm ^{2 in} a direction perpendicular to the magnetic field. , Sintered at 200 ° C. for 2 hours in a vacuum atmosphere of 10 ⁻⁴ Torr or less, further cooled, and then heat treated at 500 ° C. for 1 hour in a vacuum atmosphere of 10 ⁻² Torr or less to obtain a permanent composition. A magnet material was obtained. Note that the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials are C = 0.180 to 0.188 mass% and O = 0.068, respectively. It was -0.088 mass% and N = 0.062-0.076 mass%.

Table 10 shows the results of the obtained magnetic characteristics. The 0.4% and 0.8% Hf-added products are good at 1,050 to 1,080 ° C. with almost no change in Br, iHc and squareness, and the optimum sintering temperature range is 30 ° C. Recognize.
The 0.01% Hf-added product has a good ratio of Br, iHc, and squareness when sintered at 1,050 ° C., but the optimum sintering temperature range is higher than that of 0.4% and 0.8% Hf-added products. You can see that it is narrow. The 1.5% Hf-added product is good at 1,050 to 1,080 ° C. with almost no change in Br, iHc, squareness ratio, and the optimum sintering temperature range is 30 ° C., but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values than the products containing 0.4% and 0.8% Hf.

[Example 11]
An attempt was made to further improve the characteristics of the present invention by utilizing a two-alloy method. As a starting material, Nd, Dy, electrolytic iron, Co, ferroboron, Al, Cu, and hafnium having a high carbon concentration are used, and the mother alloy is 27.4 Nd-BAL. The composition of Fe-0.3Co-1.1B-0.4Al-0.2Cu was mixed with an auxiliary alloy in a mass ratio of 33.8 Nd-19.0 Dy-BAL. The composition was Fe-24.1Co-XHf (X = 0.1, 2.1, 7.9, 15). The composition after mixing was 28.0 Nd-1.9 Dy-BAL. Fe-2.7Co-1.0B-0.4Al-0.2Cu-XHf (X = 0.01, 0.2, 0.8, 1.5). The mother alloy is prepared by a single roll quenching method, hydrogenated in a hydrogen atmosphere of +0.5 to +2.0 kgf / cm ² , and half-dehydrogenated at 600 ° C. for 3 hours in a vacuum of 10 ⁻² Torr or less. Processed. The auxiliary alloy was melted at high frequency and cast into a water-cooled copper mold to obtain an ingot.

Next, 90% by mass of the master alloy and 10% by mass of the auxiliary material were weighed, 0.05% by mass of butyl laurate was added as a lubricant, mixed with a V mixer, and further averaged with a jet mill in a nitrogen stream. A fine powder having a diameter of about 5 μm was obtained. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 15 kOe, and molded at a pressure of 0.3 ton / cm ^{2 in} a direction perpendicular to the magnetic field. Sintered every 10 ° C to 1,200 ° C for 2 hours in a vacuum atmosphere of 10 ^-4 Torr or less, further cooled, and then heat treated at 500 ° C for 1 hour in an Ar gas atmosphere of 10 ^-2 Torr or less. The permanent magnet material of each composition was obtained. Note that the carbon (C), oxygen (O), and nitrogen (N) contents in these R—Fe—B permanent magnet materials were C = 0.283 to 0.297 mass% and O = 0.095, respectively. It was -0.108 mass% and N = 0.025-0.044 mass%.

Table 11 shows the obtained magnetic property results. The 0.2% and 0.8% Hf-added products are good at 1,120-1150 ° C. with almost no change in Br, iHc, squareness ratio, and the optimum sintering temperature range is 30 ° C. Recognize.
The 0.01% Hf-added product has a good ratio of Br, iHc, and squareness when sintered at 1,120 ° C, but the optimum sintering temperature range is higher than that of 0.2% and 0.8% Hf-added products. You can see that it is narrow. The 1.5% Hf-added product is good at 1,120-1150 ° C. with almost no change in Br, iHc, squareness ratio, and the optimum sintering temperature range is 30 ° C., but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values than the products containing 0.2% and 0.8% Hf.

[Example 12]
Nd, Dy, Tb, electrolytic iron, Co, ferroboron, Al, Cu, and hafnium were used as starting materials, and a two-alloy method was used as in the previous examples. The mother alloy was 26.0 Nd-2.5 Dy-BAL. The composition of Fe-1.4Co-1.0B-0.8Al-0.2Cu-XHf (X = 0, 0.06, 0.6, 1.7) was added to the auxiliary alloy in a mass ratio of 40.8 Nd. -18.0 Tb-BAL. The composition was Fe-20.0Co-0.1B-0.3Al. The composition after mixing was 27.5Nd-2.3Dy-1.8Tb-BAL. Fe-3.2Co-0.9B-0.8Al-0.2Cu-XHf (X = 0, 0.05, 0.5, 1.5). Both the mother alloy and the auxiliary alloy are produced by a single roll quenching method, subjected to hydrogenation treatment in a hydrogen atmosphere of +0.5 to +1.0 kgf / cm ² , and heated at 500 ° C. for 2 hours in a vacuum of 10 ⁻² Torr or less. Semi-dehydrogenation treatment was performed to obtain a coarse powder having an average particle size of several hundreds of μm.

