Rare earth bonded magnet

Abstract

Abstract PURPOSE:To obtain a magnet excellent in heat resistance and oxidation resistance by using a resin of thermosetting polyimide system or a mixed resin containing it by 30wt.% or more as the binder when bonding a fine rare earth alloy powder by means of an organic binder to make a magnet, and blending these resins by 1-5wt.% to the fine powder. CONSTITUTION:A coarse rare earth alloy powder such as SmCo containing 33.8% of Sm for instance obtained by the reduction diffusion process is prepared as the raw material powder and is ground by a ball mill into a fine powder having a particle diameter of about 7mum. On the other hand, as a resin of the thermosetting polyimide system, bismaleimide-triazine resin is used which is liquid at normal temperatures, and it is blended in the proportion of 3% to 97% of the fine powder, added with appropriate acetoned, and they are mixed in the mill into a slurry. Thereafter, the acetone is vaporized and removed from the slurry, which is simultaneously granulated, compression molded in a magnetic field of 15kOe and at a pressure of 5ton/cm<2>, and preserved at 220 deg.C for 10 hours setting the resin to make a magnet.

Inventors

• 👤 Takuo Takeshita
• 👤 武下　拓夫
• 👤 Hiroyuki Baba
• 👤 馬場　洋之

Bibliographic Details