氧化铝涂层在熔融锌液中的腐蚀及热震行为

Corrosion and thermal shock behavior of Al_2O_3 ceramic coating in molten zinc

为了分析陶瓷涂层的失效机制,将带有陶瓷涂层的试件放入到锌液中进行腐蚀,并与热震后的涂层试件进行比较.通过电镜照片的微观分析及x-射线衍射分析得出,腐蚀后涂层与锌液界面处生成了锌铝氧三元化合物ZnO.A l2O3、3ZnO.47A l2O3、4ZnO.11A l2O3等,热震后的试件则出现涂层开裂及脱落现象.对比腐蚀试验和热震试验说明,陶瓷涂层在锌液中腐蚀不足以使涂层发生失效,而热震后发生涂层开裂进而使锌液进入涂层内部直接与基体接触会造成涂层失效.

In order to analyze the failure mechanism of Al2O3 ceramic coating, the corrosion experiment was carried out through submersing the coating into molten zinc, and the result was compared with that of the coating subjected to thermal shock. The SEM and XRD analysis reveals that some compounds such as ZnO.Al2O3, 3ZnO.47Al2O3 and 4ZnO. 11Al2O3 form at the interface of coating and molten zinc after corrosion test, and the coating subjected to thermal shock may break and peel off. It is found by comparing the results of the corrosion and thermal shock experiments that the main failure mechanism of the coatings is not the surface corrosion of the coating in molten zinc. The cracking of the coating after thermal shock will lead to the direct contact of molten zinc and substrate metal, and thus the failure of the coating occurs.