| 摘要 |
PURPOSE:To obtain the titled alloy powder having the magnetic characteristics which can be fully satisfied by a method wherein powderly rare-earth oxide, a reducing agent, Fe and other metal or oxide powder and B2O3 oxide powder are mixed, they are subjected to reduction and diffusion at a fixed temperature in a reducing gas atmosphere and cooled in an inert gas atmosphere. CONSTITUTION:A rare-earth oxide, a kind of granular Ca and Mg, Fe powder and other metal powder or the oxide powder of a part of whole of them, and B2O3 oxide powder are mixed. They are heated up to the temperature of 90 deg.C or less in an Ar gas or H2 gas atmosphere, and their reduction is performed. When the Ca and Mg is turned to the state of liquid phase and a reduction-diffusion reaction is applied thereto simultaneously at T=900-1,200 deg.C in an H2 gas atmosphere while they are being heated up, the entire metal oxide is reduced because vapor pressure is boosted. Also, the surface of each reduced alloy element, containing a rare-earth metal, is activated by H2 gas. Accordingly, diffusion reaction makes progress rapidly, and excellent magnetic characteristics are obtained by molding and sintering processes and a heat treatment. After they are reacted, the cooling work is performed at the temperature of 900 deg.C or below in the inert gas atmosphere such as Ar gas and the like, and the removal of H2 gas is performed on a low temperature region. |
