Characterization of surface oxide layer of iron particles for magnetic recording II. Surface oxide layer of further oxidized iron particles in high humidity

The surface oxide layer of additionally oxidized iron particles for magnetic recording in high humidity (90%) and at 60°C was examined by Mossbauer spectrometry. The mechanism of deterioration was concluded to begin with oxidation: the deterioration of the saturation magnetization (Is) of iron particles was caused by a deterioration of the Is of the surface oxide layer; later deterioration was caused by an increase in the amount of the oxide layer. The specific gravity of the surface oxide layer became gradually reduced during the oxidation.