JPH0551656B2 - - Google Patents

Description

[Detailed description of the invention]

[Object of the Invention] (Industrial Application Field) The present invention relates to a rare earth iron-based permanent magnet alloy with excellent magnetic properties. (Prior art) Intermetallic compounds consisting of rare earth metals (R) and iron (Fe) have large magnetocrystalline anisotropy and high saturation magnetization, and are promising as permanent magnet alloys with high coercive force and high energy product. Moreover, compared to conventional rare earth cobalt magnets, it has the advantage that the raw materials are cheaper. However, conventional rare-earth iron-based binary permanent magnet alloys can be formed into a bulk shape by normal melting, pulverization, and sintering, or when the alloy is pulverized for resin molding, even after optimal heat treatment. However, only a low coercive force was obtained, which was insufficient for use as a practical permanent magnet. (Problems to be Solved by the Invention) As a result of conducting various studies in view of the above points, the present invention has been developed to form a bulk material by a sintering method that is easy to process into any shape, or to crush an alloy and mold it into a resin. The object of the present invention is to provide a rare earth iron-based permanent magnet alloy that has high magnetic flux density, high coercive force, and maintains a high energy product even in such cases. [Structure of the invention] (Means for solving the problem) The present invention is based on the general formula R _1- 〓 _- 〓X〓Fe〓 [where R is Y, Ce, Pr, Nd, Sm, M, M (Mitshu Metal) one or more of the following, X is C,
One or more types of N, O, P, H, Al, Si]
, the range of α and β is 0.001≦ in terms of atomic ratio, respectively.
It is characterized by being defined by α≦0.5, 0.5≦β≦0.95, and α+β<1.0. Examples of the third element X added to the R-Fe binary system include C, N, O, P, H, S, Al, and Si. By adding these third elements X, stable rhombohedral, hexagonal, and
In addition to obtaining a crystal structure such as a tetragonal system, the coercive force is improved by imparting magnetic anisotropy along the C axis of the crystal. As X, especially N, C
is effective, but if necessary, B may be added to X in an atomic ratio of 0.001 to 0.09. This composite addition can improve the squareness of the 4πM-H curve. The amount of B added is
When B is less than 0.001, no improvement in squareness is observed, whereas when B exceeds 0.09, the magnetic flux density decreases and the maximum energy product becomes small. The atomic ratio of the added amount α of the third element X is 0.001
If α is less than 0.5, no increase in coercive force is observed and it is not practical as a permanent magnet alloy, and α is 0.5.
If a large amount of X is added exceeding the above range, the magnetic flux density will decrease, so the amount α of X added is defined within the above range. A more preferable amount of X to be added is in the range of 0.04≦α≦0.20. The Fe has an effective effect in improving the magnetic flux density in the magnet alloy of the present invention, and if the added amount β is less than 0.5, a sufficient ternary crystal structure cannot be obtained and the magnetic flux density also decreases. . In addition, the Fe
If the addition amount β exceeds 0.95 and the addition amount of Fe increases, the coercive force will decrease, so it is necessary to define it within the above range. More preferably, the amount of Fe added is 0.6
The range is ≦β≦0.86. The rare earth elements R include Y, Ce, Pr,
These include Nd, Sm, M, M, etc. These are essential elements to improve coercive force, and if the amount added is small, the coercive force decreases extremely, so 0.08
A range of ~0.30 is preferred. In addition, Gd is included in a part of R.
There is no problem in using heavy rare earth elements such as. After melting and pulverizing the alloy having the above composition, compacting the alloy,
After the obtained green compact is sintered, it is heat-treated to form a permanent magnet. Further, by bonding the alloy powder having the above composition with a resin, it can be used as a bonded magnet. The coercive force of the alloy powder can be improved by subjecting it to heat treatment before mixing it with the resin. Also,
Following the above heat treatment, the alloy powder is heat treated in an N ₂ atmosphere or an H ₂ atmosphere.
It is possible to contain N ₂ and H ₂ or to increase the content of N and H. Note that the alloy powder may be produced by a solid phase reaction such as mechanical alloying or a liquid quenching method. The obtained alloy powder is mixed with resin and molded into a bonded magnet. Furthermore, the alloy powder can be made into a bulk magnet by hot pressing or hot plastic working. (Function) According to the present invention, a bulk material is formed by a normal sintering method by adding a third element to a rare earth iron-based R-Fe binary system to form a ternary alloy. Also, by pulverizing the alloy and condensing the resin, it is possible to obtain a rare earth iron-based permanent magnet alloy that has excellent magnetic properties even as a bonded magnet. (Example) Examples of the present invention will be described in detail below. Example 1 Alloy samples No. 1 to No. 18 with the compositions shown in Tables 1 and 2
was melted by high frequency, coarsely pulverized using a Joe Crusher Brown mill, and then finely pulverized using a jet mill. In this case, _N2 gas was used as the grinding medium. Furthermore, the average particle size of the obtained particles was 5 μm. After orienting this fine powder in a magnetic field of 15KOe,
Compression molding was performed by pressing at right angles to the direction of magnetic field application at a pressure of ton/cm ² to obtain a plate-shaped powder compact measuring 10 mm in length, 10 mm in width, and 8 mm in thickness. Next, after sintering the powder compact, a permanent magnet is formed by heat treatment, and its residual magnetic flux density:
Br, coercive force: ₁ H _c , and maximum energy product:
(BH)max was measured and the results are shown in Tables 1 and 2. In addition, as the sintering conditions and heat treatment conditions of the powder compact, any one of the following conditions A, B, and C was used. A: The powder compact is sintered at 1100°C for 1 hour in an argon atmosphere, and then subjected to aging treatment at 600°C for 5 hours. B: After sintering the powder compact at 1080°C for 1 hour in an argon atmosphere, it was sintered at 650°C for 3 hours and at 550°C for 10 hours.
A two-stage aging process is performed. C: After sintering the powder compact in an argon atmosphere at 1050°C for 1 hour, aging treatment was performed at 550°C for 5 hours, and then controlled cooling was performed at a cooling rate of 1°C/min to room temperature. Comparative Example In order to compare with the magnet alloy of the present invention, the
Concerning the conventional R-Fe binary alloy having the composition shown in No. 19, No. 20 to No. 22, and alloys outside the scope of the present invention shown in No. 23 to No. 26 in Table 3. A permanent magnet was also manufactured in the same manner as in the above example. The magnetic properties were also measured in the same manner, and the results are also shown in Tables 2 and 3.

