| 摘要 |
PURPOSE:To be able to manufacture a rare earth magnet having stable magnet characteristics with good reproducibility by pulverizing rare earth alloy foil blank in which at least part is formed in an amorphous state as a flat rare earth alloy powder, pressure molding the powder by utilizing explosion force and heat treating it to impart magnetic characteristics thereto. CONSTITUTION:Molten rare earth alloy is cooled at an ultrahigh speed to form a rare earth alloy foil blank in which at least part is formed in an amorphous state, the foil blank is pulverized as a flat rare earth alloy powder. This powder is molded under pressure by utilizing an explosion force, and the molding is heat treated to impart magnetic characteristics. For example, the molten rare earth alloy of the composition of Nd13.0Fe82.5B4.5 is injected to the surface of a copper single roll which rotates at a high speed to be cooled at an ultrahigh speed to form a rare earth alloy foil blank having a thickness of approx 20mum, the blank is finely pulverized in a nitrogen atmosphere as a flat rare earth alloy powder 150mum or smaller longitudinal size. This is inserted into a bottomed cylinder of stainless steel, dynamic entropy of approx. 8GPa is applied to in form a molding, which is then allowed to stand at 700 deg.C in a vacuum for 30 min., magnetic characteristics are imparted by heat treating under the condition of furnace cooling. |
