Technology of melting REM-Fe-Co-B alloys for thermally stable magnets

Abstract

A technology of making REM-Fe-Co-B (REM = rare-earth metal) alloys for thermally stable magnets is developed. This technology ensures a stable chemical composition (REM content deviation of ±1.0 wt % from the calculated value, Co and B content deviation of ±0.5 wt %) and a low impurity content (Al or Ni [less than or equal to] 0.2 wt %, [O] [less than or equal to] 0.1 wt %). This technology makes it possible to make Pr-Dy-Fe-Co-B alloys and more complex compositions with additional REM, e.g., gadolinium. Fe-Pr and Fe-Dy master alloys are chosen and melted, and the possibility of using them to make Pr-Dy-Fe-Co-B alloys is studied.