Effect of surfactants on surface morphology of ceramic coatings fabricated on magnesium alloys by micro-arc oxidation

Ceramic coatings fabricated by micro-arc oxidation generally possess a foam-like structure with high bulk porosity which restricts them from even wider technical application. Based on interfacial tension modifying theory, different surfactants are added into the electrolyte to inhibit the generation of pores within ceramic coatings. The results indicate that surfactants influence strongly the morphology of ceramic coatings and play an essential role to fabricate a ceramic coating with low porosity. Once surfactants are added into the solution, all the coatings exhibit almost identical morphology and reveal a considerable decrease of pores' number.