表面粗糙度对304不锈钢早期点蚀行为影响的电化学方法

采用动电位扫描、电化学阻抗谱和电化学噪声等方法研究了4种不同表面粗糙度304不锈钢电极在质量分数为3％的NaCl溶液中的早期腐蚀行为.随着不锈钢电极表面粗糙度的下降,304不锈钢自腐蚀电位与点蚀电位均有所上升；电荷转移电阻噪声电阻明显升高,而电位标准偏差与电流标准偏差则有所降低；粗糙度0.25μm的电极在阻抗谱低频区出...

Effect of Surface Roughness on Initial Pitting Corrosion Behavior of 304 Stainless Steel

In 3% NaCl solution, the early stages of pitting corrosion of 304 stainless steel ground with different aluminum oxide water proof papers were studied by dynamic potential scanning, electrochemical impedance spectrum （EIS） method and electrochemical noise （EN） method. The results indicate that, with the decrease of surface roughness, the corrosion potential and pitting corrosion potential rose, the charge transfer resistance and the noise resistanc also rose obviously. The standard deviation of potential, as well as the standard deviation of current, decreased as the surface roughness decreased. A diffusion tail inclining along the angle of 45° to the x-axis was observed when the electrode with 0.25μm roughness was tested, indicating diffusion began at the surface. The results suggest that metastable pits initiate and grow up more difficultly at smooth surface than at rough surface.