| 摘要 |
PURPOSE:To lower the temperature of sintering as well as to obtain the permanent magnet having excellent magnet characteristics by a method wherein a gas-removing process is performed under a specific condition before the alloy powder to be used for the manufacture of rare-earth magnet is sintered. CONSTITUTION:The quantity of evaporation of the samarium in the process of sintering is relatively large in the case of untreated powder. Also, as said powder is sintered in the state wherein the samarium and the like is grown on the surface of powder, a large quantity of oxide is contained in the vicinity of grain boundary inside a sintered body. Consequently, a two-phase isolation is obstructed when an aging treatment, wherein magnetic characteristics are determined, is performed and the characteristics are deteriorated. When a gas- removing treatment is performed, as a preparatory treatment is performed subsequently at the temperature range of 200-600 deg.C for 5 minutes - 4 hours in the vacuum atmosphere of 1X10<->STorr or below, the temperature of sintering of the untreated powder can be lowered, thereby enabling to sinter the powder without deterioration of the magnetic efficiency of the powder itself. |
