Abstract：
A mechanistic model of atmospheric bimetallic corrosion with a simplified empirical approach to the onset of localized corrosion attacks is presented. The model was built for a typical bimetallic sample containing aluminum alloy 1050 and stainless steel 316L sheets. A strategy was developed that allowed the model to be calibrated against the measured galvanic current, geometrical corrosion attack properties, and corrosion products. The pitting-onset simplification sets all pits to be formed at a position near the nobler metal and treated all pits as being of the same shape and size. The position was based on the location of the highest pitting events and the pit attributes on an average of the deepest pits. For 5 h exposure at controlled RH (85%, 91%, and 97%) and salt load (86 μg NaCl/cm2), the model was shown to be promising: both for analysis of local bimetallic corrosion chemistry, such as pH and corrosion products, and for efficient assessment of pitting damage by computing a single largest pit depth. Parametric studies indicated that the pitting-onset approximation deviated the most at the beginning of exposure and when RH was below 91%.
摘要：
提出了一种大气双金属腐蚀的机理模型，该模型采用了简化的经验方法来解决局部腐蚀攻击。该模型是针对包含铝合金1050和不锈钢316L薄板的典型双金属样品建立的。开发了一种策略，可以根据测得的电流对模型进行校准，几何腐蚀侵蚀特性，和腐蚀产物。点蚀起始简化将所有凹坑设置为在较高金属附近的位置处形成,并且将所有凹坑处理为具有相同的形状和尺寸。该位置基于最高坑事件的位置和最深坑的平均坑属性。在受控RH下暴露5小时(85%，91%,和97%)和盐负荷(86μgNaCl/cm2)，该模型被证明是有前途的：既用于分析局部双金属腐蚀化学，如pH值和腐蚀产物，并通过计算单个最大凹坑深度来有效评估点蚀损伤。参数研究表明，点蚀发作近似值在暴露开始时和RH低于91％时偏差最大。
