Magnetic properties of Co–Al melt-spun ribbons

Abstract

Co – Al alloy ribbons were produced by melt spinning followed by heat treatment. Although the Co–Al melt-spun ribbons had low coercivities, annealing of the ribbons resulted in an increase in the coercivity. The optimally annealed Co75Al25 melt-spun ribbon exhibited a high coercivity of 1.6kOe with a high saturation magnetization of 45emu∕g. The annealed Co75Al25 melt-spun ribbon consisted of the hcp-Co and CoAl phases together with a small amount of the fcc-Co phase. It was found that the application of a magnetic field of 20kOe during annealing promotes the formation of the fcc-Co phase and results in the increase in the remanence value.