Study on Al2O3 coating deposited on 2024 al alloys by micro arc oxidation (MAO) using TiO2 Nano additives

In this work, the effect of adding natural additives such as rice husks ash and nano additives such as TiO2 to the electrolyte on the properties of ceramic oxide coating formed on 2024 Al alloy substrate by micro arc oxidation (MAO). Results proved that the formation of hard ceramic oxide coatings were values(313 to 531.3)HV. Roughness increased with deposition time increasing, thickness of coatings variation with deposition time. Morphology of coated sample for 45min with electrolyte compositions(10g/l KH2PO4, 5g/l NaCO3, 4g/l H3PO4, 6g/l (NH3)2MO7O24,3g/l RHA, and 9g/l KOH, 1g/l nanoTiO2)showed the dense structure and uniform pores distribution, increasing the addition of TiO2to 3g/lthe results showed that more porous structure. Wear resistance of coatings improved by means of decreasing loss weight from (0.0017g of substrate) to (0.0003-0.0009)of samples at (15min and 60min) respectively, with composition(1g/l nanoTiO2, 10g/l KH2PO4, 5g/l NaCO3, 4g/l H3PO4,6g/l (NH3)2MO7O24,3g/l RHA, and 9g/l KOH) .