Study of the origin of coercive force in semihard magnetic Co-Fe-Ni-alloys with additions of Al and Ti

Magnetic semihard Co-Fe-Ni-alloys with additions of aluminium and titanium were investigated by measurements of coercive force and magnetization as a function of aging and measuring temperature as well as by electron microscopy. The coercive force is due to the α and γ phase precipitates having shape anisotropy and different saturation magnetization. It is shown that for alloys with up to 30 wt.-% Co content the variation of the coercive force is predominantly determined by the term in the equation given by Stoner and Wohl-farth. For alloys with Co content more than 30% however the coercive force is mainly influenced by the shape anisotropy of the precipitates.