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通过青岛大气暴露实验,对比了未处理和经硫硼酸阳极化处理的7050铝合金在典型工业海洋大气环境中的腐蚀行为。采用失重法获得腐蚀速率;使用扫描电镜对腐蚀产物进行微观形貌观察;使用EDS和XRD对腐蚀产物进行元素分析和相组成分析;运用电化学阻抗法对腐蚀产物层及氧化膜层的保护作用进行分析。结果表明:未处理的7050铝合金暴露2 a后,产生了大面积的剥蚀,腐蚀产物主要为Al(HSO_4)_3·6H_2O,Al_4SO_4(OH)10·5H_2O和NaAlSi_3O_8。硫硼酸阳极化处理的7050铝合金在青岛大气中暴露2 a后,局部出现点蚀,氧化膜对基体仍有良好的保护作用。硫硼酸阳极氧化预处理可以大幅度提高7050铝合金的耐蚀性。
Through the experiment of air exposure in Qingdao, the corrosion behavior of untreated and thioborate anodized 7050 aluminum alloy in typical industrial marine atmosphere was compared. The corrosion rate was obtained by weight loss method. The microstructure of corrosion products was observed by scanning electron microscope. The corrosion products were analyzed by elemental analysis and phase composition using EDS and XRD. The electrochemical impedance spectroscopy Analyze. The results showed that the untreated 7050 aluminum alloy exposed to large scale after 2 years of exposure. The corrosion products were Al (HSO 4) 3 · 6H 2 O, Al 4 SO 4 (OH) 10 5H 2 O and NaAlSi 3 O 8. Thioborate anodized 7050 aluminum alloy in Qingdao atmosphere exposed 2 a, local pitting corrosion, the oxide film is still a good substrate protection. Thioborate anodizing pretreatment can greatly improve the corrosion resistance of 7050 aluminum alloy.