High coercivity of partially devitrified glass-coated finemet microwires: Effect of geometry and thermal treatment

The effect of annealing (at 300-700 degreesC) on coercivity of finemet-type Fe72.3+xCu1Nb3.1Si14.5-xB9.1 (x = 0 and 1.1) microwires has been studied. Strong magnetic hardening without deterioration of mechanical properties ha s been found at annealing temperatures around 500 degreesC for one of the s ample (a: = 0). The exact value of coercivity, H-c, and annealing temperatu re, T-ann, corresponding to such maximum of H-c depend on the sample diamet er and the glass coating thickness (ratio rho = d/D). Observed dependencies have been interpreted in terms of effect of magnetoelastic anisotropy in p artially devitrified two-phase samples.