The Magnetic and Magnetostrictive Properties of Melt - Spun Ribbons of B Containing Terfenol-D Alloys

The magnetic and magnetostrictive properties of melt-spun ribbons of the alloys (R_(0.33)Fe_(0.67))_(1-x)Bx (R=Tb_(0.3)Dy_(0.7) and 0≤x≤0.06) are investigated as a function of wheel speed during melt-quenching. The saturation magnetization of the alloys with a crystalline phase ranges from 70 to 80 emu/g and does not vary substantially with the B content. The saturation magnetization of an amorphous phase, which is formed at the condition of high wheel speed and high B content, is reduced significantly, however. The coercive force is minimum at x=0.02 and increases monotonously with the further increase of B content when the microstructure mainly consists of a crystalline phase, but again it is reduced significantly by the formation of an amorphous phase. The low field sensitivity of magnetostriction with magnetic field is found to be good for the alloys with x≤0.04 over a wide range of wheel speed. This magnetostrictive behavior is in contrast with that observed previously for Dy-Fe and Tb-Fe based alloys and is thought to be due to low intrinsic magnetocrystalline anisotropy of the compound.