JPS62181402A - R-b-fe sintered magnet and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve a coercive force and to improve magnetic characteristics, by adding at least one kind of carbides of specified amounts of Nb, Ti, Zr and Hf in R-B-Fe alloy powder or mixed powder comprising the same composition. CONSTITUTION:R-B-Fe alloy powder, in which R (R is at least one kind of rare earth elements including Y), B and Fe are essential components, or mixed powder comprising the same composition is prepared. As at least part of the alloy powder, mixed powder, in which one or more kinds of transition metal powder representing Fe, B-transition metal alloy powder, R-transition alloy powder and the like are replaced, can be used. In said powder, 0.05-3.5wt% carbide powder of Nb, Ti, Zr and Hf is compounded, and mixing molding, sintering and heat treatment are performed. Thus a material having a large coercive force (iHc) and excellent magnetic characteristics can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an R-B-Fe sintered magnet whose υ coercive force (iHc) is improved by adding carbide.

r # center technology] In recent years, compared to conventional Sm -Co magnets, Nd -B - which has higher magnetic properties and does not necessarily contain Sm or CO, which are expensive in terms of resources, has been developed. Fe-based permanent magnets were invented. (Sayo et al., J. Appl. Phys., 55 (6
).

15March 1984, p2083-2087
．． and Japanese Unexamined Patent Publication No. 59-46008, No. 59-20
(See Publication No. 4209) They disclose that the manufacturing method involves pulverizing an alloy ingot obtained by melting and casting, press-forming while applying a magnetic field as necessary, and further sintering. .

[Problem that the invention seeks to solve]

However, with these conventional manufacturing methods, it has not been possible to obtain a sufficiently satisfactory coercive force (iHc) in terms of magnetic properties.

The present invention solves the above-mentioned problems of the prior art and has a coercive force (
It is an object of the present invention to provide a manufacturing method capable of obtaining an R-B-Fe-based sintered magnet with a large iHc) and excellent magnetic properties.

[Failure to solve the problem]

That is, the present invention provides an R-
B--Fe alloy powder or a mixed powder having the same composition is further mixed with carbides of Nbr Ti, Zr T Hf, ie, at least one of NbC, Tic, ZrC, and HfC at a weight percentage of 0.05 to 3. To explain the present invention in detail, first, R-B-Fe-based alloy powder having predetermined components is prepared by conventional means. For example, alloy powder is prepared by melting and casting an ingot into powder, by melting and totomizing it, or by a reduction diffusion method using a rare earth oxide as a starting material. Ru.

At least a part of the above alloy powder is a transition gold lump powder representing Fe, boron powder, rare earth metal powder, B-transition metal alloy powder, R-
Even if 1 ffl (received as a gift or a mixed powder of two or more) such as transition metal alloy powder is used as a substitute, the effects of the present invention will not be lost.

Carbide powders of Nb + Ti, Zr, and Hf are added to the above powder in an amount of 0.05 to 5.5 wt.

If it is less than 0.0, ass or exceeds 3.5%, the effect will be small, so it is set at 0.05 to 3.5 wt%.

The mixed powder obtained by the above method is molded and compacted using a compression press or the like.

In addition, the above molding-consolidation is performed at o, 5 to 1 o tA.
! The molding pressure is good, and the magnetic properties can be improved by applying a magnetic field (5 KOe or more) during molding if necessary. The series of molding and compaction may be performed wet or dry, and may be performed at a high temperature other than room temperature. The atmosphere is preferably a non-oxidizing atmosphere, and may be carried out, for example, in a vacuum, an inert gas, or a reducing gas. The obtained molded body is sintered at a temperature of 900 to 1200°C. Below 900°C, the density does not increase, so Br is sufficient and 1 (120
If the temperature exceeds 0° C., Br and squareness deteriorate. ○ Sintering is preferably performed in a non-oxidizing atmosphere to prevent oxidation of the R element. That is, a vacuum, an inert gas, or a reducing gas atmosphere is preferable. Note that the rate of temperature increase from room temperature during sintering is not particularly specified;
By maintaining the temperature in the temperature range of ~800°C for at least 0.5 hours, it becomes possible to improve the temperature uniformity of the heated part and to perform degassing treatment in a vacuum. Alternatively, cracking (hydrothermal cracking) of stearate used as a lubricant can also be carried out in a hydrogen gas atmosphere.

Therefore, the atmosphere for sintering is preferably a vacuum or a non-oxidizing atmosphere such as an inert gas (for example Ar) or a reducing gas (for example Hz).

The cooling rate after heating and holding is not particularly specified, but is 0.5~
100 minutes is good, and 1 to 10 minutes is generally good.

This is because by slowing down, variations in magnetic properties due to subsequent heat treatment are reduced. Also, cooling may be done once to room temperature, or to about 500℃,
Sintering and heat treatment may be performed continuously so that the temperature is raised again for the next heat treatment.

