飞机用阳极氧化铝合金在醋酸钾型除冰液干湿交替作用下的腐蚀电化学行为研究

Research on the Corrosion Electrochemical Behavior of Anodized Aluminum Alloy for Aircraft Under the Action of Wet and Dry Alternation of Potassium Acetate Deicing Solution

在实验室模拟了除冰液对飞机蒙皮材料干湿交替腐蚀过程,采用宏观电化学和扫描开尔文探针(SKP)微区技术研究了飞机蒙皮用阳极氧化2024铝合金接触醋酸钾型飞机除冰液的腐蚀电化学行为。结果表明:未加缓蚀剂的除冰液浓度较高时腐蚀性强,对阳极氧化铝合金腐蚀较为严重;随除冰液浓度降低,腐蚀倾向和腐蚀速率减小。添加缓蚀剂后,高浓度除冰液由于缓蚀剂浓度在其最佳浓度范围,缓蚀效率高,阳极氧化铝合金的腐蚀非常轻微;随除冰液浓度降低,缓蚀剂浓度亦随之降低,缓蚀剂逐渐失效,除冰液的腐蚀性反而增强,阳极氧化铝合金的腐蚀倾向和腐蚀速率均随之增大。随腐蚀周期延长,试样在除冰液中的膜电阻呈波浪形逐渐增大趋势,电荷转移电阻则先减小后增大;除冰液腐蚀前后,阳极氧化铝合金表面SKP微区电位均呈随机分布,且随腐蚀周期延长随机变化,无明显点蚀发生,除冰液对阳极氧化铝合金的腐蚀为全面腐蚀。

The laboratory simulation of the wet and dry alternating corrosion process of aircraft skin material by deicing fluid is conducted.The corrosion electrochemical behavior of anodized aluminum alloy for aircraft skin material contacting with potassium acetate deicing solution is studied by macro-electrochemical techniques and scanning Kelvin probe(SKP)micro-area technology.The results show that at a high deicing fluid concentration and without corrosion inhibitor,the corrosion rate of the anodize 2024 aluminum alloy is very high,but the destruction on the metal surface reduce when the concentration of the deicing fluid decrease.The addition of a corrosion inhibitor to the deicing fluid at high concentration led to a high corrosion inhibition efficiency,and a resultantly minimal damage to the anodize aluminum alloy.Because the high concentration deicing solution is in an optimal concentration range.Decreasing the concentrations of the deicing fluid and the corrosion inhibitor caused a gradual loss of inhibition efficiency.Electrochemical Impedance Spectroscopy(EIS)measurements show that the film resistance of the anodized aluminum alloy increases up and down with the corrosion cycle while the charge transfer resistance decreases first and then increase.The SKP test on the anodize aluminum alloy before and after exposure to the deicing solution that the micro-area potential on the surface of the metal is randomly distribute,and dependent on the corrosion cycle.There is no obvious pit formation on the surface of the anodize aluminum alloy,therefore the corrosion is general corrosion.