JPH04125908A - Manufacture of bond magnet - Google Patents

Abstract

PURPOSE:To improve magnet characteristics by making rare earth element R composition value of liquid quench alloy powder larger than or equal to specified %, and making the loadings lower than or equal to specified %. CONSTITUTION:Ingot whose main component is R2Fe14B phase being a solid phase is heat-treated for homogenizing, granulated, and pulverized, thereby obtaining powder. Liquid quench alloy is obtained from R-rich alloy; said alloy is pulverized and mixed with alloy powder whose main component is R2Fe14B phase; a molded object is obtained by magnetic field molding. The mixing ratio is as follow; powder of liquid quench alloy wherein R composition is 40-100wt.% is 0-70vol%, and the residual part is R2T14B based alloy powder. By heat-treating this molded object, magnet characteristics are generated. By impregnating this molded object with resin and curing it, a bond magnet is obtained.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to bonded magnets made of magnetic powder as a binder, especially R2T and 4B based alloys as magnetic powder.
The present invention relates to a method for manufacturing a 2T, 4B bonded magnet.

[Prior art and problems to be solved by the invention] Conventionally,
Permanent magnetic materials are used in a wide range of fields, from various electrical products to small precision instruments and various actuators, and are considered one of the two most important electrical and electronic materials. In recent years, high-performance permanent magnets are required due to the demand for smaller and more efficient equipment. In response to these demands, demand for rare earth magnets with high properties has been rapidly increasing in recent years. Here, rare earth magnets are divided into sintered magnets and bonded magnets. Bonded magnets have the following characteristics that cannot be obtained with sintered magnets, as listed below, and their demand for various actuators has increased rapidly recently. ing.

B. Thin-walled products can be easily obtained.

It is less brittle than sintered magnets.

C. Excellent mass production.

As a method for manufacturing R2T14B bonded magnets, R
There is a method of mixing a binder with a ribbon powder obtained by rapidly cooling and solidifying a -T-B base alloy, and forming it into a bonded magnet. Basically, the ribbon obtained by rapidly cooling and solidifying this Since it is magnetically isotropic, the magnetic properties of the bonded magnet obtained by this method are low.

Next, it was discovered that the powder obtained by pulverizing the compact obtained by subjecting the ribbon to hot upsetting showed strong magnetic anisotropy and had a high energy product. Although the development of magnets is progressing, this powder easily breaks at the laminated interface during upsetting, and because it is flat, orientation during molding is insufficient, and the magnetic properties of bonded magnets are not sufficient. This is the current situation.

On the other hand, it has been proposed to manufacture bonded magnets by mixing and molding powder obtained by pulverizing R2T I4B sintered magnets with a binder, but the coercive force of the pulverized powder is extremely low due to distortion or damage due to mechanical stress caused by pulverization. Because of this, the characteristics remain low.

In order to improve this, attempts have been made to heat-treat the molded body of crushed powder to eliminate stress strain, or to recover the coercive force by recovering the damage, and then impregnating the molded body with resin to make a bonded magnet. However, the magnetic properties are insufficient, the number of steps is large, and there are problems in terms of cost.

A method has also been attempted in which a R2Tl4B ingot is heat-treated, the pulverized powder is made into a compact, heat-treated, and then impregnated with resin to form a bonded magnet, but the magnetic properties are insufficient. This is the R-Fe present in the ingot.
The solid solution phase is present in an extremely small amount compared to the main phase Nd2Fe, 4B phase, the nonmagnetic phase NdFe4B4 phase, and the oxide phase (34vt%N d -1vt%B -Fe b
(The amount of R-Fe solid solution phase in the at alloy is 6 vol% or less) or the particle size distribution becomes wide due to poor crushability, or the R-Fe solid solution phase powder, which becomes the core of the liquid phase during sintering, and the solid This is because uniform mixing with the R2Fe and 4B phase powders, which are the phases, is not possible, so one structure becomes non-uniform and the properties are not improved.

