JPS6036633A - Production of magnet consisting of rare earth cobalt - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing rare earth cobalt magnets, particularly R2T1
This invention relates to improvement of magnetic properties when manufacturing a 7-series magnetic alloy by powder metallurgy.

The present invention relates to a new and improved method for manufacturing rare-L class cobalt magnets that allows permanent magnet materials with high performance magnetic properties to be easily obtained. R from 22.5
27.5 wt%, Fe 15.0 to 23. Owt%,
Cu: 3.3-5°3wt%, Zr: 1.5-3.
An alloy containing 5 wt% and Co as the balance was formed and heated to 1170°C.
After sintering with the above, 113
After lowering the temperature to 0°C to 1200°C and performing solution treatment, it was held at 600 to 950°C for 02 to 60 hours, and then
It is characterized by cooling to 500°C or less at a cooling rate of 0°C/H or less.

To explain this, the present invention is based on various researches on rare earth cobalt magnets in order to obtain permanent magnets with better magnetic properties.
In particular, they discovered that by employing specified heat treatment conditions, a high-performance permanent magnet, which was previously considered impossible, could be obtained, leading to the completion of the present invention.

Fact” - According to the method of the invention described, 29.5 MGOe
The advantageous effect is that permanent magnets with a maximum A-Lugie product reaching .

To explain this in more detail, first, the heat treatment conditions, especially the temperature, need to be strictly controlled.

First is the sintering process, which is over 1170°C.

It is necessary to perform the sintering preferably within the range of 1170°C to 1230°C, and when the sintering temperature is lower than this, the residual magnetization is low (1); when it is high, the residual magnetization is large, but the coercive force and the angle of the hysteresis curve are This results in disadvantages such as reduced moldability.

It goes without saying that the sintering process (the same applies to the subsequent heat treatment process) must be performed in a vacuum or in an inert gas atmosphere such as argon.

After the sintering process, the molded product enters the ninth cooling process, and in the present invention, the cooling rate is also an important factor that must be accurately controlled.

The temperature is lowered to 1130°C to 1200°C at a cooling rate of 150°C/H or less, and after solution treatment, the temperature is reduced to 600°C to 950°C.
After holding for 0.2 to 60 hours, the temperature is cooled to 500°C or less at a cooling rate of 300°C/H or less. When the cooling rate is faster than the above, the coercive force and residual magnetic flux density as well as the maximum energy product decrease.

Next, five examples of the present invention will be listed, but these are not intended to limit the present invention.

<Example 1> Sm is 22.0-28.0 wt%, Fe is 15.0-28.0 wt%
24.0 wt%, Cu 3.0 to 5.0 wt%,
In an argon atmosphere such that Zr was 1.5 to 3.5 wt% and the balance was co.

The R2Tj7 alloy was melted by high frequency heating.

This alloy was coarsely ground and then finely ground to an average particle size of about 47 zm using a ball mill. This powder was molded at a pressure of 1 pan/ca in a magnetic field of 10 KOe.

After sintering the molded product at 1j70°C to 1260°C in an Ar atmosphere, solution treatment was performed at 1130°C to 1200°C.

Next, this sample was held at 600 to 950°C for 0.2 to 50 hours, and then cooled to 500°C or less at a cooling rate of 5°C/min or less.

Figures 1 and 2 show the composition and magnetic properties of this sample.

It is shown in FIGS. 5 and 4. Figure 1 shows Sm22.0-28.
0wt%, Fe19.0wt%, Cu4.5wt%,
Zr: 2.6 wt%, balance: co. Figure 2 shows Sm2
6.0wt%.

Fe 15.0-24. Owt, Ou 4.8w
t%, Zr2゜4wt%.

The remainder is CO. Figure 6 shows Sm26.3wt%, Fe2
O, 5wt%, Ou 3.0-5. Owt%, Zr
2.5 wt%, balance CO. Figure 4 shows Sm26.2
wt%, Fej9.5wt%.

Cu 4.9 wt%, Zr 1.5-3.5 wt%
, the remainder is co.

Regarding FIG. 1, when Sm is used as the rare earth metal R, if the amount is 28% or more, Br and He decrease, and therefore (BH)max also decreases.

Regarding FIG. 2, when the Fe content becomes more than 23% = 4-, the coercive force decreases and BH)max also decreases rapidly.

Regarding FIG. 6, if the Cu amount is less than 6.3%, He will decrease, and if it is more than 5%, Br will decrease.

Regarding Figure 4, the Zr content is 1.5 to 3.5 wt%.
Br and energy product (BH)ma exceeds the range of
x will decrease.

<Example 2> Sm is 26.0 wt%, Fe is 19.2 wt%, Cu
An alloy consisting of 4.7 wt% Zr, 2.4 wt% Zr, and the balance Co was melted, pulverized, and magnetically formed in the same manner as in Example 1.

This molded body was sintered at 1215° C. for 1 hour in an Ar atmosphere, and then cooled to 1180° C. at a cooling rate of 50 to 200° C./H to undergo solution treatment. The solution treatment was completed one hour after the temperature started to decrease from the sintering temperature.

After holding this sample at 850℃ for 5 hours, 300℃/H
It was cooled to 500°C or less at the following cooling rate.

Its magnetic properties are shown in FIG.

As shown in FIG. 5, when the temperature decreasing rate is 150° C./Hr or more, the coercive force and the maximum energy product (BH) max decrease.

As described above, the present invention relates to an R2T17-based magnet alloy (where R represents yttrium and a refined element, and T represents a transition metal).

) by powder metallurgy, R is 22.
5-27.5 wt%, Fe 15.0-23. Owt%
+011 from 3.3 to 5. []wt%, Zr 1.
An alloy containing 5 to 3.5 wt% Co as the balance was formed into 1
After sintering at 170°C or higher, the temperature was lowered to 1160°C to 1200°C at a cooling rate of 150°C/H or lower, and solution treatment was performed, followed by holding at 600°C to 950°C for 0.2 to 30 hours. By cooling to 500°C or less at a cooling rate of 300°C/H or less, a high coercive force can be obtained, and as a result, it has the excellent effect of obtaining a high energy product.

[Brief explanation of drawings]

1 to 4 are diagrams showing the characteristics of magnets with different compositions in Example 1, and FIG. 5 is a diagram showing the characteristics of magnets of different compositions in Example 1. 3 is a diagram showing magnet characteristics of Example 2. FIG. Fig. 1 Fig. 2 Fe (wt, %) Fig. 3 Cμ (wt'yo) Fig. 4 Zy (wt%) Temperature fall Stray degree (0C/Hr)

Claims (1)

[Claims] 1. In producing an R2T17-based magnetic alloy (where R represents yttrium and a rare earth element, and T represents a transition metal) by a powder metallurgy method, R is set to 22.5 to 27.5.
wt%, Fe from 15.0 to 23.0 wt%. Ou from 3.3 to 5. Owt%, Zr 1.5-3.5
wt%, C. After molding the alloy powder with the remainder as
After cooling down to 00℃ and performing solution treatment,
After holding at 950℃ for 0.2 to 30 hours, 600℃/H
A method for producing a rare earth cobalt magnet, characterized by cooling to 500°C or less at the following cooling rate. Margin below