STRUCTURE AND HARD MAGNETIC PROPERTIES OF RAPIDLY QUENCHED Sm-Co-B ALLOY RIBBONS.

The hard magnetic properties of the Co-B ternary alloy ribbons in the composition range, 9 less than Sm(at%) less than 16, 2 less than B(at%) less than 5, bal. Co, were examined. The dependence of //iH//c and (BH)//m//a//x on the fabrication conditions and the concentration were clarified. The maximum value of (BH)//m//a//x for the ternary alloys, 8 MGOe, was obtained for ribbons with a concentration of approximately 12 at% Sm, 4 at% B, bal. Co. Addition of B to the Sm-Co binary alloy ribbons was found to be effective in increasing //iH//c in the Sm concentration range between 9 and 12 at%. Structural analysis revealed that the ribbons whose hard magnetic properties were improved by the addition of B consist of two phases, namely a Sm//2Co//1//4B phase and the high-temperature Sm//2 Co//1//7 phase. The ribbons which show the maximum values of (BH)//m//a//x consist of fine spherical grain particles (0. 2 to approx. 0. 3- mu m in diameter). The effect of the addition of B on the hard magnetic properties and also on the structure are discussed.