Patent ID: 6287391
Filing Date: 2001-09-11
Classification: H01F

Abstract:
A method for manufacturing a layered permanent magnet for manufacturing a unified permanent magnet of a fine crystal structure having an average crystal grain size of 10 nm to 50 nm, said method comprising the steps of:processing a molten alloy by a rapid cooling method adopting a rotating roll in an inert gas atmosphere of less than 30 kPa, the molten alloy of which having a formula represented by Fe.sub.100-x-y R.sub.x A.sub.y, (Fe.sub.1-m Co.sub.m).sub.100-x-y R.sub.x A.sub.y, Fe.sub.100-x-y-z R.sub.x A.sub.y M.sub.z, or (Fe.sub.1-m Co.sub.m).sub.100-x-y-z R.sub.x A.sub.y M.sub.z, wherein R is at least one or two elements selected from the group consisting of Pr, Nd, Dy and Tb; A is one or two elements selected from the group consisting of C and B; and M is at least one or two elements selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, Pb, and wherein the symbols x, y, z and m, each for limiting the compositional range, satisfy the values 1.ltoreq.x<6 at %, 15.ltoreq.y.ltoreq.30 at %, 0.01.ltoreq.z.ltoreq.7 at %, 0.01.ltoreq.m.ltoreq.0.5 at %;forming rapidly cooled thin alloy strips having at least 90% amorphous structure and an average thickness of from 10 .mu.m to 200 .mu.m;laminating the thus formed rapidly cooled thin alloy strips as they are or after working them to be a desired shape to form a layer having a desired thickness;subjecting the thus formed layer to a crystallization heat treatment at a temperature of 550.degree. C. to 750.degree. C.; andadhering the laminated rapidly cooled thin alloy strips to one another by impregnating them in resin.