COMPOSITE RARE EARTH ANISOTROPIC BONDED MAGNET, COMPOUND FOR COMPOSITE RARE EARTH ANISOTROPIC BONDED MAGNET AND METHOD FOR PREPARATION THEREOF

摘要

A composite rare earth anisotropic bonded magnet which comprises a NdFeB type coarse powder surface-coated with a surfactant, a SmFeN type coarse powder surface-coated with a surfactant and a resin as a binder, wherein both coarse powders have specific average particle diameters, respectively, and are contained in a specific compounding ratio, and wherein almost all the constituent particles of the NdFeB type coarse powder are surrounded by a ferromagnetic fluid layer comprising the resin and the SmFeN type coarse powder dispersed uniformly in the resin and the clearance formed between constituent particles of the NdFeB type coarse powder is closely filled with the fluid layer. The above-mentioned fulfillment of the clearance has lead to the preparation of a bonded magnet which combines excellent magnetic characteristics and markedly little deterioration with elapsed years.