采用失重试验以及电化学测试研究了A508III低合金钢在25 ℃下0.05~0.5 mol/L硼酸溶液中的腐蚀与电化学行为.A508III钢在高浓度硼酸溶液中开路电位低于-500 mV(SCE),对应低电化学阻抗和高腐蚀速率.A508III钢在低浓度硼酸溶液中的开路电位会出现三种状况:低于-500 mV、大于-200 mV和介于其间的中间电位,其中高开路电位对应高电化学阻抗,而低开路电位对应低电化学阻抗.A508III钢在所测试的几种硼酸溶液中的阳极极化曲线与阴极极化曲线均在较宽的电位范围内表现出电位-电流线性关系,与溶液的低电导率有关.开路电位值以及相应的腐蚀速率结果与电位-pH图计算结果一致.

The corrosion and electrochemical behavior of A508III low alloy steel in 0.05-0.5 mol/L H3BO3 solutions at 25 ℃ were studied by weight loss measurements and electrochemical measurements.Low open circuit potentials,low electrochemical impedance and high corrosion rates were observed in boric acid solutions of higher concentrations.Three levels of open circuit potentials,i.e.higher potentials (>-200 mV(SCE)),lower potentials (<-500 mV(SCE)),and intermediate potentials were observed in boric acid solutions of lower concentrations,where lower open circuit potentials corresponded to lower electrochemical impedance and higher open circuit potentials corresponded to higher electrochemical impedance.Anodic and cathodic polarization curves showed a linear relationship in a wide range of potential,which was related to the low conductivity of test solutions.The measured values of open circuit potentials,corrosion rates and the calculated E-pH diagrams were consistent.