| 摘要 |
PURPOSE:To improve pulverization efficiency and yield by incorporating a specific ratio of gaseous CO2 into an inert gas at the time of pulverizing this powder of an R-T-B system (R is an La system, etc., T is a transition metal) by a jet mill. CONSTITUTION:The gaseous CO2 is incorporated at 50 to 100000ppm into the inert gas to be used as a pulverizing gas at the time of pulverizing the raw material alloy for a rare earth magnet of the R-T-B system to be used as a permanent magnet material by the jet mill. Where, R denotes La and >=1 kinds of rare earth elements including Sc and Y, T denotes >=1 kinds of transition metals. As a result, the silver halide photographic sensitive material powder surfaces are oxidized by a slow speed and the flocculation of the magnetic powders with each other and the sticking to the inside walls of the jet mill are prevented, by which purposes are attained. The raw material alloy of the rare earth magnet is preferably embrittled by hydrogen before pulverization by the jet mill. |
