JPS5848605A - Production of permanent magnet of rare earths - Google Patents

Abstract

PURPOSE:To improve the energy product of a magnet in the stge of producing an R2T17 magnet alloy consisting of Y as well as rare earth elements and transition metals by a powder metallurgical method by pressurizing the alloy in specific directions during sintering and solutionizing treatments to deform. CONSTITUTION:An R2T17 (R is Y, rare earth elements, T is transition elements such as Co) magnet alloy represented by Sm2(Co-Fe-Cu)17 is melted to ingot, and after cooling, the ingot is pulverized down to about 4mum average grain sizes. After the powder is molded by pressurizing in a magnetic field, the moldings are degassed in a vacuum, and while the moldings are pressurized so as to be deformed in the direction at a right angle to the direction where the powder is easy to magnetize during molding, in an Ar atmosphere, the moldings are subjected to a treatment under heating for the purpose of sintering and solubilizing and are then cooled. The R2T17 rare earth permanent magnet having high energy product without degradation in coercive force and residual flux density is obtained.

Description

[Detailed description of the invention] Yttrium, rare earth metals (R) and transition metals (T)
The present invention relates to a method for manufacturing a rare earth permanent magnet material that is an intermetallic compound of , and particularly to a manufacturing method that can improve the squareness ratio of R2T, 7-based rare earth permanent magnets.

Among the intermetallic compounds of R and T, RT5 and R2T,
It is well known that two types of No. 7 are useful as magnets. The former is a single-phase rare earth magnet represented by eSmCos, and is the most commonly used rare earth magnet. The latter is a two-phase separation type magnet represented by Sm2 (Co-Fe-Cu), 7 in which Co is partially replaced with other metals, and has recently been expected to be used as a high-energy product magnet.

Rare earth magnets are generally manufactured through the steps of melting raw materials, pulverization, orientation in a magnetic field, compression molding, sintering solution treatment, and aging heat treatment. Here, the dissolution is.

A predetermined amount of raw metal is heated in a high-frequency furnace or other furnace in an inert atmosphere. In the grinding step, the alloy obtained after melting is coarsely ground and finely ground to obtain alloy particles of 1 to 10 microns. Orientation in a magnetic field and compression molding are usually performed simultaneously when a mold is used. The magnetic field strength required for orientation is about 8 to 20 KOe, and the compression pressure is about 0.3 to 1.
0 iot! / About one. Sintering is done using Ar, He
in an inert atmosphere such as 1150~
It is carried out in a temperature range of about 1250°C. Since solution treatment usually proceeds at the same time as sintering, there is no need to perform a separate solution treatment step, but of course, there are cases where solution treatment is performed separately after sintering. Aging heat treatment is 750-900
This is done by maintaining the temperature within a range of approximately ℃.

The R2T17 rare earth magnet obtained by the conventional manufacturing method described above has a poor squareness ratio of the magnetic hysteresis curve.
Therefore, there was a drawback that a magnet with a high energy product ((BH)max) could not be obtained.

In the prior art, as mentioned above, after solution treatment.

The aging heat treatment is performed in order to cause spinodal decomposition by the solution treatment and to precipitate an appropriate RT phase in the R2T17 phase by the aging heat treatment. Formation of such a cell structure of R2';17 phase and RT5 phase is advantageous for improving coercive force (xHc). However, if the heat treatment time is extended for a long time, the residual magnetic flux density (Br) and the squareness ratio will decrease, and the energy product will decrease. The reason for this is thought to be mainly due to the change in the pinning energy of the domain wall due to the growth of the RT5 phase, which has a lower value of 4;

The present invention improves the drawbacks of such conventional manufacturing methods and produces high (BH)ra without deteriorating Br and He.
An object of the present invention is to provide a method for manufacturing an R2T17 rare earth permanent magnet having x.

The present invention is a method for manufacturing R2T, 7-base magnet alloy by powder metallurgy, in which the object to be sintered is pressed in a direction perpendicular to the pressing direction in the preceding compression molding step during the sintering solution treatment. It is characterized by pressure.

Nine embodiments of the present invention will be described below.

In the example, two alloys were melted by high frequency heating in an argon atmosphere. Next, this alloy was coarsely ground, and then finely ground to an average particle size of about 4 μm using a sol mill.

This alloy in the magnetic field of l Q KOe H1tor1/a/
It was molded at a pressure of 1.

After degassing the molded product in vacuum, in an Ar atmosphere,
The material to be sintered was subjected to solution treatment during molding at a temperature of 900° C. or higher.

After heat-treating this sintered body at 850°C for 7 hours,
℃'/'m I 300"c" at a cooling rate of less than n! It was cooled down. The magnetic properties of this sample and a sample that was not pressurized during sintering and solution treatment are shown in the table below.

It can be seen that the magnetic properties are improved by applying pressure during sintering in a direction perpendicular to the pressing direction during molding.

Procedural amendment (spontaneous) June 23, 1980 Director General of the Japan Patent Office Shima 1) Haruki-dono 1, Indication of the case Patent application No. 147441 of 1982 2
゜Name of the invention Method for producing rare earth permanent magnets 3 Relationship with the case of the person making the amendment Patent applicant 4, agent 〒105 5. Subject of the amendment 6, Contents of the amendment 1) Attached sheet 2) (1) Insert ``to deform'' after ``in the direction'' on page 4, line 5.

(2) Claim 1, which is characterized by the words "in a manner to deform" after "in the direction" on the third line from the bottom of page 5, R2T17-based magnetic alloy (here, R is yttrium and rare earth elements, T is (representing a transition element) by a powder metallurgy method.

A method for producing a rare earth permanent magnet, characterized in that during the sintering solution treatment, the object to be sintered is pressurized in a direction perpendicular to the pressing direction in the preceding compression molding step. .

Procedural amendment (voluntary) January/2nd, 1978 Mr. Kazuo Wakasugi, Commissioner of the Patent Office 1 Display of incident 1981 Patent Application No. 147441/2 Name of the invention Manufacturing method of rare earth permanent magnet 6. Person making the amendment Name Tohoku Metal Industry Co., Ltd. 4 agents〒105 5 Target of correction 1) Claims column of the specification 2) Detailed description of the invention in the specification 6. Contents of amendment 1) As shown in the attached sheet.

21, page 4, line 4, "pressing direction" is corrected to "direction of easy magnetization of powder".

(2) Correct "pressure direction" in the third line from the bottom of page 5 to "direction of easy magnetization of powder".

(Attachment) 1. In a method for manufacturing R2T, a 7-base magnet alloy (where R represents yttrium and a rare earth element, and T represents a transition element) by a powder metallurgy method, the sintered material is A method for producing a rare earth permanent magnet, comprising deforming the powder in a direction perpendicular to the direction of easy magnetization of the powder in the preceding compression molding step.

Claims (1)

[Claims] IR2T, 7-series magnet alloy (R means I) IJium and rare earth elements, T represents a transition element. ) by powder metallurgy, the rare earth permanent magnet characterized in that during the sintering solution treatment, the sintered object is pressed in a direction perpendicular to the pressing direction in the preceding compression molding step. manufacturing method.