酸性介质中HR-2不锈钢表面活性的SECM三维图像表征研究

Surface Activity of HR-2 Stainless Steel in Acid Solution with SECM

采用扫描电化学显微镜(SECM),面扫描与线性扫描技术相结合,研究了HR-2不锈钢在0.5 mol/LH_2SO_4+0.1 mol/L NaCl溶液中的腐蚀行为。结果表明:HR-2不锈钢在该溶液中的开路电位、活化电位及钝化区电位分别为:-0.4V、-0.23V、0.0V～0.8V,基底保持开路电位和活化电位时,探头最大电流为9.5 nA和35.2 nA,基底形成钝化膜后探头电流明显减小;当探头电位为-0.2V时能有效氧化基底产生的H_2,0.6V时能有效氧化基底反应产生的Fe^(2+),探头-基底间距为20μm时,可较好地表征基底活性;当溶液中硫脲浓度为0.75 mmol/L时,有最佳的缓蚀作用。

By surface scanning technology and linear scanning technology with SECM, which have a micrometer pixel, corrosion behavior of HR-2 stainless steel in 0.5 mol/L H2SO4＋0.1 mol/L NaCl solution was studied. The results show that： open circuit potential, activation potential, and passivation potential are -0.4 V, -0.23 V, 0.0 V - 0.8 V relatively. The maximum current of probe is 9.5 nA when substrate current is open circuit potential 35.2nA, when substrate current is activation potential. When passive film formed on the substrate, the current of probe largely decreased. H2 was obtained when current of probe is-0.2 V, Fe2＋ was obtained when current of probe is 0.6 V. It is also observed that the proper distance between probe and substrate is 20 μm, and best concentration of the corrosion inhibition （sulfocarbamide） is 0.75 mmol/L.