New sintered high temperature Sm-Co based permanent magnet materials

Abstract

New sintered Sm-Co based permanent magnet materials have been developed to meet the high-temperature (/spl ges/400/spl deg/C) application requirement of advanced power systems. A magnet of Sm(Co/sub bal/Fe/sub 0.09/Cu/sub 0.09/Zr/sub 0.03/)/sub 7.69/ shows an intrinsic coercivity (/sub M/H/sub c/) approaching 13 kOe and an energy product of 14 MGOe at 400/spl deg/C. Its second-quadrant induction demagnetization curve is a straight line at temperatures to 500/spl deg/C. Magnets with improved temperature coefficient of /sub M/H/sub c/ have been obtained by reducing the Fe content and increasing the Sm content. An abnormal and complex temperature dependence of MIE was observed in sintered Sm(Co/sub bal/Fe/sub 0.04/Cu/sub 0.09/Zr/sub 0.02/)/sub 7.26/. Upon heating, the /sub M/H/sub c/ first reached a minimum of 4.4 kOe at 150/spl deg/C and then gradually increased to a maximum of 7.5 kOe at 500/spl deg/C.