JPS6221858B2 - - Google Patents

Description

1 R(Co _1-xy- 〓 _- 〓FexCuyHfαCaβ)A (Here, R: Sm, one type or combination of two or more rare earth elements centered on Ce, 0.01≦x≦0.4, 0.02≦y≦0.25 0.001 ≦α≦0.15, 0.001≦β≦0.15 6.0≦A≦8.3) A permanent magnet alloy characterized by having the following composition.

[Detailed description of the invention]

The present invention relates to an intermetallic compound consisting of a rare earth metal and Co, and particularly to the improvement of a Cu-added R ₂ Co ₁₇ permanent magnet alloy with a low rare earth component. Sm, Ce
A rare earth metal (hereinafter referred to as R) consisting of one kind or a combination of two or more rare earth elements, mainly
R containing Co, Fe, and Cu (Co _1-xy Fe _x Cu _y )
A, 0.01≦x≦0.20, 0.05≦y≦0.25, 6.5≦A≦
The alloy represented by 8.0 is known as a permanent magnet material with excellent residual magnetic flux density (Br) and coercive force _{( BHC} , _{IHC )} . (For example, Japanese Patent Application Laid-Open No. 1397-1983). The above alloy has already achieved an energy product ((BH)max) of as much as 25MGOe, and various applications that take advantage of this property have already been carried out.

However, in the above magnet system, the amount of Cu substitution required for precipitation hardening was large, causing a decrease in Br, and the limit was about Br ~ 10,500G. Furthermore, the decrease in the Curie point due to this Cu substitution also resulted in a decrease in thermal stability. On the other hand, excessive Fe substitution is effective in increasing Br.
Since Fe substitution lowers the coercive force, the desirable Fe substitution amount x is limited to 0.1. Furthermore, since A required to obtain sufficient coercive force and squareness of the hysteresis curve is 7.0 to 7.5, high Br could not be obtained.

In order to improve these defects, we investigated the addition of H _f and obtained properties of approximately 29 MGOe in the high Fe and low Cu region. (Patent Application No. 52-20234) That is, Sm
(Co ₀ . ₆₉ Fe ₀ . ₂ Cu ₀ . ₁₀ Hf ₀ . ₀₁ ) _7. As seen in the representative composition of ₄ , the Fe substitution amount was increased (0.1 → 0.2) and the Cu substitution amount was decreased (0.15 → 0.1). , 4πIr~11000G.

An object of the present invention is to develop the above technology and provide a new and extremely useful permanent magnet.

In order to achieve the above object, the present invention further provides H _f
By adding Ca in combination to shorten the heat treatment time and increase the amount of Fe substitution, the amount of Cu substitution necessary for sufficient precipitation hardening is reduced, and a permanent magnet with even higher magnetic properties is obtained. It is. As a result of various experiments, the inventors have found that the heat treatment time can be shortened by adding H _f +Ca in combination. Addition of Ca also makes it possible to moderate the cooling rate after solution treatment, which has a great positive effect on heat treatment.

The addition of Ca generally reduces the Curie point Br
decreases, but the Curie point hardly changes as the amount of Cu substitution decreases to some extent by adding Ca, and Br also increases because the amount of Fe substitution can be increased.

In the present invention, if the amount of Ca added is less than 0.001, no positive effect on heat treatment can be expected;
If it exceeds 0.15, deterioration of magnetic properties due to a decrease in Br and deterioration of thermal stability due to a decrease in the Curie point occur, making it undesirable as a permanent magnet material. On the other hand, if the amount of H _f added is less than 0.001, sufficient _I H
If _C cannot be obtained or exceeds 0.15, Br and the Curie point decrease, making it undesirable as a permanent magnet material like Ca. Fe substitution generally increases Br but leads to a decrease in _I H _C. Especially when using the additive according to the present invention, it is useful for increasing Br.
Even if the amount of Fe substitution is added, the decrease in coercive force is small, so the amount of Fe substitution can be increased compared to the case without addition.

If the Fe substitution amount is less than 0.01, it will have little effect on increasing Br, and if it exceeds 0.4, it will lead to a decrease in coercive force.

When the amount of Cu substitution is less than 0.02, sufficient coercive force cannot be obtained as a so-called precipitation hardening permanent magnet material even if the additive according to the present invention is used. If the amount of Cu substitution exceeds 0.25, the present invention cannot be utilized due to a decrease in Br.

When the value of A is less than 6.0, Br is low, and when it exceeds 8.3, dendrite (Co, Cu, Fe, rich phase) is generated, which is not desirable as a permanent magnet material.

The present invention will be explained below with reference to Examples.

Example _{1 An alloy of Sm(Co0.66Fe0.23Cu0.09Hf0.01Ca0.01) 7.4 was melted by high frequency and} coarsely _ground using a Joe Crusher _Brown Mill _. , finely pulverized using a jet mill. The grinding media is _N2 gas and the fine powder particle size is 45μ. This crushed powder
After orientation in a magnetic field of 15 KOe, compression molding was performed using a hydrostatic press at a pressure of 2 tons/cm ² . The obtained molded body was vacuum sintered at 1190°C for 1 hour. 1180℃ after sintering
It was solutionized for 0.5hr and quenched in water. Further 800℃×
Added 2hrs statute of limitations.

The obtained magnetic properties were Br~11400G _BHC ~ _{6300Oe IHC} ~ _6700Oe (BH)max~31.2MGOe.

Example _{2 An alloy of Sm(Co0.678Fe0.22Cu0.08Hf0.012Ca0.01)7.2 was pulverized , compression molded , and} sintered in the same manner as _{in Example 1} . After sintering, solution treatment is performed at 1180℃ x 1hr.
Quenched in Si oil. Further 800℃×2hrs＋700
Aging was performed at ℃×2hrs.

The obtained magnetic properties were Br~11400G _BHC ~ _{6200Oe IHC} ~ _6500Oe (BH)max~32.0MGOe.

As stated above, the permanent magnet alloy of the present invention
Shorter heat treatment time compared to the case of adding Hf alone,
It makes it possible to moderate the cooling rate after solution treatment, and has the effect of increasing Br without changing the Curie point.

Claims (1)

[Claims]