AN EXPERIMENTAL INVESTIGATION OF STRUCTURE OF SOME INTERNALLY OXIDISED FERROMAGNETIC ALLOYS

Results are presented of optical, scanning electron and transmission electron microscope observations on some internally oxidised ferromagnetic alloys. The alloys investigated were of nominal composition 0.058 wt % Si in Ni, 0.48 wt % Si in Ni and 0.17 wt % Si in Co 66.2%-Ni 33.7%. The alloys were in polycrystalline form and in addition single crystals of 0.058 wt % Si in Ni were examined. The diffusion and oxidation rate constants are calculated and the state of the oxide product as a function of (i) depth in the alloy, (ii) oxidising temperature and (iii) alloy composition is considered. The possibility of using such systems as device material and as test material for theories of coercivity and approach to magnetic saturation is considered. © 1969 Chapman and Hall.