JPS59177346A - Alloy of rare earth metal for magnet material - Google Patents

Abstract

PURPOSE:To reduce the effect of impurities contained in a rare earth metal and to improve the magnetic characterustucs by adding prescribed percentages of Fe, Co and B. CONSTITUTION:The titled alloy consists of, by weight, 3-20% in total of 3- 20% Fe and/or 2-33% Co and the balance rare earth metal or further contains <=10% B. The effect of impurities contained in the rare earth metal is reduced, and the magnetic characteristics are considerably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides Fe-B-R system, Fe-Co-B-R system (
R is a rare earth element containing Y) Permanent magnets, especially Fe-B-Nd system with excellent magnetic properties, Fe-Co-El-,
The present invention relates to a material alloy used for Nd-based permanent magnets, and relates to a rare earth alloy that contains few impurities that degrade the magnetic properties of the final product.

Permanent magnetic materials are extremely important electrical and electronic materials used in a wide range of fields, from various household appliances to peripheral terminals for large Combi Utah. In recent years, with the demand for smaller size and higher efficiency of electrical and electronic equipment, permanent magnet materials are required to have increasingly higher performance.

Current typical permanent magnet materials are alnico, hard ferrite, and rare earth cobalt magnets.

As the raw material situation for cobalt has become unstable in recent years, demand for alnico magnets containing 20 to 30 wt% cobalt has decreased.
Inexpensive hard ferrite, whose main component is iron oxide, has come to dominate magnet materials.

On the other hand, rare earth cobalt magnets contain 50 to 60wt of cobalt.
% and S, which is not contained in rare earth ores very much.
Although it is very expensive because it uses Wl, it has much higher magnetic properties than other magnets, so it has come to be used mainly in small, high-value-added magnetic circuits.

Therefore, the present inventor previously proposed an Fa-8-R-based (R is a rare earth element containing Y) permanent magnet as a new high-performance permanent magnet that does not contain expensive Sm (Patent Application No. 57-1).
No. 45072). Furthermore, in order to improve the n1 coordination characteristics of the permanent magnet made of the magnetically anisotropic sintered body of the Fe-B-R system, by substituting and covering a part of Fe with 6, F with improved temperature characteristics by raising the temperature by one point.
A permanent magnet made of e-Co-El-R optically anisotropic sintered body was proposed (Japanese Patent Application No. 166663/1982). The novel permanent magnet described above is manufactured by the following steps.

(1) As a starting material, electrolytic iron with a purity of 99.9%, 81
A ferroboron alloy containing 9.4% with impurities such as Fe and /V, SL, and C, a rare earth metal with a purity of 99.7% or more, or an electrolytic material with a purity of 99.9% is melted by high frequency. , then water-cooled copper casting, (2) coarsely pulverized with a stamp mill to 35 mesh through, then pulverized with a ball mill for 3 hours (3 to 10 μm), oriented in (31!L field (10KOe)), molded (1.5t
(4) Sintering, 1000°C to 1200°C, 1 hour, Ar
Medium, left to cool after sintering.

Rare earth metals as starting materials for producing the above-mentioned Fe-B-R series and Fe-Co-8R series (R is a rare earth element containing Y) permanent magnets are generally produced by a Ca reduction method or an electrolytic method.

In general, rare earth metals produced by the Ca reduction method, for example, in the case of ceramics, are separated and purified by the reaction of the following formula (1).

FeCa2 2mF3 + 3Ca-1 → 2M+ 3Ca F2・
...(1) However, due to the high viscosity of the molten metal, it is difficult to separate the ceramic from CaF2 and CaCR2, and Cat''2 and Ca(J2) may be mixed into M, or the furnace material, NdF3 , 02, an impurity in Ca C12, becomes a solid solution with ceramics and becomes an M2O3 product and exists in M. Furthermore, since the melting point of ceramics is as high as 1050℃, 1200℃~1
When heated and reduced to 300° C., it reacts with the furnace material of the reactor, resulting in a decrease in purity, which has a negative effect on the magnetic properties of the produced magnetic alloy.

