| 摘要 |
PURPOSE:To obtain a magnetic powder for producing Nd-Fe-B plastic magnet which is improved all characteristics of density, residual magnetic flux density, coercine force, and maximum energy product, by using a material having Nd, Fe, and B as main constituents, and oxygen content below a specified value with its grain size to be within a specified range. CONSTITUTION:The main constituents of magnetic powder are Nd, Fe, and B, the grain size measured by a screen prescribed by the JISZ8801 is 80-150 mesh, and the oxygen content is equal to or less than 0.1weight%. For example, an alloy with a composition of Nd 30weight%, B 0.7weight%, Si 0.1weight%, Co 3weight%, and the remainder Fe is fused in an Ar environment of 100-900Torr and the obtained alloy fused liquid is sprayed to the periphery surface of Cu drum which rotates at 300rpm to produce alloy flakes. Then, after the flake is ground within atmosphere, a powder within the gain size range above is obtained using a screen prescribed by the JISZ8801, heat treatment is performed to the powder under a vacuum of 1X10<-3>Torr at 650 deg.C for 0.5hr, and then a magnetic powder with an oxygen content of 0.07weight% is obtained. |
