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采用恒电位极化及三维视频显微技术研究不同pH值对304不锈钢在3.5%NaCl溶液中单个蚀孔的点蚀动力学及腐蚀形貌特征的影响。结果表明,当pH值等于1,4,7,10和14,极化电位为0.15VvsSCE时,单个蚀孔的点蚀电流、蚀孔体积、深度及孔口直径的增加速率随pH值的降低而增大。在同一pH值下,孔深的增加速率随时间的延长而增大,孔口直径的增加速率随时间的延长而减小。不同pH值下,单个蚀孔的生长均受腐蚀产物扩散控制。蚀孔表面为多孔花边盖,并且花边盖板的完整度随pH值的降低而下降。
The effects of different pH values on the pitting kinetics and corrosion morphology of 304 stainless steel in 3.5% NaCl solution were investigated by potentiostatic polarization and three-dimensional video microscopy. The results show that when the pH value is equal to 1, 4, 7, 10 and 14 and the polarization potential is 0.15 V vs SCE, the increase rate of pitting current, pore volume, depth and orifice diameter of single pits decreases with the decrease of pH value Increase. At the same pH, the increasing rate of pore depth increases with time, and the rate of increase of orifice diameter decreases with time. At different pH values, the growth of individual pits is controlled by the diffusion of corrosion products. The etched hole surface is a perforated lace cover, and the integrity of the lace cover decreases with decreasing pH.