New sintered high temperature Sm-Co based permanent magnet materials

New sintered Sm-Co based permanent magnet materials have been developed to meet the high-temperature (greater than or equal to 400 degrees C) applicat ion requirement of advanced power systems. A magnet of Sm(CobalFe0.09Cu0.09 Zr0.03)(7.69) shows an intrinsic coercivity (H-M(c)) approaching 13 kOe and an energy product of 14 MGOe at 400 degrees C. Its second-quadrant inducti on demagnetization curve is a straight line at temperatures to 500 degrees C. Magnets with improved temperature coefficient of H-M(c) have been obtain ed by reducing the Fe content and increasing the Sm content. An abnormal an d complex temperature dependence of H-M(c) was observed in sintered Sm(Coba lFe0.04Cu0.09Zr0.02)(7.26) Upon heating, the H-M(c) first reached a minimum of 4.4 kOe at 150 degrees C and then gradually increased to a maximum of 7 .5 kOe at 500 degrees C.