Formation mechanism and surface characterization of ceramic composite coatings on pure titanium prepared by micro-arc oxidation in electrolytes containing nanoparticles

Abstract

Abstract The aim of this work is to study how nanoparticles incorporate into the prepared ceramic composite coatings on titanium by micro-arc oxidation (M.A.O.) technique in electrolytes containing nanoparticles and modify the surface characteristics. In order to achieve this goal, SiC and SiO 2 nanoparticles (as main and auxiliary particles, respectively) were added to aluminate based electrolytes and M.A.O. process was performed under constant voltage regime using a pulsed power supply. Finally, the effect of addition of nanoparticles on current-time responses, surface morphology, thickness, chemical and phase composition of coatings were investigated. The obtained results showed that addition of nanoparticles (7.5 g/l) to the electrolytes, had no effect on the current-time responses and coating thickness of samples. However it caused a reduction in the size of micro-pores and surface roughness of M.A.O. coatings. It was also concluded that nanoparticles incorporate into the coating with the aid of both electrophoretic force and micro-sparks.