Therefore, one technical problem of the present invention is to provide an R2T14B compression-molded bonded magnet having excellent magnetic properties.

[Means for solving the problem] In order to obtain excellent magnetic properties in the R2T14B bonded magnet, it is necessary to make the structure uniform by uniformly dispersing the R-Fe solid solution phase in the compact. 1 As a result of intensive research on this point, the present inventors found that R-rich liquid quenched alloy powder and alloy powder obtained from ribbons (amorphous and microcrystalline) and mainly R2T
, 4B solid solution components are mixed and molded into a molded body, which is then heat-treated and then impregnated with resin to form a bonded magnet, thereby producing an R, T, and B-based bonded magnet with excellent magnetic properties. The discovery that this can be realized led to the present invention.

That is, according to the present invention, the powder obtained from the liquid quenched alloy has a sharp pulverized particle size distribution because it has high pulverizability.
Moreover, a raw material powder with a low oxygen content can be obtained, and since this powder is solidified from a liquid phase, the ratio of the amount of nuclei that becomes a liquid phase during heat treatment is high. Therefore, the powder and solid phase obtained by liquid quenching alloy are R2Fe, 4B
By mixing and molding the powder obtained from inkotsuto, which has a phase as a product, it is possible to uniformly disperse the nuclei that become the liquid phase during heat treatment, and it is possible to improve the squareness and coercive force of demagnetization characteristics. This makes it possible to obtain excellent magnetic properties.

To further explain the present invention in detail, R2Fe, which is a solid phase,
A homogenization heat treatment is performed on an ingot containing phase 14B as a main component,
Coarsely grind and finely grind to obtain powder.

A liquid quenched alloy is obtained from an R-rich alloy, finely pulverized, mixed with alloy powder containing the R2Fe and 4B phases as main components, and subjected to magnetic field compaction to obtain a compact.

This molded body is heat-treated to develop magnetic properties.

Next, this molded body is impregnated with resin and cured to form a bonded magnet.

Here, the liquid quenched alloy in the present invention refers to a powder or ribbon containing amorphous or microcrystals obtained by liquid quenching, and the amorphous alloy may be in the form of a ribbon or powder, and furthermore, when it is made into an amorphous ribbon, The manufacturing conditions are also simple because the ribbon may have defects such as scratches and holes.

In the present invention, the rare earth element R composition value of the powder containing the liquid quenched alloy is set to 40 νt% or more because alloys with a lower R composition are obtained from the liquid quenched alloy powder or ribbon (amorphous and microcrystalline) during heat treatment. This is because the amount of solid phase precipitated from the powder is too large, resulting in poor orientation and deterioration of properties.

In addition, the amount of powder obtained from the liquid quenched alloy is set to 0 to 70.
The reason for setting it as vol% (not including 0) is that in a region exceeding 70 vol%, there is too little solid phase powder, and the decrease in Br due to the decrease in the effect of magnetic field orientation during molding becomes significant.

[Example] The present invention will be explained in more detail below using Examples.

(Example 1) Using Nd, Fe, and B with a purity of 95 vt% or more, the Nd composition was 23.25.2 by high-frequency heating in an argon atmosphere.
7,29vt% (B is 2 types of 1.0.1.2wt%,
An ingot was obtained having the following properties: Febal).

Next, in order to reduce the α-Fe phase in these ingots, the ingots were held at 1000 to 1100° C. for 5 hours (in Ar) and then water quenched. These ingots were then coarsely ground. These eight types of coarse powder were used as I material.

Next, using the same Nd, Fe, and B as above, 4ONd-L, OB, and 54N were prepared using a single roll method in an argon atmosphere.
d-0,8B, 65Nd-0,6B.

