Effect of KH-570/SiO₂ Ratio on Corrosion Resistance of Al₂O₃-13% TiO₂ Seal Coating in Acid Environment

Aimed at some disadvantages of conventional sealing agents used in acid environment,in order to broaden the application of plasma spray coatings in some aggressive environments,a sort of novel KH-570/SiO2 hybrid sealing agent was prepared by Sol-Gel method and sealed on the surface of plasma sprayed Al2O3-13% TiO2 coating.The effect of the content of KH-570 on corrosion resistance of the coating in acid environment was studied.The results revealed that the KH-570 hybrid material was a good candidate as a sealing agent for plasma sprayed coating,which could improve efficiently corrosion resistance of the sealed coating in acid environment.The corrosion resistance of the coatings increased and then decreased with increasing additions of KH-570.When the volume ratio of TEOS to KH-570 additions was 4∶5,the sealed coating had the best corrosion resistance in acid environment,its corrosion potential increased 61.6% than that of the unsealed coating,and the corrosion current was only 1/1767 of that of the unsealed one.