In addition, when manufacturing by electrolytic method, the melting point of the ceramic is 1050
℃, it was necessary to raise the temperature of the molten metal and the salt bath to about 1200℃, which caused various problems such as the unavoidable contamination of impurities from furnace refractories, fluorides, etc.

This invention is based on Fe-Et-R system, Fe-Co-BR system (
(R is a rare earth element containing Y) In view of the fact that the purity of the rare earth metal that is the starting material in a permanent magnet does not affect the magnetic properties of the magnet alloy and has a significant effect, we aim for a rare earth metal for the raw material of the magnet alloy with high purity. The aim is to create a blended alloy that allows rare earth metals to be used in highly pure form when melting magnetic alloy materials.

That is, in this invention, Fe5wt% to 20wt%.

A rare earth material for a magnet material containing one or two of C02 wt% to 33 wt%, but when two types are contained, the total amount is 3 wt% to 20 wt%, and the remainder is substantially composed of rare earth metals. alloy, and further, the above rare earth alloy, B
The main point is that it contains 10wt% or less of i There are rare earth alloys for magnet materials.

This invention is capable of lowering the melting point of the ceramic, the viscosity of the molten metal, and the temperature of the molten metal by adding and melting Fe, Co, and B, which are the basic components of the magnet, during Ca reduction to obtain rare earth metals. Less XFe alloy, ゛・tk
As Fe13 alloy, M6 alloy, NdFeCoB alloy,
This is based on the knowledge that 1q of extremely excellent alloys can be used as blended alloys when melting magnet materials.

To be more specific, as shown in Figures 1 and 2, which show the changes in the melting point of ceramics due to the addition of Fe or
The melting point of ceramic, 1050°C, decreases with the addition of e, and when 10% is added, a eutectic structure is formed and the melting point is the lowest at 710°C, and as the amount of addition increases, the melting point rises again.
It can be seen that when F is added, the melting point decreases as the amount added increases, and when F is added at 20%, a eutectic structure develops and the melting point reaches 600° C., and when further addition is made, the melting point becomes TR again.

To be more specific, RF3 or R2O3 is Ca
When reducing, RF3 or R2O3 is mixed with Ca as a flux in an alumina crucible.
Fe,
When Co and B are added and melted, if 1< is ceramic, the following reactions (2), (3), and (4) will lower the melting point of the ceramic, the viscosity, and temperature of the molten metal, resulting in t' with less impurities. ! :lFe
Alloy, tJdFeE1 alloy, tVkICo alloy, tUF
ecoB alloy 19.

CaCI2NaF3+Ca+Fe--→FeNd+CaF2
--f2) CaC evening 2 1? F 3+ Ca + Co −-→CohJ
10Ca F 2 -- (31CaC 2 m F 3 +Ca 10Fe 4- Fe s B 6
−-→Fe [3Nd + Ca F2...
- (4) Although the case using the Ca 3% i primary method has been described above, the rare earth alloy for magnet material can be manufactured by the molten salt electrolysis method.

In the case of molten salt electrolysis, mFe alloy can be produced by the following steps. A mixed salt of neodymium fluoride, barium fluoride and rhidium fluoride was used as the electrolytic bath, and neodymium oxide was used as the raw material. The electrolytic cell was made of graphite and boron nitride sintered body, the anode was made of graphite, and the cathode was made of iron plate.

When electrolyzed at 950° C., the ceramic deposited on the cathode iron plate reacts with iron to form a low melting point Nci-Fe alloy, which settles at the bottom of the electrolytic cell, allowing continuous production. In addition, when manufacturing an NdcO alloy, it is preferable to use 6 for the cathode. Also,
Mix Fe oxide, B oxide, and 00M compound in a salt bath,
Even by ordinary rare earth electrolytic refining, mFe, 1Nul
Alloys such as BFe, IUco, etc. can be obtained.

