JPS61114502A - Manufacture of samarium-cobalt magnet powder for resin magnet - Google Patents

Abstract

PURPOSE:To manufacture SmCo5 magnet powder by performing a reduction- diffusing method without adding other elements by a method wherein the impurities containing a samarium oxide, the percentage of content of the samarium oxide, and the percentage of content of the samarium contained in the magnet powder are specified properly. CONSTITUTION:The samarium oxide, to be used as the material for magnetic powder, contains lanthanum, cerium, praseoxymium and neodymium of 1.3wt% or below as impurities. The above-mentioned materials are contained in the ratio of 1.7wt% in total. The compounding of materials is performed in such a manner that the samarium contained in the magnetic powder becomes 32.7-33.4wt%. By compounding the materials as above-mentioned, the magnet powder having excellent magnetic characteristics can be stably manufactured at low cost by performing a reduction-diffusing method without adding other elements.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for stably and easily producing 5inos-based magnet powder, which has excellent magnetic properties and is suitable for resin magnets, by a reduction diffusion method. Regarding.

[Conventional technology]

Conventionally, to produce 5IIICO5-based magnet powder for resin magnets, a mixture of samarium oxide and cobalt powder is heated, and the samarium oxide is mixed with a reducing agent such as vapor or solid calcium. The so-called reduction-diffusion method involves diffusing the samarium produced by reduction into the cobalt powder, pouring the resulting reaction product into water to form a slurry, and treating the slurry with water and an acid aqueous solution. It has been adopted. In order to improve the magnetic properties of the SmC:os magnet powder produced by such a method, a method of adding elements such as praseodymium and germanium is known.

[Problem that the invention seeks to solve]

However, the above-mentioned addition method is complicated, and the magnetic properties of the obtained SmCo5-based magnet powder tend to vary and become unstable.

From this point of view, the present inventors aim to stably and easily produce SmCo5-based magnet powder, which has excellent magnetic properties and is suitable for resin magnets, by a reduction diffusion method without adding other elements. We have conducted extensive research to find a way to do this.

[Means for solving problems]

As a result, we used samarium oxide as a raw material that contained lanthanum, cerium, praseodymium, and neodymium as impurities at 1.3% by weight or less, and the total of these was 1.7% by weight or less, and The composition is such that samarium in the manufactured SmCo5 magnet powder is 32.7.
It has been found that the above object can be achieved by adjusting the amount to 33.4% by weight.

[For production]

The present invention will be explained in more detail below.

The samarium oxide used as a raw material in the present invention is limited to containing impurities of lanthanum, cerium, praseodymium, and neodymium in an amount of 1.3% by weight or less, and a total of 1.7% by weight or less. If at least one of lanthanum, cerium, praseodymium, and neodymium contained exceeds 1.3% by weight, or the sum of them exceeds 1.7% by weight, the magnetic properties of the produced magnet powder, especially This is because the coercive force decreases rapidly.

Next, the raw materials were blended so that samarium in the manufactured magnet powder was 32.7 to 33.4% by weight. niS [llC01? Excessive phase formation causes a sudden drop in coercive force.On the other hand, when it exceeds 33.4% by weight, Sm2C
This is because the ot phase is generated and the residual magnetic flux density decreases.

The reaction products obtained from the reduction-diffusion reaction are subjected to solution treatment,
It is necessary not to perform heat treatments such as aging treatment and homogenization treatment. When such heat treatment is performed, the magnetic properties are lower than when no heat treatment is performed.

This decrease in magnetic properties is caused by heat treatment when samarium in the magnet powder falls within the above limited range of 32.7 to 33.4.
Even if it deviates from the weight% or is within this range, Sm
In addition to Co5 phase, S mIC017, Sm2Cot, 5I
It is presumed that this is due to the formation of phases such as IIC03.

〔Example〕

Hereinafter, the present invention will be explained with reference to examples.

Example 1 132 to 147 g of 5IIltO1 powder containing La, Ce, Pr, and Nd as impurities as shown in Table 1, C
o powder.

(Blank below) Table #51 This pot was placed in a reaction apparatus, heated in Ar gas and held at 980°C for 1 hour, then heating was stopped and cooled to room temperature. The resulting reaction product was mixed with water and pH approx.
．． 5 of dilute acetic acid to remove the contained CaO1 and unreacted C.
a was separated and removed. The obtained powder was dried after the adhering moisture was replaced with alcohol. Furthermore, these powders were charged into a rotary ball mill, filled with ethyl alcohol, and heated for 2 hours.
Pulverized for hr. The composition of the powder thus obtained is shown in Table 2. When some of these powders were subjected to X-ray analysis, test N
It was found that both samples 0 and 1.3 were composed of a single-phase SmCo1 intermetallic compound. However, test No. 13
．． 16 is 5111cO+ in addition to SmCo5 phase.
, phase was observed, and in test Nos. 15 and 17, in addition to the 5IIICos phase, 5IIIC03 phase and 5ffit
A COr phase was observed.

! 8.5% by weight of polyamide resin (nylon 6) was added by external cutting to the magnet powder prepared as shown in the IP & 2 table above.
After addition, kneading, and pelletizing, injection molding was performed in a magnetic field of 15 KOe. Table 3 shows the results of measuring the magnetic properties of the obtained resin magnet.

Comparative Example 1 The Sm*Os powder, Ca powder, and Ca grains of Test No. 1 of Example 1 were mixed in a proportion of 137 g, 242 g, and 70 g, respectively, and after being held at 980°C for 1 hour, the mixture was heated to 1150°C.
It was operated in exactly the same manner as in Example 1 except that the temperature was raised to 850° C., held at that temperature for 1 hour, then cooled to 850° C., held at that temperature for 6 hours, and cooled to room temperature. Table 4 shows the composition of the obtained magnet powder and the magnetic properties of the resin magnet.

Table 4 Comparative Example 2 The procedure was exactly the same as in Comparative Example 1 except that 5l11203 powder of Test No. 35 of Example 1, Ca grains, and Ca grains were mixed in the proportions of 145 g, 243 g, and 172 g, respectively. Table 5 shows the composition of the obtained magnet powder and the magnetic properties of the resin magnet.

Table 5 [Effects of the Invention] As is clear from the above, the present invention produces a SmCo5-based magnet suitable for resin magnets, which has excellent magnetic properties such as residual magnetic flux density, coercive force, and maximum energy product, using the reduction diffusion method. The powder can be manufactured without heat treatment by using samarium oxide raw materials with a limited amount of impurities and by blending the powder so that the samarium in the powder has a limited composition. This heat treatment is particularly likely to change the composition of samarium, which is a major element, and therefore the present invention, which can stably and easily produce 5III CO6 magnet powder suitable for resin magnets, has great industrial significance. It is large.

Claims (1)

[Claims] (1) After heating and reducing a mixture of samarium oxide and cobalt powder and diffusing the produced samarium into the cobalt powder, the resulting reaction product is poured into water to form a slurry. In a method for producing magnetic powder by treatment with water and an acid aqueous solution, the samarium oxide contains lanthanum, cerium, praseodymium, and neodymium in an amount of 1.3% by weight as impurities.
In the following, use materials whose total content is 1.7% by weight or less, and perform the blending so that samarium contained in the magnet powder is 32.7 to 33.4% by weight. A method for producing samarium-cobalt magnet powder for resin magnets, characterized by: