JPS594107A - Manufacture of rare earth and cobalt group magnetic material - Google Patents

Abstract

PURPOSE:To improve characteristics of magnetic alloy by making an alloy powder that consists of specified amounts of R (yttrium and rare earth elements), Fe, Cu, Zr and Co and forming the powder under pressure and sintering the formed powder. CONSTITUTION:By the method to form by powder metallurgy a magnetic alloy that belongs to the group of R2T17 (R represents yttrium and rare earth and T a transition metal) an alloy powder is made with 22.5-27.5wt% of R, 15.0- 23.0wt% of Fe, 3.3-5.0wt% of Cu, 1.5-3.5wt% of Zr, and balance of Co. This alloy powder is formed under pressure, and after sintering it at 1,170-1,230 deg.C it is subject to solid solution treatment at 1,130-1,200 deg.C. After this heat treatment at the same temperature as the sintering temperature and heat treatment at the same temperature as the solid solution treatment temperature are repeated. After this the product is held at 600-950 deg.C for 0.2-30hr, and then it is cooled under 500 deg.C with the cooling speed in the range of 0.05-5 deg.C/min.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an R--Co--Cu--Fe-based powder sintered permanent magnet material mainly containing tttrium and at least one of rare earth elements.

As R-Co-Cu-Fb alloy magnet materials, Cu1. It was usual to set the content to about Owj% or more + Fe 6 wt% or less. The reason for this is that the amount of Cu added was less than this.

By the way, + Cu is about 10 wt%, and Fe
If the Co content is less than 3 wt%, the Co content will inevitably increase, and in the conventional R-Co-Cu-Fe permanent magnets with a high Co content or less, in the manufacturing process, the RCo5 phase is increased after solution treatment. It had to be rapidly cooled to prevent precipitation. However, 1. Rapid cooling is itself a difficult operation and not only requires a large amount of cooling medium.

This also tends to cause cracks in the product and lowers the yield.

Unfortunately, in the conventional manufacturing method, multi-stage aging is performed after solution treatment, but in that case, a high coercive force can be obtained.
In the second quadrant of the 4πl5-H curve, the squareness was poor and the shoulders were rounded.

In a separate application filed on the same date (Japanese Patent Application No. 1983), the present inventors disclosed that in a powder sintered R2T17 magnet alloy, R was 22.5 to 27.5 wt%, Fe was 15 wt%,
1-23.0 wt%, CU 3.3-5.0 wt%
, a rare earth material that does not require rapid cooling after solution treatment while obtaining magnetic properties equivalent to or better than conventional ones in a composition with a low content of Co and Cu, with Zr being 165 to 3.5 wt + Co as the balance. We are proposing a magnetic alloy and its manufacturing method.

The present invention aims to solve the above-mentioned drawbacks by providing a manufacturing method that further improves the characteristics of a magnetic alloy having the above-mentioned composition.

The manufacturing method of the present invention uses an R2T17 magnet alloy (in particular, R is 22.5 to 27.5 wt% Fe is 15.0 to 27.5 wt%)
23.0 wt%, Cu 3.3 to 5.0 wt%,
An alloy powder containing 1.5 to 3.5 wt% of Zr and the balance of Co is made.

The alloy powder is press-molded and sintered at 1I70°C to 1230°C, followed by solution treatment at LI30°C to 1200°C, followed by heat treatment at the same temperature as the sintering flow rate and the solution treatment. This is a method for producing a rare earth cobalt magnet, which is characterized by repeating heat treatment at the same temperature as the treatment temperature, and then cooling at a temperature of 600° C. to 950° C. at a cooling rate of 0.2° C. below 500° C.

Next, the manufacturing method of the rare earth magnet disclosed in the above-mentioned Japanese Patent Application No. 1982 will be explained as Example 1.

Example] Sm is 22.0 to 28.0 wt%, Fe is 15.0 wt%.
0-24.0wt%, CI] is 3.0-5.0wt%
, Zr is 1.5 to 3.5 wt%.