Next, the reason for limiting the composition of the rare earth alloy for magnet material according to the present invention will be explained.

If the Fe content is less than 3 wt% and more than 20 wt%,
The melting point of the ceramic is over 1000℃, and the resulting alloy contains
CaF 2 and CaC:R2 may be mixed in, or the impurity 02 in the furnace material, NiF 3 and CaCj2 may become a solid solution with the moiety and exist in M as a moiety 203 product.
The content is preferably in the range of 3 wt% to 20 wt%, since the purity of the ceramic will be lowered and the magnetic properties of the magnet alloy made from it will be deteriorated.

If the CO content is less than 2 wt% and more than 33 wt%,
In the case of 28% B, 50% or less, and the balance Fe, it exhibits magnetic properties equivalent to the above magnet alloy, and the temperature coefficient of residual magnetic flux density is 0.1%/° C. or less, which is the same as that of the magnetic alloy.

In addition, a magnetic anisotropic magnet alloy in which the main component of R, that is, 50 atomic % or more is a light rare earth metal, has a composition (atomic %) of 1
In the case of 2% to 20% R, 4% to 24% B1 balance Fθ or further 5% to 45% Coff1 right, the magnetic properties are the most irregular, and especially light rare earth metals are used for ceramic sharpening (B
l-1) The maximum value of max reaches 33 MGOe or more.

Furthermore, Fo-BR system, Fe-Co-EI R system 1
(It is possible to avoid containing at least one of the following additive elements M in the stone alloy. In addition, when two or more kinds are added, the content shall be below the maximum value of the additive element M.

TL 4.5% or more -1・, NL 4.5% or less, B
j 5% or less, ■ 9.5% or more, Nb 12
．． 5% or less, Ta 10.5% or less, Cr 8.
5% or less, MO9.5% or less, W 9.5% or less, Mn
3.5% or less, N9.5% or less, Sb 2.5%
Below, C @ 7% or less, Sl 3.5% or less, Zy
5.5% or less, He 5.5% or less. Examples according to the present invention will be shown below to clarify its effects.

Example 1 1VkIF3 powder, Fe powder, and Ca powder were fluxed in an alumina crucible and heated and melted at 1070°C in an argon gas atmosphere using CaCR2 to produce 4.1w.
A t% FθM alloy was obtained.

The amount of impurities contained in the 1:1 4,1 wt% FeNe1 alloy is shown in Table 1 together with the amount of impurities contained in commercially available ceramic metals. As is clear from the results, it can be seen that the amount of impurities is significantly reduced.

Next, as a starting material, the above 4.1 wt% Fe! l
I alloy, 99.9% pure electrolytic iron, El 19.4%
10 boron alloy (containing ) was high-frequency melted and then cast in a water-cooled copper mold to produce an ingot of 1-.

This ingot was coarsely pulverized with a crushing stamp mill to a throughput of 35 meshes, and then pulverized with a ball mill for 3 hours to form a fine powder with a particle size of 3 to 1101I. After being oriented in the Tsui-C,ru field (10KOo), it was pressure-molded at 1,514 to obtain a molded body with a length of 15 mm and a width of 5 m and a width of 10 mm.

The obtained molded body was sintered at 1100° C. for 1 hour under sintering conditions in Ar, and after sintering, it was allowed to cool to form a -C magnet alloy of 1η.

The composition of the magnet alloy at this time is 15% Nd, 8
%B, with 77% Fe, coercive force HCl0KOe, 95
It exhibited magnetic properties with a residual magnetic flux density of 3r 12.5 KG, and a maximum energy product (BH) max of 35 MGOor.

For comparison, commercially available ceramics containing poly-impurities as shown in Table 1 were used as the starting material ceramics, but the same composition was produced under exactly the same manufacturing conditions in atomic % of 15% M, 8% B, 7
The comparative magnet alloy of 7% Fe has a coercive force Hc of 10KOe,
Residual magnetic flux density Dr 12. Indicates the magnetic properties of IKG,
Maximum energy product (81-1) max is 31M G O
It can be seen that by using the rare earth alloy for magnet materials according to the present invention, the influence of impurities contained in the rare earth metal is small and the magnetic properties are greatly improved.

