| 摘要 |
PURPOSE:To enable obtaining a permanent magnet including a large-sized and integral shape with a very small inclination in the magnetizing direction by specifying the orientation of magnetic crystal grains in the easily magnetizing direction after sintering and heat-treating an Nd(R)-Fe-B permanent magnet. CONSTITUTION:The ingot of Nd-Fe-B permanent magnet alloy is made and magnetic powders obtained by rough crushing and jet-mill crushing of the ingot are packed into the die of a cavity having the relation A>=B>C between the major side or major axis A, minor side or minor axis B and thickness C and are preformed under a hydrostatic pressure of 0.7ton/cm<2>. Then, a preformed body contained in a rubber mold is subjected to CIP forming under the hydrostatic pressure of 3t/cm<2> so that a formed boy is obtained. The obtained formed body is sintered in vacuum and thereafter reheated and cooled. When the length of the minor side out of other two sides relative to the thickness (c) in the anisotropic direction is (b), the ratio of b/c is within the range of 0.5-15. Further, the orientation of magnetic crystal grains in the easily magnetizing direction is 90% or more. |
