论文部分内容阅读
通过交流腐蚀模拟实验考察了X70钢在4种环境介质中的交流腐蚀行为,获得了X70钢在4种介质中的腐蚀速率K_d。结果表明,腐蚀速率K_(d(NaCl))>K_(d(Na_2SO_4))>K_(d(CaCl_2))>K_(d(MgCl_2))。采用SEM、EDS和XRD对腐蚀产物膜的表面/截面微观形貌、元素和物相成分进行了表征与分析,探讨了X70钢在相同交流电流密度下,不同介质中腐蚀速率差异的原因:在Na_2SO_4和NaCl介质中,腐蚀产物膜比较疏松,侵蚀性离子SO_4~(2-)和Cl~-的存在会加速X70钢的腐蚀,Na~+不会影响腐蚀产物膜的形成;在MgCl_2和CaCl_2介质中,Ca~(2+)和Mg~(2+)的存在有利于形成保护性好的致密腐蚀产物膜。
The AC corrosion behavior of X70 steel in four kinds of environmental media was investigated by AC corrosion simulation experiment, and the corrosion rate K_d of X70 steel in four kinds of media was obtained. The results show that the corrosion rates are K_ (d (NaCl))> K_ (d_2 (Na_2SO_4))> K_ (dC (CaCl_2))> K_ (dCl_2). The surface / cross-section morphology, elemental and phase composition of corrosion products were characterized and analyzed by SEM, EDS and XRD. The reasons for the difference of corrosion rate of X70 steel in different media at the same AC current density were discussed: In Na_2SO_4 and NaCl media, the corrosion products were loose, the corrosion of X70 steel was accelerated by the presence of SO_4 ~ (2-) and Cl ~ - ions, and Na ~ + did not affect the formation of corrosion film. In MgCl_2 and CaCl_2 In the medium, the presence of Ca2 + and Mg2 + is conducive to the formation of a protective film of dense corrosion products.