JPS63502B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing rare earth stones by molding, sintering, and various heat treatments a powder of an alloy consisting of rare earth elements, transition metals, Cu, Ag, and one or more other elements. In order to obtain high magnetic properties, aging heat treatment after _sintering is important, but conventional aging heat treatment cannot produce rare earth magnets with excellent magnetic properties, especially coercive force (referred to as _IHC ). Has no drawbacks. An object of the present invention is to improve the above-mentioned drawbacks and provide a manufacturing method related to aging heat treatment that makes it possible to obtain a magnet with excellent magnetic properties, particularly excellent coercive force. Rare earth magnets contain one or more of the rare earth elements Sc, Y, La, and 17 elements with element numbers 58 to 71, as well as transition metals.
The main components include Fe, Ni, Mn, Cr, Co, Ti, Zr, Hf, W, etc., as well as Cu, Ag, and other elements as additive elements.
A group such as Be, Mg, etc., A group such as Zn, Cd, B, Al etc.
Group, A group such as C, Si, P, Se, Bi, A,
It is known that it includes group A and the like. As these alloy compounds, when R is a rare earth element and M is another element, R ₃ M,
R ₉ M ₄ , RM ₂ , RM ₃ , R ₂ M ₇ , R ₅ M ₁₉ , R ₁ M ₅ ,
It is also known that a substance represented by R ₂ M ₁₇ exists. The alloy composition of the present invention concerns R ₂ M ₁₇ therein, with R being limited to between 20 and 34% by weight.
These melted alloy ingots are pulverized into powders of 10μ or less using a pulverizer or ultrafine pulverizer, and then pressed into compacts in a magnetic field of 5,000 to 15,000 oersteds, and thoroughly degassed. After that, sintering is carried out at a temperature range of 1000-1300°C. After that, it is subjected to solution and other treatments at the same temperature, and then rapidly cooled by blowing argon gas, or in water, oil, salt bath, etc. Then 800℃~950℃
Aging heat treatment is performed within the range of . In conventional methods, after this aging heat treatment, the material is rapidly cooled, multi-stage aging treatment is performed, or even slow cooling is performed at the level of furnace cooling. The present invention differs from conventional methods in that it involves very slow slow cooling to bring the material to room temperature, and a method in which rapid cooling is performed only once in the range of 700°C to 500°C, followed by slow cooling. In other words, good results can be obtained by slowing the slow cooling rate after aging heat treatment to less than 150°C/hour, but from an industrial value point of view,
150°C/hour to 10°C/hour is preferred. In addition, in the middle of the above gradual cooling, the temperature range is 700°C to 500°C, and quenching is performed by spraying argon gas or dust gas, or by quenching in an oil, salt bath, or melt metal bath, and then the cooling rate is the same as above. This method involves slow cooling and bringing it to room temperature. However, in order to save time, temperatures below 700°C may be rapidly cooled to room temperature if some deterioration of magnetic properties is allowed. The present invention will be explained below with reference to Examples. Example 1 An alloy consisting of 24% by weight of Sm, 20% of Fe, 10% of Cu, 1.5% of Zr, and the remainder Co was produced in a high-frequency melting furnace in argon. Thereafter, it was ground to about 4 μm using a ball mill, vibration mill, and jet mill. After that, it was molded in a magnetic field press at 5t/cm ² in 9500 Oersted, vacuum degassed at 400℃ for 1 hour, sintered at 1190℃, solution heat treated at 1170℃, and then quenched in silicone oil. . After aging heat treating this sample at 850℃ for several hours, the cooling rate shown below was changed.
The results of investigating magnetic properties are shown. Among the magnetic properties, the residual magnetic flux density Br is constant and Br=10250 Gauss.

【table】

[Table] Also shows the results of an experiment to investigate the temperature range for rapid cooling at a cooling rate of 80°C/hour.

[Table] As shown above, cooling rate 150℃/hour ~ 10℃/hour
It can be seen that the coercive force increases significantly with time. Further, at 80°C/hour, a further increase in coercive force can be obtained in the temperature range of 700°C to 500°C during rapid cooling (immersion in a salt bath). Example 2 Sm29% by weight, Fe25%, Cu8%, Ag2%, Ni,
Mn, Cr, Zr, Ti, Hf, W in total 2%, Zn, Be,
The same trend as in Example 1 was obtained using a composition of 0.5% each and the remainder Co. Example 3 Sm15% by weight, Pr12%, Fe15%, Cu10%, Zr,
Similar trends were obtained for the compositions of Ti, W, and each with 0.5% remaining Co. Example 4 The same was true in the case of 27% by weight of Sm, 15% of Fe, 10% of Cu, 1.5% of W, and the remainder Co.

Claims (1)

[Claims] 1. 20 to 34% by weight of one or more rare earth elements, the rest
Cu, Ag, and Fe, Ni, Mn, Cr, Co, Zr,
Compression molding, sintering of alloy powder consisting of transition metals such as Ti, Hf, W, and one or more other elements,
In the method of manufacturing magnets by aging heat treatment,
A method for manufacturing a rare earth magnet, which comprises slowly cooling the magnet at a cooling rate of 150° C./hour to 10° C./hour after aging heat treatment. 2. Claim 1 characterized in that after aging heat treatment, quenching is performed only within a temperature range of 700°C to 500°C.
2. Method for manufacturing rare earth magnets described in Section 1.