Study of Phosphate Coatings for Fe Based Soft Magnetic Composites

Inorganic phosphate coating was prepared on the surface of iron powders by chemical method.Powder metallurgy process was employed to obtain the soft magnetic composite(SMC)components by compacting and heat treating the powders.The particles were characterized by means of scanning electron microscopy(SEM),X-ray diffraction(XRD)and thermogravimetry-differential thermal analysis(TG-DTA).The results suggest that thermall stable phosphate coated iron powder can be prepared with chemical method.Resistive insulation of the coat may break down due to the crystallization of the amorphous phosphate coating at above 600℃ which needs to be proved through further resistivity tests.