After the above sintering, in order to further improve the magnetic properties,
Aging treatment is performed at 00 to 700°C, but if necessary, holding and slow cooling can be improved at 800 to 1000°C before aging. Heat treatments such as aging treatment and intermediate heat treatment are the same as the sintering described above.
A non-oxidizing atmosphere is preferred.

The aging treatment may be carried out by holding at 500 to 700°C for at least 0.5 hours and then rapidly cooling. This is because if the temperature is less than 500°C, the effect will be small, and if it exceeds 700°C, the magnetic properties will deteriorate.

Next, to explain the reasons for limiting the components of the rare earth/poron/iron-based sintered magnet to which the present invention is applied, the magnet of the present invention includes the rare earth element R (where R is at least one rare earth element including Y), boron, and Iron is an essential element. To explain in more detail, R is neodymium (Nd), praseodymium (P
r) or mixtures thereof (didim), and also lanthanum (La).

Cerium (Ce), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Europium (Eu) + Samarium (S)
m), gadolinium (Gd), promethium (Pm)
), thulium (Tm), ytterbium (Yb)
, may contain rare earth elements such as lutetium (Lu) and yttrium (Y), and the total amount ψQ + χn is 100%.
- Q Hyakue Naode, Gomochi? It is not possible to obtain sufficient coercive force,
This is because when the number exceeds 60 atoms, the residual magnetic flux density decreases. Boron B has 2 to 28 atoms. This is because if it is less than 2 atoms, a sufficient coercive force cannot be obtained, and if it exceeds 28 atoms, the residual magnetic flux density decreases and excellent magnetic properties cannot be obtained. Fe is essential as an element other than R and B, and contains 940 to 90 atoms.

Below 40 atoms, the residual magnetic flux density (Br) decreases, and 9
This is because a high coercive force (iHc) cannot be obtained if it exceeds 0 atomic force.

Rare earth/boron/iron based sintered magnets can be created using the above R-B and Fe as essential elements, but as described below, even if some of the iron is replaced with other elements or even if impurities are included, the present invention will still work. The effect will not be lost.

That is, instead of Fe, up to 50 atoms of co.

It may be replaced with Ni having 8 atoms or less. This is because if Co exceeds 50 atoms, high iHc cannot be obtained, and if N1 exceeds 8 atoms, high Br cannot be obtained. In addition, as elements other than the above, one or more of the A elements other than the following specified atoms (however, if 2a! or more is included, the total amount of A elements
The effect of the present invention is not lost even if the element having the maximum value or less) is replaced with Fe element. Element A is shown below.

Next, examples of the present invention will be described, but the present invention is not limited to these examples □ [Example] Example 1 15.8Nd-8B-Remaining Fe (atomic %) was dissolved. , an alloy ingot was obtained. The alloy ingot was made into a fine powder with an average particle size of 6.3 μm using a di-1-crusher, a brown mill, and a jet mill, and TiC (average particle size 1.8 μm) was mixed with it as shown in Table 1.

The mixture was mixed to obtain raw material powder.

Table 1 The obtained raw material powder was placed in a magnetic field (10
KOe), and the obtained molded body was molded in vacuum (10-”T
After sintering at 1100° C. for 2 hours, the sample was cooled in a furnace, then heat treated again at 640° C. for 1 hour, and then rapidly cooled to evaluate magnetic properties. The results are shown in Table 1.

As shown in Table 1, compared to <Tic-free (A1),
It can be seen that by adding TIC (numbers 2 to 7), the coercive force (iHc) is significantly improved. However, TiC5
, 7% additive material (flat 7) causes a significant decrease in residual magnetic flux density (Br).

Example 2 As shown in Table 2, carbide powder (average particle size 1.6 to 2.0
μm), mixed, and molded in the same manner as in Example 1.

It was sintered and heat treated, and its magnetic properties were evaluated.

The results are shown in Table 2.

Table 2 As shown in Table 2, NbC addition (Y8, 9, 10).

11) also shows an improvement in coercive force, similar to TiC.

In addition, combined addition of NbC and ZrC (A 12.13.1
Similar results were observed for 4).

However, when the amount added is excessive (A11, A14), a significant decrease in Br occurs as in the case of flat plate 7.

〔Effect of the invention〕

Claims (1)

[Claims] 1. R-B-Fe alloy powder containing R (where R is at least one rare earth element including Y), B and Fe, or a mixed powder having the same composition. further N
R-B-Fe characterized by blending at least one of bC, TiC, ZrC, and HfC in an amount of 0.05 to 3.5% by weight, and performing mixing, molding, sintering, and heat treatment. A method for producing a sintered magnet. 2. At least one of NbC, TiC, ZrC, and HfC
An R-B-Fe sintered magnet characterized by containing 0.05 to 3.5% by weight of seeds.