摘要 |
PURPOSE:To easily produce the alloy powder of rare earth system for a permanent magnet having excellent magnetic characteristics by subjecting alloy powder having a specific compsn. consisting of rare earth elements, iron family elements and Ti, etc., to a heating treatment in gaseous H2 from a hydrogen storage material. CONSTITUTION:The cast ingot of the alloy consisting of 7 to 9at.% R (R: rare earth elements contg. >=50% Pr or Nd), 67 to 90.5% T (T: Fe or <=50% thereof is substd. with Co, Ni), 3.5 to 17% M (M: Ti, V, Cr, Mo) is roughly pulverized. The roughly pulverized powder having 50 to 500mum average grain size and >=80% tetragonal structure ThMn12 type compd. is obtd. This powder is held for 30 minutes to 8 hours at 500 to 900 deg.C in gaseous H2 kept at 10 to 1000kPa and is then subjected to an H2 removal treatment at <=10Pa partial pressure. The hydrogen storage material is used as the main supply source for the above- mentioned gaseous H2 at this time. The resulted powder of 0.05 to 1mum is held for 30 minutes to 6 hours at 300 to 600 deg.C in the gaseous N2 of 50 to 5000kPa, by which 0.8 to 8% N is incorporated therein and the alloy powder of rare earth system for a permanent magnet is stably obtd. |