74Nd-0,8B, 8ONd-0,3B, 87Nd-
An amorphous ribbon having a composition of 0,2B, 92Nd-0,1B, 100Nd (all Febal, vt%) was obtained. These amorphous ribbons were crushed. Eight types of coarse powders obtained from these amorphous ribbons were used as material (2). The powder of the material (2) obtained from these amorphous ribbons has a blending ratio of 8 vol%, with the remainder being 92 vol%.
vo%% is 31Nd- selected from I materials and mixed with the compound composition.
Nine types of coarse powders having L, OB-Febal (wt%) were obtained. Next, these coarse powders were pulverized to an average particle size of 3 to 5 microns using a ball mill. For comparison, 31Nd-1, OB-Febal was prepared in the same manner as above.
(vt%) was obtained and coarsely ground.

These powders were compacted at a pressure of 1.0 t/c- in a magnetic field of 10 kOe.

These compacts were heat treated in Ar at 800° C. for 2 hours.

These green compacts were impregnated with a resin-modified acrylate resin for impregnation, and heated at 130° C. for 2 hours to harden the resin and form bonded magnets.

FIG. 1 shows the magnetic properties of bonded magnets obtained by changing the composition of the amorphous powder used. Also, Comparative Example 31
The magnetic properties of a bonded magnet obtained from a type of Nd-0,1B-Febal (wt%) ingot were also described. Nd
The bonded magnet obtained by mixing amorphous alloy powder with a composition of 40 to 100 vt% has improved magnetic properties.

(Example 2) The powder obtained from the amorphous ribbon of material I obtained in Example 1 and the powder of material I obtained in Example 1 were mixed,
A powder having 31Nd-1, OB-Febal (vt%) was obtained. Next, this mixed powder was treated in the same manner as in Example 1 to obtain a green compact. These green compacts were heated to 800℃ for 2 hours.
Heat treated in r.

These green compacts were impregnated with a resin-modified acrylate resin for impregnation, and heated at 130° C. for 2 hours to harden the resin and form bonded magnets.

FIGS. 2(a), (b), and (c) show the magnetic characteristics of bonded magnets obtained by varying the mixing amount. Here the mixing amount is 0v
ol% is 31Nd-1 of the comparative example obtained in Example-1,
A bonded magnet obtained from an ingot of OB-Febal (wt%) is shown.

The amount of powder obtained from the amorphous ribbon is 0 to 7.
Improvement in magnetic properties is observed between 0 vol % (not including 0).

As shown in the above examples, in the production of Nd2Fe, 4B bonded magnets, a powder obtained by pulverizing an ingot mainly composed of Nd2Fe, 4B solid phase components has a higher concentration of Nd than this powder.
After obtaining raw material powder from an amorphous alloy that has a high value and becomes a liquid phase during heat treatment, these powders are mixed and formed into a compact, which is then heat treated and impregnated with an impregnating resin to form a bonded magnet.

Significant improvements in magnetic properties can be achieved.

Although only Nd2Fe and 4B bonded magnets have been described above, it can be easily inferred that similar effects can be expected for rare earth metal (R)/Fe/B bonded magnets including Y.

[Effects of the Invention] As explained above, according to the present invention, it is possible to produce an R2T14B bonded magnet having excellent magnetic properties, which is extremely useful industrially.

[Brief explanation of drawings]

Figures 1 (a), (b), and (C) are diagrams showing the relationship between the Nd composition value of the alloy powder (■ material) obtained from the amorphous ribbon and each magnet property for the bonded magnet in Example 1 of the present invention. , FIG. 2(a). (b) and (C) are diagrams showing the relationship between the mixing volume ratio of the alloy powder (■ material) obtained from the amorphous ribbon of the bonded magnet body and the magnetic properties in Example 2 of the present invention.

Claims (1)

[Claims] 1. R, Fe, B (where R is a rare earth element containing Y, T
In the method for producing a bonded magnet, the magnetic powder is compression-molded, heat-treated, and impregnated with a resin. Powder made from alloy is 0-70v
A method for manufacturing a bonded magnet, characterized in that the remainder of the ol% is a mixed powder consisting of R_2T_1_4B alloy powder.