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采用电化学技术(动电位极化曲线,自腐蚀电位,EIS,Mott-Schottcky(MS)曲线及循环伏安曲线)和表面分析方法(SEM和原位Raman光谱)研究了空冷20SiMn钢在pH值均为10.64的3种浓度的碳酸盐缓冲液和浓度恒定为0.437×10-3mol/L的NaOH溶液中的腐蚀行为.结果表明,20SiMn钢在NaOH溶液中发生了均匀腐蚀,经Fe(OH)2转变为最终产物a-Fe2O3和g-FeOOH;在低浓度碳酸盐缓冲液中发生了局部腐蚀,经绿锈GRs得到最终腐蚀产物a-Fe2O3和bFeOOH;在高浓度碳酸盐缓冲液中发生了钝化,并且受可溶性离子Fe(CO3)22-的影响,钝化膜的耐蚀性随碳酸盐总浓度的升高存在极值.
Electrochemical techniques (potentiodynamic polarization curve, self-corrosion potential, EIS, Mott-Schottcky (MS) curve and cyclic voltammetry) and surface analysis (SEM and in situ Raman spectroscopy) The results showed that the corrosion of 20SiMn steel in NaOH solution was uniform and the corrosion rate of Fe (OH) 2 ) 2 was transformed into the final products a-Fe2O3 and g-FeOOH; local corrosion occurred in the low concentration of carbonate buffer, the final corrosion products a-Fe2O3 and bFeOOH were obtained by the green rust GRs; in high concentration of carbonate buffer Passivation occurs, and the soluble ion Fe (CO3) 22- influence corrosion resistance of the passivation film with the total concentration of carbonate there is an extreme value.