微弧氧化对7050铝合金腐蚀行为的影响

Microarc oxidation coatings and corrosion behavior of 7050 aluminum alloy

采用微弧氧化(MAO)技术在7050铝合金表面制备了陶瓷膜层,运用扫描电子显微镜(SEM)和能谱分析仪(EDS)表征陶瓷膜微观结构,采用动电位极化曲线、电化学阻抗谱(EIS)和慢应变速率拉伸试验(SSRT)研究了微弧氧化膜对7050铝合金在3.5%(质量分数)Na Cl水溶液中腐蚀和应力腐蚀开裂(SCC)行为的影响.结果表明:微弧氧化膜层由表面疏松层与内部致密层组成,表面疏松层主要由Al2O3组成,内部致密层由氧化铝与铝烧结而成.微弧氧化膜层可以有效抑制7050铝合金表面的腐蚀萌生及明显降低腐蚀速率,且使7050铝合金的应力腐蚀敏感性出现显著下降.

Ceramic coatings were formed on 7050 aluminum alloy（AA7050） by microarc oxidation（MAO）. Subsequently,scanning electron microscopy（SEM） and energy-dispersive spectrometry（EDS） were used to evaluate the microstructure of the coatings. The coatings consist of an outer porous layer made of Al2 O3 and an inner dense layer made of sintered alumina and aluminum substrate. Furthermore,potentiodynamic polarization tests and electrochemical impedance spectroscopy（EIS） were combined with slow strain rate tests（SSRT） to investigate the effect of microarc oxidation on the corrosion and stress corrosion cracking（SCC） of AA7050 in 3. 5% Na Cl solution. The corrosion on the surface of AA7050 and the corrosion rate and SCC decrease owing to the coatings on AA7050.