| 简介 |
PROBLEM TO BE SOLVED : To provide a heat-resisting rare earth magnet capable of holding high coercive force and remanent flux density, and suppressing heat generation due to eddy currents even when the content of rare earth elements such as rare Dy is reduced. SOLUTION : In an Nd-Fe-B group rare earth magnet, an M (M is Tb/Dy) element is dispersed to ≥0.3μm depth from a surface, the content of the M element is 0.05-5 mass% and oxygen of 0.4-3 mass% is contained. The M element infiltrated into a grain boundary by the diffusion exists as a (Nd, M) O2group compound. For instance, M metal, alloy containing the M metal or the hydride or oxide of the M metal is decomposed into atoms, molecules or ions in a pressure reducing tank to form a film on the surface of the Nd-Fe-B group magnet, and simultaneously with or successively to the film formation, the Nd-Fe-B group magnet is heat-treated in an atmosphere including oxygen and the M element and oxygen are diffused and infiltrated from the surface of the magnet into the inside to manufacture the heat-resisting rare earth magnet. Consequently, the heat-resisting rare earth magnet of which the specific resistance is ≥5 μΩ m and the coercive force is ≥2MA/m is obtained. COPYRIGHT : (C)2005, JPO&NCIPI |
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