The raw materials were prepared so as to form an alloy having the composition of the remainder Co, and the R2T17 alloy was melted in this mixture by high-frequency heating in an argon atmosphere. This alloy was coarsely ground and then finely ground to an average particle size of about 4 μm using a ball mill.

]ton//7 of this powder in a magnetic field of 10 koe
! It was molded at a pressure of The molded product was placed in an Ar atmosphere at 1170°C.
After sintering at ℃~1230℃ for 1~2 hours, 1130℃~
After solution treatment at 1200°C, heat treatment at 150°C with a blower
Air cooling was performed at 0°C to 1000°C/hour.

Next, this sample was held at 600 to 950°C for 02 to 30 hours, and then cooled to 500°C or less at 0.05 to 100°C. The magnetic properties when the sample composition is varied are shown in FIGS. 1, 2, 3, and 4, respectively.

In Figure 1, Sm is changed from 22.0 to 28.0 wt%,
Fe] 9. Owt%, Cu 4.5 wt%l
These are the characteristics when zr is 26wt% balance co. Second
The figure shows Sm26. Article Owt.

Fe was changed from 1.5.0 to 24.0 wt%, and Cu
4.8wt%.

This is a case where Zr is 2.4 wt% and the balance is co. Figure 3 shows Sm 26.3wt%, Fe 20.5
Change wt%+Cu to 30-50wt%, Zr 2.
There is a pumped ore with 5wt% and the balance Co. Figure 4 is 8m2
6.2 wt%, Fe 19.5 wt%.

Cu 4.9 wt%, Zr 1.5 to 3.5 wt%
% and the remainder is c.

This is the case. Regarding FIG. 1, when the rare earth metal (5) is less than or equal to 275%, Br and He decrease, and therefore (BH)maX also decreases. As a result, the amount of Sm is limited to 225-27.5 wt%.

Regarding FIG. 2, when the Fe content exceeds 23 parts, the coercive force IHC decreases and (BH)max also decreases rapidly. ! , rHC is less than 15 kOe
It disappears. Therefore, Fe is set at 15 to 23%.

Regarding FIG. 3, if the Cu amount is less than 3.3%, IHc will decrease, and if it is more than 5%, Br will decrease. Also C
When u is more than 5%, RCo5 decreases during cooling after solution treatment.
Phases tend to precipitate, requiring rapid cooling.

Therefore, Cu is 33-5. I will be in charge of Owt.

Regarding Figure 4, the Zr content is 15 to 3.5wt.
% range, Br and energy product (BH) m
aX will decrease.

The present invention uses R225 to 275wj% as shown in Example 1.
, Fe 15.0-23.0wt%, Cu 3.3
~5.0wt% + Zr1.5~3.5wt'% + C
The present invention provides a manufacturing method for improving the magnetic properties of a sintered magnet.

(6) Traditionally, sintering and solution treatment of rare earth cobalt magnets
As shown in the figure, treatment is generally performed using a one-time-temperature program, but the present invention.

In the composition as described above, sintering as shown in FIG.
After the solution treatment, a heat treatment as shown in FIG. 6 is performed. This heat treatment is carried out at the aforementioned sintering temperature (T1
) and held at the same temperature ('r3)-1:, further held at the same temperature (T4) as the solution treatment temperature (T2), and after cooling, heated again at T5''! (However, T5 is 60
0 to 950°C) and held for a holding time of 02 to 30 hours, then the cooling rate is below A)! By cooling with f, the squareness ratio is improved and (BH)maX is improved.

Examples of the present invention will be described below.