Example 2 KF3 powder, ferroboron powder, Fe powder, Ca II
) powder as a flux in an alumina crucible.
12 and heated and melted at 1020° C. in an argon gas atmosphere to obtain a 17 wt % Fe 2 wt % BX alloy.

The amount of impurities contained in the obtained 17wt%Fe2wt%BM alloy is shown in Table 1 together with the amount of impurities contained in commercially available ceramic metals. As is clear from the results, it can be seen that the amount of impurities is significantly reduced.

Next, as a starting material, the above 17wt%Fe2wt%
BNd alloy, 99.9% pure electrolytic iron, El 19.
A ferroboron alloy containing 4% was high-frequency melted, and then cast in a water-cooled copper mold to produce an ingot of 1-.

This ingot was coarsely pulverized by a crushing stamp mill to a throughput of 35 meshes, and then pulverized by a ball mill for 3 hours to form a fine powder with a particle size of 3 to 10 um. Then, the magnetic field (10
After orientation in KOe), pressure molding was performed at i, st, and g to obtain a molded product measuring 15 mm x 15 mm x 1001 m.

The obtained compact was sintered at 1100° C. for 1 hour under sintering conditions in Ar, and after sintering, it was allowed to cool to obtain a magnet alloy.

The composition of the magnetic 6 alloy at this time is 15% M, 8% in atomic percent.
B, 77% Fe, coercive force) 1c 15.5KOe
Except for using commercially available ceramics containing A-impurities, 15 atomic% and TC0% ceramics with the same composition made under the same manufacturing conditions as those produced under the same manufacturing conditions, 8
% B, 20% θ, 57% e, coercive force Hc 9 K Oe, residual magnetic flux density [31' 11.
It exhibits magnetic properties of 5K G, and the maximum energy product (B
H) max is 30MGOQ, and by using the rare earth alloy for magnet material according to this invention, the influence of impurities contained in rare earth metals is small, and the magnetic properties are greatly improved.
It turns out that 2J.

Example 4 Using a mixed salt bath of Nsj F 3 , Ba F 2 , and L+F, an MFe alloy was prepared by an electrolytic method using 'Cm203 as a raw material. The side walls of the bathtub were made of graphite, the bottom surface was made of BN sintered body, the anode was made of graphite, and the cathode was made of iron plate. Electrolysis was performed by heating the salt bath to 950°C, and 10.2wt%F
eNj containing 1 piece.

Table 1 shows the amount of impurities contained in the obtained 10.2 wt% FeNd alloy. KI with high purity even when using electrolytic method
Fe alloy can be obtained and this alloy can be used to produce mFe
B When a permanent magnet is made, conventional commercially available pure ceramics are folded into a shape with magnetic properties.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the change in melting point when Fa is added to ceramics, and FIG. 2 is a graph showing changes in melting point when chives are added to ceramics. Applicant Sumitomo Special Metals Co., Ltd. Agent 1) Hisashi Yoshi1;,j Figure 1 Figure 2 Co (wt%) Continued from page 1 [Phase] Inventor Atsushi Hamamura Egawa, Shimahon-cho, Mishima-gun, Osaka Prefecture 2-15-17 Sumitomo Special Metals Co., Ltd. Yamazaki Works

Claims (1)

[Claims] I Fe5wt%~20wt, C;o 2wt%~
Rare earth alloy 2 for magnet materials characterized by containing 33 wt% of one or two types, but the total amount of the two types being 3 wt% to 20 wt%, and the remainder substantially consisting of rare earth metals. e3wt%~20Wt, Co 2wt%~3
3wt% of one or two types, but when two types are included, the total amount is 3wt% to 20wt%, and further 10w of B.
A rare earth alloy for magnet materials, characterized in that it contains t% or less, and the remainder consists essentially of rare earth metals.