Abstract:
A sol-gel method was applied to prepare ZrO
2 and Al
2O
3 coatings on stainless steel(SS304) substrates and to seal the anodic oxidation films of an aluminum alloy. The high-temperature oxidation resistance of as-prepared ZrO
2 and Al
2O
3 coatings was investigated by cyclic high-temperature oxidation tests. The corrosion resistance of the sealed anodic films was investigated by electrochemical impedance spectroscopy(EIS) and exfoliation corrosion method. The experimental results indicate that the high-temperature oxidation resistance of the ZrO
2 and Al
2O
3 coatings is improved with the increasing of coating thickness,and the corrosion resistance of the sealed anodic films is also improved with the increasing times of sealing processes. However,the impedance value and corrosion degree of the sealed anodic films change slightly after more than 8 times of sealing processes. The corrosion resistance of the anodic films sealed with Al
2O
3 sol performs a little better than those with ZrO
2 sol with the same times of sealing processes.