| 摘要 |
Rare-earth alloy anisotropic powders consist of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one on neodymium and praseodymium or at least one of them and or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists of iron and unavoidable impurities. Up to 20 percent of the iron contained is replaceable with cobalt. The alloy powders are made up of flat crystal grains having mean thickness h (the shortest measure), d not smaller than 0.01 mu m and not larger than 0.5 mu m and ratio d/h not smaller than 2, where d is the means measure of the grains taken at right angles to the widthwide direction thereof, and the alloy powders are magnetically anisotropic. Each rare-earth alloy anisotropic powder is prepared by melting an R-Fe-B-Cu alloy, putting thin ribbons prepared by quenching the melt or a powder prepared by grinding the thin ribbons in a metal container, hermetically sealing the metal container after replacing its inner atmosphere with a vacuum or an inert gas atmosphere, and rolling the thin ribbons or powder, together with the metal container, at a temperature not lower than 500 DEG C. and not higher than 900 DEG C. Rare-earth alloy anisotropic magnets are made by kneading and forming the rare-earth alloy anisotropic powders with not less than 10 percent and not more than 50 percent by volume of resin or by hot-compressing the rare-earth alloy anisotropic powders. |