Next, 90% by mass of the master alloy and 10% by mass of the auxiliary material are weighed, 0.1% by mass of caprylic acid is added as a lubricant, mixed with a V mixer, and further averaged by a jet mill in a nitrogen stream. A fine powder of about 5 μm was obtained. Thereafter, these fine powders are filled in a mold of a molding apparatus, oriented in a magnetic field of 25 kOe, and molded at a pressure of 0.5 ton / cm ^{2 in} a direction perpendicular to the magnetic field. Sintered every 10 ° C for up to 1,200 ° C for 2 hours in a vacuum atmosphere of 10 ^-4 Torr or less, further cooled, and then heat treated in an Ar gas atmosphere for 1 hour at 500 ° C. A magnet material was obtained. In addition, carbon (C), oxygen (O), and nitrogen (N) content in these R—Fe—B based permanent magnet materials are C = 0.102 to 0.128 mass%, O = 0.105, respectively. It was -0.148 mass%, N = 0.025-0.032 mass%.

Table 12 shows the obtained magnetic characteristics. 0.05% and 0.5% Hf-added products are good at 1,160 to 1,190 ° C. with little change in Br, iHc, squareness ratio, and optimum sintering temperature range is 30 ° C. Recognize.
The 0% Hf-added product has a good Br, iHc and squareness ratio at 1,160 ° C sintering, but the optimum sintering temperature range is narrower than the 0.05% and 0.5% Hf-added products. I understand. The 1.5% Hf-added product is good at 1,160 to 1,190 ° C. with almost no change in Br, iHc, squareness ratio, and the optimum sintering temperature range is 30 ° C., but the added amount is too large Therefore, it can be seen that both Br and iHc have lower values than the products containing 0.05% and 0.5% Hf.

When the element distribution image by EPMA is seen about each sample of these Examples 9-12, in a sintered compact whose Hf amount is 0.02-1.0 mass% which is the suitable range of this invention, a diameter is 5 micrometers. The following HfB compound, HfBCu compound and HfC compound were uniformly and finely precipitated at intervals of 50 μm or less.
From these, an appropriate amount of Hf is added, and the HfB compound, HfBCu compound, and HfC compound are uniformly and finely precipitated in the sintered body, thereby suppressing abnormal grain growth and widening the optimum sintering temperature range, It can be seen that good magnetic properties are obtained even at such high carbon and low oxygen concentrations.

Claims (5)

R—Fe—Co—B—Al—Cu (where R is one or more of Nd, Pr, Dy, Tb, and Ho and contains 15 to 33% by mass of Nd) based rare earth permanent magnet material , and the a Nd-Fe-B based magnet alloy containing below 0.3 wt% exceeding 0.1 mass% of carbon, M-B compound, M-B-Cu-based compound, M-C At least two of the system compounds (M is one or more of Ti, Zr, and Hf) and further an R oxide precipitates in the alloy structure, and the average particle size of the precipitated compound is 5 μm or less. The Nd—Fe—B rare earth permanent sintered magnet material is characterized in that the maximum distance between adjacently precipitated compounds in the alloy structure is dispersed to 50 μm or less. The existing capacity ratio of the main phase component R ₂ Fe ₁₄ B ₁ phase is 89 to 99%, and the total existing capacity ratio of rare earth or rare earth and transition metal borides, carbides and oxides is 0.1 to 3%. The Nd—Fe—B rare earth permanent sintered magnet material according to claim 1, wherein The Nd-Fe-B rare earth permanent sintered magnet according to claim 1 or 2, wherein the giant abnormally grown grains of the R ₂ Fe ₁₄ B ₁ phase having a particle size of 50 µm or more are 3% or less in the existing capacity ratio with respect to the entire metal structure. material. 4. The Nd—Fe—B according to claim 1, wherein the magnetic properties are 12.5 kG or more in Br, the coercive force iHc is 10 kOe or more, and the squareness ratio 4 × (BH) max / Br ² is 0.95 or more. system rare earth permanent sintered magnet material. The Nd—Fe—B based magnet alloy has a mass percentage of R27 to 33% (provided that R is one or more of Nd, Pr, Dy, Tb, and Ho and contains 15 to 33% of Nd. ), Co 0.1 to 10%, B 0.8 to 1.5%, Al 0.05 to 1.0%, Cu 0.02 to 1.0%, element 0.02 to 1 selected from Ti, Zr and Hf The Nd—Fe—B rare earth according to claim 1, comprising 0.0%, O 0.04 to 0.4%, N 0.002 to 0.1%, and the balance Fe and inevitable impurities. Permanent sintered magnet material.