JPH0451041B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field to which the invention pertains] The present invention relates to a polymer composite magnet,
In particular, the present invention relates to a method for manufacturing a polymer composite magnet using rare earth magnet powder. [Prior art] Polymer composite magnets are made by dispersing magnetic powder in polymer resin, and have various characteristics not found in cast magnets, sintered magnets, etc., such as elasticity and ease of processing. It is equipped with and used in various fields. However, since they are made of magnet powder and non-magnetic resin, they have the disadvantage of having lower magnetic properties than sintered magnets and the like. Therefore, magnet powder is required to have higher magnetic properties. Conventional composite magnets of R ₂ T ₁₇ rare earth magnets are made by melting raw materials, obtaining alloy ingots, solution treatment, aging,
It was manufactured by pulverizing the powder, mixing it with polymer resin, and molding it. According to this method, the ingot contains many different phases, and even with long-term solution treatment, it is not completely homogenized, and the magnetic properties vary widely even within the same ingot. The magnetic properties of a composite magnet using these pulverized powders deteriorate. [Object of the Invention] The present invention improves the magnetic properties of a polymer composite magnet using a rare earth magnet of the type R ₂ T ₁₇ , which is known to have a high residual magnetic flux density (Br) among rare earth magnets. The purpose of this invention is to provide a method for producing water. [Structure of the Invention] The method for producing a rare earth cobalt-based polymer composite magnet of the present invention includes an R ₂ T ₁₇ alloy (where R is at least one of yttrium and a rare earth element, and T is
Represents transition metals including Co. ) ingot of 0.03~2.0mm
It is characterized by molding coarsely crushed alloy powder in a non-magnetic field, sintering the molded body, subjecting it to solution treatment, aging, re-pulverizing, mixing the re-pulverized powder with polymer resin, and molding. That is. In the method of the present invention, if the pulverized particle size of the ingot is large, it is difficult to homogenize the magnet alloy sufficiently, and the coercive force _I H _C and squareness tend to decrease. If it is too small, the alloy is highly reactive, so oxidation of the surface becomes noticeable, which not only causes compositional fluctuations due to sintering, but also due to the presence of oxidized non-magnetic field inclusions.
This causes a decrease in Br. [Operation and Effect of the Invention] According to the method of the present invention, compared to the conventional method,
By forming coarse powder obtained by coarsely pulverizing an alloy ingot into a molded body in the absence of a magnetic field, the contact area between particles is significantly improved compared to the powder state, and through this area, elements can be diffused during sintering etc. As the magnet alloy progresses, the homogenization of the magnet alloy progresses compared to the non-molded state.
Not only can magnetic powder with less variation in magnetic properties be obtained and a polymer composite magnet with high magnetic properties obtained, but also the heat treatment process such as solution treatment can be significantly shortened, making it extremely useful industrially. It has advantages. Examples will be described in detail below. Example 1 Sm is 26.5wt%, Fe is 14.9wt%, Cu is 9.5wt%,
Adjust the raw materials so that Zz is 1.5wt% balance Co,
It was melted by high frequency heating in an argon atmosphere to obtain an ingot. After crushing this ingot to 1.0mm or less, the diameter is 50mm,
It was molded into a disk shape with a height of 30 mm using a pressure of 0.5 ton/cm ² . This green compact was sintered at 1200° C. for 1 hour in an argon atmosphere, then solution treated at 1180° C. for 1.5 hours and rapidly cooled. This sintered body was maintained at 800°C for 1 hour and then cooled at 1°C/min for aging. This sintered body has a thickness of 15μm
The powder was ground in a ball mill to a powder with an average particle size of . Table 1 shows the magnetic properties of a polymer composite magnet obtained by kneading 10 wt % of nylon 12 into this magnet powder and then injection molding it in a 15 kOe magnetic field at high temperature in comparison with the conventional method. In the conventional method, an ingot is held at a solution temperature for a long time until its magnetic properties reach saturation, and then aged, and the rest is made into a composite magnet in the same manner as in the example.

[Table] By the method of the present invention, (BH)max is approximately doubled. Example 2 Sm25.0wt%, Fe19.0wt%, Cu4.9wt%,
An alloy ingot was obtained in the same manner as in Example 1 so that Zr was 2.5 wt% and the balance was Co. This ingot
After pulverizing to 0.5 mm or less, it was molded in the same manner as in Example 1, sintered at 1210°C for 2 hours, and then solution treated at 1180°C for 5 hours and rapidly cooled. This sintered body was heated to 800℃.
After holding for 10 hours, it was cooled at a rate of 1° C./min and aged. This sintered body was pulverized in the same manner as in Example 1, then kneaded with 10 wt % polypropylene, and then formed into a composite magnet in the same manner as in Example 1. The results are shown in Table 2.

[Table] A significantly higher (BH)max was obtained by the method of the present invention. Example 3 Sm is 26.3wt%, Fe is 15.0wt%, Cu is 9.0wt%,
An alloy ingot was obtained in the same manner as in Example 1 so that Zr was 1.4 wt% and the balance was Co. This ingot
Powder with a particle diameter of 0.02 to 3.0 mm or less was prepared, and molded and heat treated in the same manner as in Example 1. Using this sintered body, a polymer composite magnet was obtained in the same manner as in Example 2. The results are shown in the figure. When the particle size of the powder obtained by crushing the ingot is 0.03 mm or less, the magnetic properties deteriorate significantly due to oxidation, and when the particle size exceeds 2 mm, _{the I} H _C decreases significantly due to the problem of homogenization. According to the above examples, the maximum grain size of the ingot is 0.03~
It can be seen that the effect of heat-treating a molded body of powder crushed to 2.0 mm and turning this magnet powder into a polymer composite magnet is extremely large.

[Brief explanation of the drawing]

The figure shows the relationship between the residual magnetic flux density Br and _the coercive force _IHC of the composite magnet in Example 3 of the present invention, and the maximum particle size of the powder obtained by crushing the ingot.

Claims (1)

[Claims] 1 R ₂ T ₁₇ -based magnet alloy (where R is at least one of yttrium and rare earth elements, T is
Represents a transition metal containing Co. ), the ingot of the alloy is coarsely pulverized to a maximum particle size of 0.03 to 2.0 mm, the powder is molded in the absence of a magnetic field, and the molded body is sintered and solutionized. A method for producing a rare earth cobalt-based polymer composite magnet, which comprises: after aging treatment and further pulverization, mixing a polymer resin with the magnet powder and molding the mixture.