超声喷丸稀土预制膜对铝合金微弧氧化耐蚀性的影响

Effect of the Ultrasonic Shot Peening-rare Earth Precursor Films on the Corrosion of Micro Arc Oxidation of Aluminum Alloy AC7A

对AC7A铝合金表面进行超声喷丸-稀土硝酸钇预处理制备出预制膜层,采用恒电流控制模式在Na_2SiO_3电解液中制得Ac7A铝合金微弧氧化陶瓷层,通过扫描电镜观察陶瓷膜的表面形貌,采用X-射线衍射仪分析膜层的相结构,利用电化学测试评价了陶瓷膜的耐蚀性能。结果表明,AC7A铝合金表面微弧氧化陶瓷层主要由α-Al_2O_3和γ-Al_2O_3相组成,经过预处理后表面微孔数明显下降,表面更加平整,与单纯的微弧氧化陶瓷膜层相比,超声喷丸-稀土硝酸钇预处理后的微弧氧化陶瓷层的耐蚀性得到了很大的提升。

The surface of AC7 A aluminum alloy was pretreated by ultrasonic shot peening-rare earth yttrium nitrate and prefabricated into films.The ceramic coatings on AC7 A aluminum alloy were fabricated by micro-arc oxidation（MAO） in silicate electrolyte.The morphology,phase composition,element distributing and corrosion resistance were examined by scanning electron microscope（SEM）,X-ray diffraction（XRD）,energy dispersive spectroscopy（EDS） and tafel plot.The results show that the MAO coatings are composed of α-Al_2O_3 and-γ-Al_2O_3.This method improved the surface morphology of the micro-arc oxidation ceramic coating of AC7 A aluminum alloy as well as its corrosion resistance.