JPH02263937A - Manufacture of rare earth magnetic alloy - Google Patents

Abstract

PURPOSE:To manufacture a rare earth magnet having reduced dispersion of characteristics and increased coercive force by subjecting a rare earth-contg. Co-Fe-Cu series alloy having specified compsn. to pulverizing, forming, sintering and solution treatment, thereafter controlling its cooling and executing aging treatment. CONSTITUTION:An alloy having the compsn. shown by R (Co1-a-b-cFeaCubMc)z is pulverized (in the formula, R denotes one or more kinds among rare earth elements, M denotes at least one kind among Ti, Zr, Hf and Nb and 0.05<=a<=0.35, 0.03<=b<=0.15, 0.005<=c<=0.05 and 6.5<=z<=8.7 are regulated). The alloy powder is formed in a vertical direction to the magnetic field and is sintered. Next, solution treatment is executed at 1100 to 1200 deg.C for >=1hr holding time. After that, the alloy is cooled to <=500 deg.C at 0.5 to 1.5 deg.C/sec cooling rate and aging is executed. In this way, a rare earth magnet of high capacity having >=25KOe coercive force Hc can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing rare earth magnet materials.

[Conventional technology]

Rare earth magnets made of the rare earth element R and cobalt are used particularly in equipment that requires miniaturization and equipment that requires a strong magnetic field. Recently, there has been an increasing demand for high-performance magnets, and magnets with high coercive force and Hc are required for devices that are sometimes made thinner, subjected to reverse magnetic fields, and exposed to high temperatures. Examples include traveling wave tubes for communication satellites and rotary machines for aircraft. Until now, it was RCo.

was using. Although IHc is high, the energy product (B)I
), □ ~ 18 MGOe, which is low and cannot sufficiently cope with miniaturization. Therefore high HHc, J of (BH)saw
It is necessary to use a Co+7 magnet.

Figure 1 shows a general manufacturing process for R, Co, and magnets.

The manufacturing method uses rare earths R, Co, etc. to achieve the target composition.
, Fe, Cu, and Zr are mixed, and then this mixture is melted to obtain an ingot. This ingot is coarsely crushed and finely crushed to obtain raw material powder. This raw material powder is 5 to 1
Press molding is performed in a magnetic field of about 5 KOe, and the molded product is
Sintering is performed at a temperature of 0 to 1230°C for about 1 to 2 hours. Thereafter, solution treatment is performed at 1100 to 1200°C for 1 hour or more. Then cool quickly. 750-950℃ after solution treatment
After aging for 5 hours or more, further In this case, only the vicinity of rHc 10 koe can be obtained from FIG. Furthermore, when manufactured at a speed of 1° C./sec or higher as described in Japanese Patent Application Laid-Open No. 58-136757, the magnetic properties vary widely in the range of coercive force and HClO to 30 kOe, which is a quality problem.

An object of the present invention is to provide a method for manufacturing a high-performance rare earth magnet with a coercive force +Hc of 25 to 30 kOe while reducing such variations in characteristics.

[Means for solving problems]

The present invention reduces the cooling rate after solution treatment during the manufacturing process to 0.
This is a method for manufacturing rare earth magnets, which is characterized by controlling cooling at a rate of 5 to 1.5° C./sec, performing optimal aging treatment, and increasing Hc.

In the present invention, the relationship between the cooling rate after solution treatment and Hc is shown in FIG. In Figure 1, the cooling rate is 0.5 to 1.
．． More than 25 kOe can be obtained at 5°C/sec, especially 1
．． 3QkOe is obtained at 0°C/sec. Material 5I12
CO+7, (Smo, s CEO, 5)zco17,
Even in CegCoH, the cooling rate is 0.5-1.5℃/s
ec to obtain Hc of 25kOe or more. For reference, at the cooling rate of solution treatment up to now, which is called rapid cooling, of 2.2° C./sec or more, an IQ of only around kOe can be obtained. Note that the composition R (GO
For each element in +-5-b-cFe, CubMc)w, the ratio of the total amount of other elements to the total amount of rare earth elements is 2
When is less than 6.5, Hc decreases and Br also decreases due to a decrease in saturation magnetization. Furthermore, if 2 exceeds 8.7, Hc decreases rapidly, so 6.7≦z≦8.7 is appropriate.