Example 1 An alloy containing 25.7 wt% Sm, 19.0 wt% Fe, 4.9 wt% Cu, and 2.4 wt% Zr with the balance being Co was melted, pulverized, and melted in the same manner as in Example 1 above. Magnetic field molding. This molded product was sintered at 1210° C. for 1 hour in an Ar atmosphere, and then subjected to solution treatment at 1180° C. for 1 hour. The characteristics at that time are a in Table 1, and the sample was heated to 1210°C.
After holding for 05 hours at 1180° C., heat treatment was performed for 1 hour. After holding this sample at 850°C for 6 hours.

It was cooled to below 500° C. at a cooling rate in the range of 0.005° C. to 5° C.h. The obtained magnetic properties were as shown in Table 1b.

Table 1 In this way, when comparing the case of sintering at 1210°C and the case of solution treatment at 80°C and the case of further heat treatment, the magnetic properties are much better with heat treatment.

Example 2 A molded body produced in the same manner as in Example 1 was sintered at 1200° C. for 2 hours in a +Ar atmosphere, and then subjected to solution treatment at 1165° C. for 1 hour. The magnetic properties at that time are as shown in a of Table 2. After holding this sample at 1210°C for 05 hours, it was heat-treated at 1165°C for 1 hour. This sample was held at 800° C. for 10 hours, and then cooled down to 400° C. in a trench at a cooling rate of 2° C./ki. The obtained magnetic properties were as shown in Table 2b.

Table 2 (9) Example 3 A molded body prepared in the same manner as in Example 1 was sintered at 1210°C for 1 hour in an Ar atmosphere, and then subjected to solution treatment at 11.80°C for 1 hour. . The magnetic properties at this time are a in Table 3.
This is the general rule. This sample was heat treated at 1180°C for 2 hours and then held at 830°C for 5 hours. Table 3 (10) Comparing the cases of sintering at 1210°C and solution treatment at 1180°C and the case of further heat treatment. Magnetic properties are much better with heat treatment.

This invention is an R2T17-based magnet alloy (here, R is "i").
l) Ram and rare earth elements T represent transition metals. ) by powder metallurgy, R is 22.5.
~27.5 wt%, Fe 15.0~23.0
wt%.

Cu: 3.3-5.0 wt%, Zr: 1.5-5.0 wt%
3.5 wt%.

The alloy with the balance being Co is molded and heated to 1170°C to 1230°C.
After sintering at 1130°C to 1200°C, heat treatment at the sintering temperature and solution treatment temperature is repeated, and then 02 to 30°C at 600°C to 950°C.
After holding for a period of time, it is possible to obtain a high coercive force by cooling with 005, and as a result, it has the excellent effect of obtaining a high energy product.

Note that cooling after solution treatment is not done by rapid cooling but by air cooling (150
0-b There was no precipitation of a different phase (RCo5). Therefore, there is no need to take the difficult method of rapid cooling.

[Brief explanation of the drawing]

1 to 4 are graphs showing the magnetic properties of an embodiment of the present invention, and FIG. 1 shows the maximum energy product (BH
)max, residual magnetic flux density Br, and coercive force IHc
Figures 2 to 4 show the changes in , respectively. (BH)m for the amount of Fe + Cu + and Zr
It is a graph showing changes in aX, Er + IHc. FIG. 5 is a diagram showing a temperature and time program for sintering and solution treatment in the production of conventional rare earth magnets, and FIG. 6 is a diagram showing a temperature and time program for heat treatment performed according to the present invention after solution treatment. Figure 1 Sm (wt%) Figure 2 Fe (vvt%)

Claims (1)

[Claims] 1, R2T, 7-based magnet alloy (here, R is Inotri ~ 27.5 wt%, Fe] 5.0 ~ 23.0
wt%, Cu 3, 3-5.0 wt%, Zr
An alloy powder containing 1.5 to 3.5 wt% of Co and the balance of
After sintering at 230°C, solution treatment is performed at 1.130°C to 1200°C, then heat treatment at the same temperature as the sintering temperature and heat treatment at the same temperature as the solution treatment temperature are repeated, and then A method for producing a magnet after being held at 600°C to 950°C for 02 to 30 hours.