Effects of nano-additive TiO2 on performance of micro-arc oxidation coatings formed on 6063 aluminum alloy

Ceramic coatings were fabricated on aluminum alloy substrates by micro-arc oxidation (MAO) in silicate electrolytes doped with different concentrations of TiO2 nano-additive. Effects of nano-additive concentration on the structural and mechanical properties of the MAO coatings were analyzed. The results revealed that some nano-particle were incorporated into the resulting coating during the MAO process, while there was a reasonable concentration for the TiO2 nano-additive. With increasing the nano-additive concentration to 3.2 g/L, the adhesion value increased, while mean friction coefficient and mass loss decreased. A further increase of nano-additive deteriorated the adhesion and mean friction coefficient values, which was consistent with the micro-hardness tests.