Permanent magnet alloy having improved resistance to oxidation and

Abstract

A permanent magnet made of an R-Fe-B-C or R-Fe-Co-B-C based alloy (where R is at least one rare-earth element) consisting of its individual magnetic crystal grains that are covered with an oxidation-resistant protective film is promising as a practicable next-generation magnet because of its having not only excellent magnetic properties inclusive of magnetic force that surpasses Sm-Co based magnets but also such highly improved oxidation resistance that may withstand use in practical applications for a prolonged time period without being coated on its outermost exposed surface with an oxidation-resistant protective film. Said protective film surrounding the individual magnetic crystal grains contains at least one, preferably substantially all, of the alloying elements of which said magnetic crystal grains are made, with 0.05-16 wt. %, preferably 0.1-16 wt. % of said protective film being composed of C.