JPS63111155A - Production of permanent magnet material - Google Patents

Abstract

PURPOSE:To obtain an Nd-Fe-B permanent magnet material having excellent magnetic characteristics by packing the powder formed by pulverizing a thin strip obtd. by quick cooling and solidifying of an Nd-Fe-B alloy into a hermetic vessel, then making the packed material anisotropic by plastic deformation. CONSTITUTION:The thin strip prepd. by melting the Nd-Fe-B alloy expressed by the formula in an inert atmosphere, then cooling the melt by an ultra-quick cooling method is pulverized by; for example, a ball mill, etc. in accordance with the conventional practice. The fine powder obtd. in such a manner is packed into the hermetic vessel which is so constructed that an inert gaseous atmosphere or vacuum can be maintained. The powder may be preliminarily press-formed to a prescribed shape at a room temp. and may be formed in the state of the higher density in the case of packing the powder into the vessel. The powder or molding packed into the hermetic vessel is then subjected to the plastic deformation treatment by a method such as; for example, unidirectional pressing or rolling and is thereby made anisotropic. The plastic deformation is preferably so executed as to attain >=30% rate of deformation. The desired Nd-Fe-B permanent magnet material is obtd. by the above-mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing an anisotropic Nd-Fe-B permanent magnet material.

Conventional technology Permanent magnetic materials are used in a wide range of fields, from general household electrical appliances to precision equipment and automobile parts.As electronic devices become smaller and more efficient, demands for improved magnetic properties are increasing. It is becoming more and more sought after.

Various proposals have also been made regarding Nd-FeB-based magnet materials. For example, a thin strip is produced by rapidly solidifying an Nd-Fe-B-based alloy, which is pulverized to a particle size of about 250μ, and the resulting powder is Methods of producing magnetic materials by compression molding are known. In addition, the thin ribbon obtained by rapidly solidifying the Nd-Fe-8 alloy is crushed, the obtained powder is hot pressed at a temperature of about 700'C, and then heated to plastically deform it to form an anisotropic magnet. Methods of manufacturing the materials are also known.

Problems to be Solved by the Invention However, with the former method, an anisotropic permanent magnet material cannot be obtained even if compression molding is performed in a magnetic field. In addition, in the latter method, when performing plastic deformation, the surface of the fine alloy powder is oxidized, causing a decrease in magnetic properties, especially coercive force, and also causing chipping of the molded product formed by hot pressing during plastic deformation. , or it may collapse.

The present invention has been made in view of the above-mentioned drawbacks in the prior art.

Means for Solving the Problems The present invention relates to a method for manufacturing an anisotropic Nd-Fe-B permanent magnet material, which is obtained by rapidly solidifying an Nd-Fe-B alloy. After crushing the ribbon and press-molding the obtained powder at room temperature if desired, filling it into a container,
It is characterized by sealing the container and plastically deforming the filling inside the container to make it anisotropic.

The present invention will be explained in detail below.

The Nd-FeB alloy used in the present invention is, for example, one represented by the following general formula.

NdxByFel X y (wherein, 0.05≦X≦0.30.0.01≦y≦0.
10 (molar ratio) In the above general formula, Nd may be partially substituted with another rare earth element, and B may be partially substituted with c,
It may be substituted with one or more elements selected from N, s;, p, and A1. Also, Fe is 20
Co, Mn, Ni, Ti, Zr, Hf,
■, 1 selected from Nb, Cr, Ta, MOL and W
It may be substituted by one or more elements.

In the present invention, the alloy components having the above composition are melted in an inert atmosphere, formed into a ribbon by ultra-quenching, and the resulting ribbon is pulverized by a conventional method such as a ball mill. Next, the obtained powder is filled into a container, which is made of iron, for example. The filled container is hermetically sealed, but the inside of the hermetically sealed container must be maintained in an inert gas atmosphere or vacuum, especially in a vacuum, e.g.
X 10-2mmH! It is desirable to create a vacuum of about 7. As the inert gas, argon, neon, helium, nitrogen, etc. can be used, but even in that case, it is preferable to maintain the pressure in a reduced pressure state.

