Corrosion resistance and electrical conductivity of a nano ATO-doped MAO/methyltrimethoxysilane composite coating on magnesium alloy AZ31

An electrically conductive coating was prepared on micro-arc oxidized (MAO) Mg alloy AZ31 via antimony tin oxide (ATO) particles doping in methyltrimethoxysilane (MTMS) coating. A sandwich structure was observed as the ATO particles agglomerated at the top and bottom layers in the MTMS coating via field-emission scanning electron microscopy (FE-SEM). Electrochemical and hydrogen evolution tests revealed high corrosion resistance of the composite coating. Although the ATO-doped MAO/MTMS coating showed a low electrical conductivity, a conductive path was formed on the coating surface layer, enhancing the transfer of static charges. The formation and corrosion mechanisms of the composite coatings are proposed.