Fe has the effect of increasing saturation magnetization and increasing Br, but this effect is small when a is less than 0.05;
If it exceeds 35, Hc decreases, so 0.05≦a≦0
．． 35 is appropriate.

Cu is an element necessary for causing a two-phase separation reaction, and has the effect of increasing IHc. however,
If b is less than 0.03, the two-phase separation reaction will not proceed sufficiently, and sufficient Hc for a magnet will not be obtained, and if b is 0.
．． If it exceeds 15, the saturation magnetization decreases and Br decreases, so 0.03≦b≦0.15 is appropriate.

M is at least one of Ti, Zr, Hf, and Nb;
By adding seeds 1. It has the effect of increasing Hc. However, if C is less than 0.005, this effect will not be noticeable, and if C exceeds 0.05, Hc will decrease rapidly, so 0.005≦X≦0.05 is suitable.

〔Example〕

Hereinafter, the present invention will be explained in detail using Examples.

Example 1 First, the composition Sm (Cobst, Feo, zcuo,
ossZro, 624) It was dissolved to a particle size of 8.3, and then coarsely ground to 30 mesh or less. The coarsely ground powder was finely ground using a jet mill to give an average particle size of 3.7μ.

This raw material powder was molded perpendicular to the magnetic field. Sintering at 1200℃
I went there for an hour. Solution treatment was performed at 1180° C. for 2 hours. After that, 0, 5~1.5℃/se shown in Figure 2
Controlled quenching was performed at c to 500°C. The sample was aged at 830°C for 2 hours and then cooled to 300°C at 1°C/min. This aging process was repeated twice. As a result of magnetic measurement of the obtained sample, Br: 10800 G mHc
: 95000e rHc : 270000e,
(BH)...28.5 MGOe was obtained.

Example 2 Composition Sm6.5ceo, s (Cobmt Fea,
zcuo, osJro, 025)? , ? A raw material powder was prepared in the same manner as in Example 1. The raw material powder was molded parallel to the magnetic field, sintered at 1170"C for 2 hours, and then solution treated at 1140"C for 1 hour.
Controlled cooling was performed to 500°C at ~1.5°C/sec. The sample was held at 740°C for 2 hours and then heated at 1.0°C/min for 300°C.
Cooled to ℃. The sample was again held at 730°C for 24 hours and then subjected to two-stage aging by cooling to 300°C at a rate of 0.6°C/min. Its magnetic properties are Br96000e, sHc
85000e rHc 255000e(BH)s
ex 22.5 MGOe was obtained.

Example 3 Composition Ce (CobaLFeo, zcuo, ollZ
ro, ago)? , o in the same manner as in Example 1 to prepare raw material powder. The raw material powder was molded perpendicular to the magnetic field, sintered at 1140°C for 2 hours, and solution treated at 1120°C.
for 1 hour, then at 0.5-1.5℃/sec for 5
Controlled cooling was carried out to 00°C.

The sample was held at 730°C for 4 hours and then heated to 300°C.
After cooling at 0°C/min and then holding at 720°C for 11 hours,
Two-stage aging was performed by cooling to 300°C at a rate of 5°C/min. The magnetic properties of the sample are Br9500 Gm Hc8000
0e IHc 250000e (BH),,, 22
Obtained MGOe.

〔Effect of the invention〕

According to the present invention, Hc 10 kOe was obtained by rapid cooling after solution treatment (at least 2.2°C/sec), but when cooling after solutionization is controlled at 0.5 to 1.5°C/sec, r Hc 2
More than 5 kOe can be obtained and a maximum of 30 KOe can be achieved.

FIG. 2 shows the relationship between the cooling rate after solution treatment and the coercive force I He according to the present invention.

[Brief explanation of drawings]

Claims (1)

[Claims] General formula R(Co_1_-_a_-_b_-_cFe_a
Cu_bM_c)_z (where R is at least one rare earth element or a combination of two or more, M is Ti, Zr, H
at least one of f, Nb, and 0.05≦a≦0.3
5, 0.03≦b≦0.15, 0.005≦c≦0.0
5, 6.5≦z≦8.7) In a production method in which an alloy having a composition shown by
temperature range for at least 1 hour, then 50℃
1. A method for producing a rare earth magnet alloy, comprising cooling to 0° C. or lower at a cooling rate of 0.5 to 1.5° C./sec and aging to obtain _IHc of 25 kOe or more.