Title:
【発明の名称】改良された磁気材料とその製法
Document Type and Number:
Japanese Patent JPH04500887
Kind Code:
A
Abstract:
This invention relates to a process for producing a rare earth-containing material capable of being formed into a permanent magnet comprising crushing a rare earth-containing alloy and treating the alloy with a passivating gas at a temperature below the phase transformation temperature of the alloy. This invention further relates to a process for producing a rare earth-containing powder comprising crushing a rare earth-containing alloy in a passivating gas at a temperature from ambient temperature to a temperature below the phase transformation temperature of the material. This invention also relates to a process for producing a rare earth-containing powder comprising crushing a rare earth-containing alloy in water, drying the crushed alloy material at a temperature below the phase transformation temperature of the material, and treating the crushed alloy material with a passivating gas at a temperature from the ambient temperature to a temperature below the phase transformation temperature of the material. Additionally, this invention relates to a process for producing a rare earth-containing powder compact comprising crushing a rare earth-containing alloy in water, compacting the crushed alloy material, drying the compacted alloy material at a temperature below the phase transformation temperature of the material, and treating the compacted alloy material with a passivating gas at a temperature from ambient temperature to a temperature below the phase transformation temperature of the material. Rare earth-containing alloys suitable for use in producing magnets utilizing the powder metallurgy technique, such as Nd-Fe-B and Sm-Co alloys, can be used. The passivating gas can be nitrogen, carbon dioxide or a combination of nitrogen and carbon dioxide. If nitrogen is used as the passivating gas, the resultant powder or compact has a nitrogen surface concentration of from about 0.4 to about 26.8 atomic percent. Moreover, if carbon dioxide is used as the passivating gas, the resultant powder or compact has a carbon surface concentration of from about 0.02 to about 15 atomic percent. The present invention further relates to the production of a permanent magnet comprising the above steps, and then sintering the compacted material at a temperature of from about 900 DEG C. to about 1200 DEG C., and heat treating the sintered material at a temperature of from about 200 DEG C. to about 1050 DEG C. An improved permanent magnet in accordance with the present invention can have a nitrogen surface concentration of from about 0.4 to about 26.8 atomic percent if nitrogen is used as a passivating gas. The improved permanent magnet can also have a carbon surface concentration of from about 0.02 to about 15 atomic percent if carbon dioxide is used as a passivating gas.
Inventors:
Bogaytin, Jacob
Application Number:
JP51162190A
Publication Date:
February 13, 1992
Filing Date:
June 13, 1990
Export Citation:
Assignee:
SPSS Technologies, Inc.
International Classes:
B22F1/145; C22C33/02; C22C38/00; H01F1/053; H01F1/055; H01F1/057; H01F1/059; (IPC1-7): B22F1/00; C22C33/02; C22C38/00; H01F1/053
Domestic Patent References:
| JPS60159152A | 1985-08-20 | |||
| JPS6469001A | 1989-03-15 | |||
| JPS62294159A | 1987-12-21 | |||
| JPS60131949A | 1985-07-13 | |||
| JPS5511339A | 1980-01-26 |
Foreign References:
| US4322257A | 1982-03-30 | |||
| US4043845A | 1977-08-23 |
Attorney, Agent or Firm:
Yuzo Yamazaki (2 outside)