METHOD FOR MANUFACTURING ALLOY POWDER FOR R-Fe-B SINTERED-TYPE PERMANENT MAGNET

PROBLEM TO BE SOLVED : To provide a method for manufacturing alloy powder for a R-Fe-B (R is one or more kinds among rare earth elements including Y) sintered-type permanent magnet suitable for improving the corrosion resistance of an R-Fe-B sintered-type permanent magnet. SOLUTION : The permanent magnet alloy powder can be manufactured by; subjecting an R-Fe-B (R is one or more kinds among rare earth elements including Y) rapidly solidified cast alloy to heat treatment at 800 to 1, 100°C in an inert gas atmosphere or practically in vacuum, applying hydrogen absorption treatment and dehydrogenation treatment to the resultant heat treated R-Fe-B rapidly solidified cast alloy, and then carrying out pulverization; or by pulverizing an R-Fe-B sintered-type permanent magnet alloy using a jet mill in a state where the inside of the jet mill is formed into an atmosphere of a gaseous mixture of Ar gas and N2 gas (N2 gas concentration in the gaseous mixture atmosphere is 0.0001 to 0.1 vol% and oxygen concentration is practically 0%).