The influence of Nano-TiO2 and Nano-Al2O3 Particles in Silicate Based Electrolytes on Microstructure and Mechanical Properties of Micro Arc Coated Ti6Al4V Alloy

Ceramic oxide coatings were fabricated on Ti6Al4V alloy by micro arc oxidation (MAO) in silicate electrolytes, with nano-TiO2 and nano-Al2O3 and without nano-additives. Effects of nano additives on the structural and mechanical properties of the MAO coatings were analysed. The MAO coatings were investigated by scanning electron microscopy (SEM), Energy-Dispersive spectroscopy (EDS) micro-hardness and linear wear test. Results show that the surface morphology and tribological properties of MAO coatings are greatly influenced by nano additives in electrolytes. After the coating treatment the surface hardness values increased from 300 HV0.1 to 635 HV0.1. The hardness tests show that nano-Al2O3 additition coating has higher microhardness values than those without any additives. The results indicated that TiO2 and Al2O3 nanoparticles into the coatings make harder and denser surface and increase the wear resistance. The wear resistance of the nano-TiO2 and nano-Al2O3 additives coatings was enhanced about 5 times than without nano additives coating.