The Influence of Current Density and Frequency on the Microstructure and Corrosion Behavior of Plasma Electrolytic Oxidation Coatings on Ti6Al4V

摘要

The effect of processing current density and frequency on the microstructure and corrosion behavior of the PEO coatings was studied. Coatings were characterized using FESEM, EDS, potentiodynamic polarization and EIS. The results indicated that the surface roughness, porosity and Al/Ti chemical value on the surface of the coatings increase with an increase in the current density and a decrease in the frequency of the PEO process. Corrosion investigations showed a relation between a mixed structural parameter (that contains thickness, porosity percentage and average pore diameter of the coatings) and the corrosion resistance of the PEO coatings. EIS data showed that higher coating thickness, lower surface porosity percentage and smaller pore diameter lead to the higher corrosion resistance.