Achieving optimum loop shapes in quaternary Pr-Co alloys

The magnetic properties and microstructures of a quaternary Pr-Co-Ti-C allo y were investigated. After heat treating at 800 degrees C, the quaternary a lloy developed high coercivity (16.7 kOe) and high energy product (8.6 MGOe ). Hysteretic loop shapes exhibiting single-phase magnetic character were a chieved which was a problem which previously plagued development of Pr-Co a lloys. The optimum microstructure contained 75-100 nm Pr1Co5 hard magnetic grains, 75-100 nm Pr1Co2 second phases, and < 10 nm TiC grain boundary prec ipitates. The important factors in achieving optimum loop shapes in Pr-Co a lloys were examined in detail. (C) 2000 American Institute of Physics. [S00 21-8979(00)24608-2].