Improving corrosion resistance of carbonyl iron powders by plasma electrolytic deposition

A coating was prepared on the carbonyl iron powders by plasma electrolytic deposition to improve its corrosion resistance. SiO₂ was uniformly coated with the thickness of ~10 nm. The composite powders exhibited superior corrosion resistance in both the NaCl and HCl solutions. The formation of the coating was the result of the electro-chemical absorption and reaction in the electrical field. The aqueous plasma had an important role in activating the surface and optimizing the microstructure of the coating. The superior corrosion resistance makes it available to be used in special environments and has greatly expanded its application fields.