JPS62241304A - Rare earth permanent magnet - Google Patents

Abstract

PURPOSE:To obtain a permanent magnet which assures excellent magnetic characteristics and wide range of application, even with reduced amount of expensive Co, by adding Zr or Hf of the predetermined amount to the R-Fe system magnetic material. CONSTITUTION:A rare earth permanent magnet can be obtained by melting, casting, milling, molding and sintering a composition consisting of at least one or more kinds of rare earth element R including Y of 12-45% in the weight percentage, the element M of 0.5-25%, Fe as the remainder or a combination of Fe and Co and impurity as the essential element. The element defined by R is the rare earth elements consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu adding Y. These elements are used individually or in combination of two or more kinds. Thereby, the rare earth permanent magnet is stabilized in the 3-element system compound phase through introduction of Zr, Hf, or both of them and the Curie point and saturated magnetization are improved. Thereby, high magnetic characteristic can be attained and a part of Zr or Hf can be replaced with Ti.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to rare earth permanent magnets with excellent magnetic properties useful as materials for various electrical and electronic devices.

(Prior Art and Problems) Samarium cobalt magnet SmCO5 is a rare earth magnet that is well known and has been mass-produced.

This magnetic property is the maximum energy product (B H)■a! is an experiment (over 20 MGOa in 1, 1B-1 even at the impurity level)
8MGOe, and is used as a high-performance magnet for speakers and other
Widely used in meters, measuring instruments, etc. However, this S
Since m-based magnets use more than 60% of expensive Co metal, it is desirable to replace Co with an inexpensive element such as Fe, and attempts have been made to do so.
C5 compounds have not been successful because they do not have a solid solubility limit for Fe.
Compounds of 2, RF e 3, and 12 Fe 1- are well known, but the Curie point Tc and saturation magnetization 4π
In R-Co compounds that are not magnetized because either M s or crystal magnetic anisotropy external constant aKu is low, CaC
There are RCo compounds with u5 type crystal structure, and 1i
Although it has been put into practical use as a 5mCO5 magnet as described in J.
Among Fe-based compounds, the existence of RF e s compounds has not been known so far. Therefore, for R-Fe binary compounds, the quenched ribbon method (IEEE Transact) of Craat et al.
ions on Magnetics, Vat, M
There is no example of A being magnetized other than the metastable phase due to 18°+442; Mav-LaB5).

(Means for solving problems) Tree 5il! One of Ming's objectives is to reduce the use of expensive Co metal and provide rare earth permanent magnets with magnetic properties equal to or better than Sm-Co magnets, with a heavy duty ratio of 12 to 45%. R (R is at least 174 or more of rare earth elements including Y) and 0.5 to 25% M (M is Z
r, Hf), and the remainder is T (T is F
The gist of the invention is to provide a rare earth permanent magnet consisting of a combination of Fe or a combination of Fe and Co) and unavoidable impurities.

To explain this, as mentioned above, regarding the existence of the conventional RF e s phase, even if the Sm content and the Fe content are adjusted to the ratio of SmFe3, 2:17 phase, 1:2 phase, and Although the existence of three phases of l:3 phase is recognized, l:5
The existence of this phase has not been confirmed.

Therefore, as a result of various studies regarding the third component to be added to the R-Fe system component, the present inventor found that addition of Zr, Hf, or both (M component) is suitable for this, and that R and M
By optimizing the calibration of the components, R-M-Fe can be produced in the bulk state.
The present invention was achieved by discovering that a hitherto unknown ternary compound consisting of (or a combination of Fe and Co) can exist stably.

The rare earth permanent magnet according to the present invention has a noise percentage of 12~
A composition consisting of at least one rare earth element -L containing 45% Y, 0.5 to 25% M component, and the remainder Fe or a combination of Fe and CO and unavoidable impurities, Melting, casting, crushing, molding.

It can be obtained by sintering.

In the formulation of L-, if the rare earth element containing Y is outside the above range, the ternary compound will not be stable, and if it is less than 12%, the coercive force iHc will decrease, and if it is more than 45%, the saturation magnetization will decrease. Furthermore, if the M component is less than 0.5%, the ternary compound will not be stable, and if it is more than 25%, the ternary compound phase will decrease, so it is necessary to use the above-mentioned -1 combination.

The components defined by R above are La, Ce, Pr, and Nd.
, Sm, Eu, Gd, Tb, Dy, 1(o, Er, T
A rare earth element consisting of m, Yb, and Lu, including Y, which may be used alone or in combination of two or more.

On the other hand, in the present invention, replacing a part of Fe added as TQ with Co has the effect of increasing the Curie point by one point, although there are differences depending on the type of R, and also
When the O content ratio is increased, there is a similar tendency to increase the saturation magnetization up to a certain value. However, the percentage of Go is 80%
If it exceeds , the coercive force will decrease and it will be disadvantageous in terms of cost.

When using a combination of Fe and Co, Fe: 40% or more.
In addition, CO: 60% or less;

As mentioned above, in the rare earth permanent magnet obtained by the present invention, the ternary compound phase is stabilized by the introduction of Zr, Hf, or both, so the Curie point and saturation magnetization are improved, resulting in a magnet with high magnetic properties. However, Zr or H
A part of f can also be replaced with Ti.

In addition, this rare earth permanent magnet can be made into an anisotropic sintered magnet by the powder sintering method, so the magnetic properties of
-It can be made equal to or better than Co-based magnets, and since it is a magnet mainly composed of Fe, it has better performance than Sm-Co-based magnets.

Furthermore, thin ribbons with high coercive force can also be produced by the quenched ribbon method, which can be crushed to make isotropic plastic magnets, or anisotropic sintered bodies can be crushed to make anisotropic plastic magnets. It has many uses, including as a magnet.

(Effects of the Invention) As described below, according to the present invention, a hitherto unknown ternary compound phase can be created by adding a predetermined amount of Zr, Hf, or i to an R-Fe magnetic material. Since stabilization has been achieved, even if less expensive Co is used, a permanent magnet with excellent magnetic properties and that can be expected to be used in a wide range of applications can be obtained.

(Example) Various metals each having a purity of 98.9% are shown in Table 1; 1 cup was weighed, melted in a high-frequency melting furnace, and the molten metal was poured into a copper water-cooled G-type to create an ingot. .

This ingot was pulverized by a jet mill in N2 gas to an average particle size of 2 to 10 m. After orienting the obtained fine powder in a static magnetic field of 15 kOe, 1.5 t/crrr
Press molded at a pressure of '. This molded body was subjected to sintering heat treatment at 1000 to 1200°C for 1 hour in Ar gas, then further heat treated at 50G to 900°C for 4 hours, and then rapidly cooled.

Residual magnetic flux density Br of the anisotropic sintered body after heat treatment.

Coercive force iHc, maximum energy m (BH) as aX As a result of the measurement, the results shown in Table 1 were obtained.

Claims (1)

[Claims] 1. 12 to 45% R (R is at least one rare earth element including Y) and 0.5 to 25% M by weight percentage.
(M is at least one of Zr and Hf), and the remainder is T.
(T is Fe or a combination of Fe and Co) and inevitable impurities. 2. The rare earth permanent magnet according to claim 1, wherein the permanent magnet is an anisotropic sintered body.