Magnetic properties of Co-Al melt-spun ribbons

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 1.6 kOe with a high saturation magnetization of 45 emu/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 20 kOe during annealing promotes the formation of the fcc-Co phase and results in the increase in the remanence value. (C) 2006 American Institute of Physics.