Hard magnetic phase in rapidly quenched Zr-Co-B alloys

In order to identify a hard magnetic phase in rapidly quenched Zr-Co-B alloys and clarify its magnetic properties, Zr-Co-B ribbons, Zr-Co ribbons, and Zr-Co ingots were studied. The hard magnetic phase is interpreted as a Zr/sub 2/Co/sub 11/ intermetallic compound. This compound has a Curie temperature of 500 degrees C and uniaxial magnetic anisotropy with an anisotropy field of 34 kOe. The magnetization of this compound was estimated to be 67 emu/g at 15 kOe. In addition to the hard magnetic phase, the low and high T/sub c/ phases appear in both binary and ternary alloys. The low T/sub c/ phase is FCC Zr/sub 6/Co/sub 23/ with T/sub c/=180 degrees C. The magnetization of Zr/sub 6/Co/sub 23/ was estimated to be 44 emu/g at 15 kOe. The high T/sub c/ phase is cobalt including a small amount of zirconium. In Zr-Co-B alloys, suitable boron addition is shown to enhance the coercive force. On the other hand, the addition increases the magnetization. While the boron addition produces cobalt, it reduces Zr/sub 6/Co/sub 23/ or quenches its ferromagnetism.>