CORROSION BEHAVIOR OF CERIUM-BASED CONVERSION COATINGS ON MAGNESIUM ALLOYS EXPOSED TO AMBIENT CONDITIONS

摘要

Exposure of CeCCs on AZ31B and AZ91D Mg alloys to ambientsunlight, temperature, and humidity was done to determine theeffect on corrosion resistance. It was found that the CeCCschanged from pale yellow to almost translucent after 24 hours ofsunlight exposure. The effect of the solar electromagneticradiation on the morphological, chemical and optical properties ofthese coatings was investigated using SEM and UV-Vischaracterization techniques. In addition, the corrosionperformance of CeCCs before and after ambient exposure wasstudied by ASTM B117 neutral spray testing and electrochemicalpolarization measurements. In general, the changes in appearancedid not adversely affect the corrosion performance of the coatings.