| 摘要 |
PURPOSE:To obtain a permanent magnet not using expensive and rare Co by molding and sintering alloy powder composed of R, that is, (at least one kind of rare-earth elements containing Y), B, and Fe, cooling thereof after heat treatment, applying secondary heat treatment thereto, and forming thereof. CONSTITUTION:Alloy powder composed of R (R is at least one kind of rare- earth elements containing Y) of 8-30 atomic percentage, B of 2-28atm%, residual Fe, and unavoidable impurities and provided with the average grain size of 0.3-8mum is formed. This is sintered under temperature of 900-1,200 deg.C. After sintering, it is subjected to primary heat treatment under temperature of 750- 1,000 deg.C and then it is cooled down to temperature 680 deg.C or less with the cooling speed of 3-2,000 deg.C/min. Moreover, it is subjected to secondary heat treatment under temperature of 480-700 deg.C. Such a constitution allows a permanent magnet of rare-earth Fe group not using expensive and rare cobalt at all to be obtained. |
