Plasma-sprayed Al₂O₃-TiO₂ and Al₂O₃-TiO₂-Ta coatings were fabricated on aluminum substrates. Due to the introduction of tantalum, Al₂O₃-TiO₂-Ta coating surface morphology is more uniform and compact. At the same time tantalum metal has a very strong acid and alkali resistance, therefore, Al₂O₃-TiO₂-Ta coating relative to the Al₂O₃-TiO₂ coating has a stronger corrosion resistance. The results of Tafel curves show that the corrosion potential of Al₂O₃-TiO₂ coatings shifts the positive corrosion potential by 99.6 mV, and that of Al₂O₃-TiO₂-Ta coatings shifts the corrosion potential of Al by 208.9 mV. Therefore, the corrosion resistance of Al₂O₃-TiO₂ has been greatly enhanced due to the incorporation of Ta metal with high corrosion resistance. The Al₂O₃-TiO₂-Ta coating can effectively prevent the corrosion of the aluminum alloy.