| 摘要 |
PURPOSE:To obtain an inexpensive Nd anisotropic permanent magnet having a high temperature characteristic by shaping an alloy of R-Fe-Co-B fundamental composition into flake powder by the melt spin method and heat-treating the powder to make an anisotropic magnet. CONSTITUTION:An alloy consisting of for example 13at.% of Nd and Pr, 17.8at.% of Co, 5.8at.% of B, and Fe is quenched and solidified by the melt spin method and shaped into flake powder and crystal grains are made by heat treatment. The flake is put into a space 3 defined by a ceramic cavity 1 and a pair of electromagnetic punches 2 and 2', a pressure is exerted on the electromagnetic punches 2 and 2' to produce a higher vacuum atmosphere, DC voltage is applied, a direct current is directly passed, and cooling is carried out to obtain a permanent magnet. The relative density of the magnet is 95% or higher, the residual magnetic flux density thereof is 9.5KG or higher, and the intrinsic coercive force thereof is 10KOe or more. The temperature coefficient of the residual magnetic flux density is -0.09%/ deg.C or lower and that of the intrinsic coercive force is -0.5%/ deg.C or lower. |
