| 摘要 |
Permanent magnets formed from rare earth cobalt compounds have high energy products. One rare earth cobalt composition, formulated by metallurgical sintering techniques, is a composition of a rare earth and cobalt such as samarium and cobalt containing about 37.2 weight per cent samarium which corresponds to 60 proportions of SmCo5 for each 40 proportions of Sm2Co7. This composition is an excellent permanent magnet having an energy product at least as high as 15 x 106 gauss-oersteds and up to 20 x 106 gauss-oersteds or higher. SmCo5 contains roughly 33.8 weight per cent samarium, and Sm2Co7 about 42.2 weight per cent samarium; I have found that samarium-cobalt materials containing samarium between about 36.5 weight per cent and about 38 weight per cent are preferred and can be developed into magnets of greatly improved properties. The samarium-cobalt magnet of this invention is basically comprised of crystals of SmCo5 and Sm2Co7 wherein the SmCo5 crystals are surrounded by growth-inhibiting materials and are not larger than single domain size.
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