Title:
ANISOTROPIC RARE EARTH ALLOY POWDER FOR PERMANENT MAGNET AND ITS PRODUCTION
Document Type and Number:
Japanese Patent JP3086334
Kind Code:
B2
Abstract:
PURPOSE: To obtain an alloy powder improved in magnetic anisotropy, increased in residual magnetic flux density at the time of being formed into magnet, and having superior magnetic properties by specifying the composition of a rare earth alloy for permanent magnet and replacing a part of B by C.
CONSTITUTION: An alloy powder having a composition containing, by atom, 10-20% R (where R means rare earth elements and containing ≥50% Pr and/or Nd), 67-85% T (where T means Fe or a part of Fe is replaced by ≤50% Co), and B by the amount in the range where C content satisfies (B+C=4 to 10%) and C/(B+C) becomes 0.01-0.8 is prepared. This raw material powder is heated and held at 500-900°C for 15min-8hr in an H2 gas of 10-1000KPa. The powder is further held at 500-900°C for 15min-8hr at ≤10Pa partial pressure of H, to undergo dehydrogenation, followed by cooling. By this method, the alloy powder where ≥70vol.% of alloy powder has tetragonal Nd2Fe14B type crystalline structure and ≥ at least 50vol.% of crystals have 0.05-1μm grain size and which has 10-1000μm average grain size and 0.9-1.6T residual magnetic flux density in a direction of easy magnetization can be obtained.
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Inventors:
Hiroyuki Tomizawa
Akira Hirosawa
Akira Hirosawa
Application Number:
JP17907592A
Publication Date:
September 11, 2000
Filing Date:
June 12, 1992
Export Citation:
Assignee:
Sumitomo Special Metal Co., Ltd.
International Classes:
B22F9/04; C22C33/02; C22C38/00; H01F1/053; H01F1/058; H01F1/06; B22F1/00; (IPC1-7): C22C33/02; B22F1/00; B22F9/04; C22C38/00; H01F1/053; H01F1/06
Domestic Patent References:
| JP382744A | ||||
| JP1261801A | ||||
| JP63213315A | ||||
| JP6398105A | ||||
| JP62119903A | ||||
| JP1132106A |
Attorney, Agent or Firm:
Yoshihisa Oshida