Influence of Anodization Condition on Hydrophobicity, Morphology, and Corrosion Resistance of 17-4PH Stainless Steel

The anodization process was applied to 17-4PH stainless steel to modify its surface and to enhance hydrophobicity. The effects of various H2SO4/glycerin electrolytes and applied voltages on the water contact angle, the surface morphology (roughness), and corrosion resistance were investigated. It was observed that a high ratio of an H2SO4/glycerin electrolyte and high applied potentials resulted in an increase of a contact angle and an enhancement of the surface roughness. The highest contact angle was found to be up to 122.3°, when anodizing at 40 V using 70/30 of H2SO4/glycerin as electrolyte. Any further increase in the ratio of H2SO4/glycerin tended to reduce the contact angle. An electrochemical test showed that corrosion resistance was dependent on the hydrophobicity and surface roughness.