根据点蚀成核机理和钢筋极化原理分别建立了点蚀电位（Epit）和自腐蚀电位（Ecorr）理论模型。基于腐蚀热力学，将临界氯离子含量（Ccrit）定义为两种电位相等时的氯离子含量，提出了临界氯离子含量理论模型。结果表明，点蚀电位与氯离子含量的对数负线性相关；氯离子含量增加导致阳极极化曲线负移，从而导致自腐蚀电位降低。临界氯离子含量随着自腐蚀电位、点蚀电位、温度和pH值的变化呈指数型变化，因而离散性较大。对于温度为298 K，pH为13.5的工况，临界氯离子含量（表征为[Cl-]/[OH-]）理论值为1.41。

Theoretical models for pitting potential (Epit) and self-corrosion potential (Ecorr) were established based on the pitting nucleation mechanism and steel polarization theory, respectively. Based on corrosion thermodynamics, the critical chloride content (Ccrit) was defined as the chloride content at which Epit is equal to Ecorr, and a theoretical model for Ccrit was proposed. The results indicate that Epit exhibits a negative linear correlation with the logarithm of chloride content. An increased chloride content decreases Ecorr by causing a negative shift in the anodic polarization curve. Ccrit varies exponentially with Epit, Ecorr, temperature and pH value, small variations in the four parameters can be magnified as large variability in Ccrit, which partly accounts for its significant scatter in the literature. For a typical temperature of 298 K and a pH value of 13.5, the benchmark value of Ccrit (expressed as [Cl-]/[OH-]) is 1.41.

TU528