When filling a container with powder, the powder should be press-formed into a predetermined shape at room temperature to make it denser in order to make it easier to handle and improve the magnetic properties of the final product by increasing its density. You can leave it as is.

The powder or molded product filled in the container and sealed is then subjected to plastic deformation treatment to be made anisotropic. Plastic deformation can be achieved, for example, by unidirectional pressing, rolling, swaging,
This is done using methods such as forging.

The plastic deformation is preferably performed so that the deformation ff is 130% or more. This is because if the amount of deformation is lower than 30%, sufficient magnetic properties cannot be obtained.

Function The present invention involves pulverizing a ribbon obtained by rapidly solidifying an Nd-Fe-B alloy, press-forming the obtained powder at room temperature if desired, filling it into a container, and sealing the container. Since the filling in the container is plastically deformed, the surface of the powder obtained by pulverization is made anisotropic without being oxidized. Therefore, the obtained Nd-Fe-B based magnet material has excellent magnetic properties.

Example Hereinafter, the present invention will be explained by examples.

Example 1 An alloy having a composition of 29% Nd, 81% Nd, and the balance Fe was melted in a melting furnace to obtain an ingot. This ingot was melted and blown with argon onto a single roll rotating at a peripheral speed of 20 m/sec to form a thin ribbon, and the obtained ribbon was ground with a ball mill until the particle size was 200 μm or less. The obtained powder was press-molded into a predetermined shape at a pressure of 7 t/cn at air temperature, and the obtained molded product was vacuum-sealed in a carbon steel container at a vacuum degree of 1×10 −2 mmHg. This carbon steel container was compressed by a press at the temperature listed in Table 1 to a deformation amount of 50%, and was plastically deformed to make it anisotropic. A magnetic property test piece was cut out from the obtained magnet material and its magnetic properties were measured. The results were as shown in Table 1. In the following, 3r represents the residual magnetic flux density, B@c Lt coercive force, and (BH)maX the maximum energy product.

As is clear from Table 1, the magnetic properties are excellent when the plastic deformation temperature is 100 to 900'C, and particularly excellent results were obtained at 400 to 700'C.

Example 2 A magnet material was produced by the same treatment as in Example 1,
The magnetic properties were measured. However, plastic deformation at a temperature of 600
'C, the deformation amount was as shown in Table 2. The results were as shown in Table 2.

Table 2 - □ As is clear from Table 2, when the amount of deformation during plastic deformation was 30% or more, the magnetic properties became excellent.

Effects of the Invention By having the above-described structure, the present invention can easily produce an anisotropic magnet from a thin ribbon produced by rapid solidification of an Nd-Fe-B alloy, which has traditionally been difficult to produce, without applying a magnetic field. Several families of anisotropic magnets can be manufactured. The anisotropy can be achieved by filling a container with the powder obtained by crushing the ribbon and sealing the container, so that the anisotropy can be achieved without oxidizing the surface of the powder particles. N
d-Fe-8 based magnet materials have excellent magnetic properties.

Claims (5)

[Claims] (1) The thin strip obtained by rapidly solidifying the Nd-Fe-B alloy is pulverized, the obtained powder is press-molded at room temperature if desired, and then filled into a container, the container is sealed, and the A method for producing a permanent magnet material, the method comprising plastically deforming a filling therein to make it anisotropic. (2) The method for producing a permanent magnet material according to claim 1, wherein the plastic deformation is performed at a temperature of 100°C to 900°C. (3) The method for producing a permanent magnet material according to claim 1, wherein the plastic deformation is performed at a temperature of 400°C to 700°C. (4) The method for manufacturing a permanent magnet material according to claim 1, wherein the plastic deformation is performed to a deformation amount of 30% or more. (5) A method for producing a permanent magnet material according to claim 1, characterized in that the powder obtained by pulverizing the ribbon is press-molded at room temperature to increase the density, and then filled into a container. .