| abstract |
ABSTRACT A rare earth-iron-boron alloy powder which consists essentially of: 12.5 to 20 at % R wherein R1 is 0.05 to 5 at %, 4 to 20 at % B, and 60 to 83.5 at % Fe, wherein R1 is at least one heavy rare earth element selected from the group consisting of Gd, Tb, Dy, Ho, Er, Tm and Yb, 80 to 100 at % of R2 consists of Nd and/or Pr, the balance in the R2 being at least one element selected from the group consisting of rare earth elements including Y and except for R1, and R = R1 + R2 by atomic %, wherein a major phase of at least 80 vol % of the entire alloy coinsists of a tetragonal structure, and wherein oxygen does not exceed 10000 ppm, carbon does not exceed 1000 ppm and calcium does not exceed 2000 ppm. The alloy powder is produced by directly reducing a mixture comprising rare earth oxide, iron and other ingredients or oxide thereof with a reducing agent Ca and CaCl2, putting the reduced product into water, then treating with water. Up to 35 at % Co may be substituted for Fe. |