Characterization of Black Ceramic Coating Layer Produced on Al Alloy byn Plasma Electrolytic Oxidation in Alkaline Silicate Based Solution

摘要

The black ceramic coating layer was successfully prepared by plasma electrolytic oxidation (PEO) with electrolytes containing sodium tungstate (Na2WO4). Different gradients of black color were obtained with sodium tungstate concentrations in the electrolyte. Black colorization of PEO coating was not realized without sodium silicate (Na2SiO3) in the electrolyte. The corrosion current density of black ceramic coating layer was increased as compared to that of PEO coating produced without Na2WO4, s