For aircraft serving in coastal environments, the aluminum alloy skin is exposed to high temperature, humidity, and salt environment for a long time. Pitting and exfoliation will affect its normal service life. In this article, static salt spray experiments and electrochemical tests were carried out on 2198-T8 Al–Li alloy in nine different corrosive environments. The effects of salt concentration, temperature, and humidity on the corrosion behavior were analyzed and compared. The relationship between corrosion environment parameters and pits was established. The results show that, under the same corrosion environment, the length, width, and depth of the pits all follow the log-normal distribution; compared with the salt concentration and humidity, the increase in temperature has the most obvious promotion on the corrosion rate. Based on the frequency statistics of pit size and electrochemical test results, the pit morphology was simplified to a semiellipsoid geometric model, and the pit size in different corrosive environments was predicted. The predicted size data all fall within the 1.5-fold dispersion region.

中文翻译：

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复杂腐蚀环境下凹坑的形态特征及几何预测模型

对于在沿海环境服役的飞机，铝合金蒙皮长期暴露在高温、潮湿、盐分环境下。点蚀、剥落会影响其正常使用寿命。本文对2198-T8铝锂合金在9种不同腐蚀环境下进行了静态盐雾实验和电化学测试。分析比较了盐浓度、温度和湿度对腐蚀行为的影响。建立了腐蚀环境参数与凹坑之间的关系。结果表明，在相同的腐蚀环境下，凹坑的长度、宽度和深度均服从对数正态分布；与盐浓度和湿度相比，温度的升高对腐蚀速率的促进最为明显。根据凹坑尺寸的频率统计和电化学测试结果，将凹坑形貌简化为半椭球几何模型，并预测了不同腐蚀环境下的凹坑尺寸。预测的尺寸数据均落在1.5倍离散区域内。