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[Table] Example 2 Bonded magnets were produced using alloy powder samples having the compositions shown in Table 4 below by the following method. First, a predetermined amount of elements were mixed, arc melted, and then homogenized at a temperature of 1000 to 1200°C for 18 hours. The obtained alloy is crushed to a particle size of 50 μm or less, and then heated at a temperature of 400 to 800℃ depending on the alloy composition.
Heat treatment was performed for several hours. Note that the alloys containing N or H were subsequently heat-treated in N ₂ and H ₂ atmospheres of 0.95 atm, respectively. Heat treatment conditions are 500℃ for 10 hours when containing N, 250℃ when containing _H2 ,
It warmed up in an hour. The obtained alloy powder was mixed with 2.5wt% epoxy resin and compression molded to form eight types of bonded magnets.
The residual magnetic flux density, coercive force, and maximum energy product of each bonded magnet are also listed in Table 4.

[Table] Example 3 Bonded magnets using alloy powders having the compositions shown in Table 5 were produced by the following method. First, a predetermined amount of elemental powder (powder particle size of rare earth elements is 0.5 mm or less, other elements are 5 to 40 μm) was mixed, and alloyed by a ball mill in an Ar atmosphere of 1 atm for 72 hours. The obtained alloy powder was heat treated at a temperature of 400 to 800°C for 30 seconds depending on the alloy composition. The alloys containing N or H were subsequently heat-treated in N ₂ and H ₂ gas atmospheres at 0.95 atm, respectively. Heat treatment conditions are 500℃ in case of N content;
The temperature was 2 hours, and the temperature was 250°C for 1 hour in the case containing _H2 . The obtained alloy powder was mixed with 2.5 wt% of epoxy resin and compressed into eight types of bonded magnets. The residual magnetic flux density, coercive force, and maximum energy product of each bonded magnet are also listed in Table 5.

[Table] [Effects of the Invention] As is clear from the results in the above tables, the rare earth iron-based permanent magnet alloy according to the present invention has high magnetic flux density,
It has remarkable effects such as having a high coercive force and a high energy product.

Claims (1)

[Claims] 1 General formula R _1- 〓 _- 〓X〓Fe〓 [However, R is one or more of Y, Ce, Pr, Nd, Sm, M, M (Mitshu Metal) X is C,
One or more of N, O, P, H, Al, and Si], and the ranges of α and β are defined by the following atomic ratios: 0.001≦α≦0.5 0.5≦β≦0.95 α+β<1.0 A rare earth iron-based permanent magnet alloy characterized by: