Process for producing magnets having improved corrosion resistance
AssigneeSumitomo Special Metals Co., Ltd.
InventorsTakaki Hamada, Tetsuji Hayakawa, Yutaka Matsuura
Life of this patent
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Abstract
Fe-B-R type permanent magnet is produced by: forming an anticorrosive coating film layer on a Fe-B-R base permanent magnet material body by means of vapor deposition to thereby improve the corrosion resistance thereof. The anticorrosive thin film is formed of metal, oxides, nitrides, carbides, borides, silicides, composite compositions thereof, or a mixture thereof. Additionally blasting, shot peening, heat treatment for forming an interdiffusion layer, and/or resin impregnation may be applied.
Claims45
A process for producing a permanent magnet, comprising:
- providing a sintered permanent magnet body consisting essentially of 10-30 at % R, wherein R is at least one element selected from the group consisting of Nd, Pr, Dy, Ho and Tb or a mixture of said at least one element and at least one other element selected from the group consisting of La, Ce, Sm, Gd, Er, Eu, Tm, Yb, Lu, Pm and Y, 2-28 at % B and at least 42 at % Fe, and wherein at least 50 vol % of the entire magnet material body consists of a Fe-B-R type tetragonal crystal structure;
- preparing the surface of the permanent magnet material body by blasting;
- and
- then forming a low gas permeability anticorrosive coating film layer on the permanent magnet material body by means of vapor deposition so that corrosive substances do not remain in the resultant permanent magnet, thereby improving the corrosion resistance of the resultant permanent magnet.
A process for producing a permanent magnet, comprising:
- providing a sintered permanent magnet body consisting essentially of 10-30 at % R, wherein R is at least one element selected from the group consisting of Nd, Pr, Dy, Ho and Tb or a mixture of said at least one element and at least one other element selected from the group consisting of La, Ce, Sm, Gd, Er, Eu, Tm, Yb, Lu, Pm and Y, 2-28 at % B and at least 42 at % Fe, and wherein at least 50 vol % of the entire magnet material body consists of a Fe-B-R type tetragonal crystal structure;
- and
- forming a low gas permeability anticorrosive coating film layer on the permanent magnet material body by means of vapor deposition so that corrosive substances do not remain in the resultant permanent magnet, thereby improving the corrosion resistance of the resultant permanent magnet.
Dependencies are inferred from the claim text.