JPS60194502A - Preparation of permanent magnet blank - Google Patents

Abstract

PURPOSE:To improve characteristics peculiar to a permanent magnet by bringing a rare earth metal R, a transition metal T and a R-T-S alloy as a submetal or a semiconductor S to an amorphous state and thermally treating them in a magnetic field. CONSTITUTION:An alloy having a composition such as one represented by Table I is melted by using an induction furnace and an ingot is obtained and employed as a hardener, and a permanent magnet blank is prepared through an ultra-quenching method by one-sided roll in an Ar gas atmosphere at fixed gas pressure by using an amorphous thin-band forming device. The blank is thermally treated in argon gas for 0.5-3hr at an optimum temperature between 500- 900 deg.C as it is left as it is prepared through the quenching method. Accordingly, a magnet having high performance is acquired by a blank, cost thereof is low.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a method for producing rare earth permanent magnets [Prior Art] Conventionally, rare earth magnet alloys have been produced by a general method of melting in a normal crucible and then casting into a mold. It had been. Alloys made with this method have a regular crystal structure. On the other hand, it has recently been discovered that an amorphous alloy, which does not have a crystalline structure and is obtained by ultra-quenching molten metal, has a high coercive force. These alloy systems include
Na-Fe, Pr-Fe, Tb-Fe, F
Alloys such as e-B-La-4b have been reported (e.g. J, J, Croat:, T, Appl, Phys
, Vol. 53° (1981), 5161). Because this amorphous permanent magnet can utilize a metastable phase that is not an equilibrium phase, many excellent properties have been discovered that were not found in the past. In addition, by promoting heat treatment, the state of the metastable phase can be easily controlled and the properties can also be improved. However, permanent magnets made of these alloys are isotropic magnets, and their energy product is at most 6~
There was a problem in that it had a value of about 8MGOe, which was considerably lower than current rare earth cobalt magnets.

〔the purpose〕

The present invention is intended to solve these problems, and its purpose is to increase the saturation magnetization and coercive force of the rare earth amorphous permanent magnet as described above, and further improve the squareness of the hysteresis curve. It is possible to improve the maximum energy product.

[Summary] The present invention achieves an amorphous state of an RT-S alloy of rare earth metals, R, transition metals, and semimetals or semiconductors by some method, and heat-treats it in a magnetic field to change the arrangement of atoms. It is characterized by improving the unique characteristics of permanent magnets by arranging taro in an unconventional way.

〔Example〕

Hereinafter, the present invention will be explained in detail based on examples.

Example 1 An alloy having the composition shown in Table 1 was melted in an induction furnace to obtain an ingot. These were used as the mother alloy.

Table 1 This alloy contains rare earth elements and is therefore susceptible to acid oxidation. Therefore, using an amorphous ribbon producing apparatus capable of controlling the gas atmosphere at 1/1, it was produced by an ultra-quenching method using a single roll method in an Ar gas atmosphere at a constant gas pressure. The roll is made of copper (diameter 240 mm) and has a rotation speed of 3600 to 480.0.
They were 1e, p, and m. The prepared sample has a width of 1 to 2 ta
% thickness is about 20 to 30 μm.

The obtained sample was prepared by the rapid cooling method and the temperature was 0500-9.
After heat treatment in argon gas for 0.5 to 5 hours at an optimal temperature between 00℃ or alternatively after heat treatment in a magnetic field using the optimal heat treatment conditions obtained in step 1 in a magnetic field of 15000e. 3 conditions using a vibrating sample magnetic measuring machine (VSM)
) was used to investigate magnetic performance. The results obtained are shown in Figure 1. It can be seen that the coercive force iHI is significantly improved by heat treatment and further by heat treatment in a magnetic field.

Example 2 The alloy composition is OeQ, 6NdO, 2PrO, 2(?eG
, 94130,06n6.0 was melted using an induction furnace, and a quenched ribbon was produced from this master alloy in the same manner as in Example 1. 3KO
Heat treatment was performed at 800° C. for 3 hours while applying a magnetic field of e.

The magnetic performance of the obtained sample at room temperature was examined by VSM. The results are shown in Figure 2. The coercive force iHc begins to rise when the magnetic field strength exceeds 0.5 K Oθ, and the saturation magnetization is 162 to 2. Q
]11m013 was the best value for & in this case. Overall, it is clear that the magnetic performance is greatly improved by magnetic field heat treatment.

Example 6 0eO, 05NdO, 2PrO, 2LaO, 05(Fe
d, 92 Bo, 06 Si0.01! At0.01)
6. Conducting an amorphous ribbon of an alloy with a composition of 1
It was made in the same way as. This ribbon was subjected to the same six conditions as in Example 1 (i.e., ■ to )) G, and the B-H curve was measured. The measured values are shown in Figure 3. The maximum energy product was 7.3 MGOe when producing the thin ribbon (■), IMGOe, and 7.3 MGOe during the heat treatment (■), which was significantly improved by the heat treatment in the magnetic field.

Example 4 The alloy ribbon obtained by heat treatment in a magnetic field in Example 3 was pulverized into powder, which was bonded with a resin interlayer.
A resin bonded magnet was manufactured. Molding method (1) Powder molding (11) Injection molding was performed. (b) The alignment molding was performed in a magnetic field of about 15KO6. The manufacturing conditions are shown in Table 2. The performance of the obtained magnet is shown in Table 6.

Table 2 [Effects] As described above, according to the present invention, it has been found that by heat-treating the ribbon obtained by rapid cooling in a magnetic field, it is possible to produce a magnet with unprecedented high performance. Not only does it have the effect of improving performance, but it also has the effect of lowering the cost of magnets, since considerable properties can be obtained with inexpensive raw materials, and it plays a role in industry.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the effects of heat treatment Un in a magnetic field on alloys of various compositions. FIG. 2 is a diagram showing the relationship between magnetic field strength and magnetic performance in magnetic field heat treatment. Figure 3 shows how much B-H is produced by heat treatment in a magnetic field according to the present invention.
It is a figure which shows whether a curve was improved. ■・・・No treatment■・・・Heat treatment■・・・・・・Heat treatment in magnetic field or more (RρC) Chest 2, Figure 3

Claims (1)

[Claims] In the alloy R-T-8 of a rare earth metal (hereinafter denoted by R), a transition metal (hereinafter denoted by T), and a semimetal or semiconductor element (hereinafter denoted by S), an amorphous alloy is produced by an ultra-quenching method, and then A method for producing a permanent magnet, which comprises heat-treating the alloy in a magnetic field.