X70钢在不同土壤环境中的交流腐蚀行为研究

Effects of AC on corrosion behavior of X70 steel in different soil environments

通过交流腐蚀模拟试验考察了X70钢在哈密、高钙镁、格尔木和鹰潭四种土壤模拟环境中的交流腐蚀规律,对腐蚀速率和极化曲线进行了电化学测试,并对腐蚀产物进行了微观形貌观察和成分分析。结果表明:在四种土壤环境中施加交流干扰后,X70钢的腐蚀速率v_(d)增大,其变化规律为v_(d高钙镁)<v_(d哈密)<v_(d鹰潭)<v_(d格尔木),在高钙镁土壤环境中生成的腐蚀产物比较致密,能对基体产生一定的保护作用,而在其他三种土壤环境中生成的腐蚀产物则比较疏松,不具备保护性。在四种土壤环境中施加交流干扰后,极化曲线均向右下方偏移,腐蚀电位发生负向偏移,腐蚀电流密度增大;在电化学阻抗谱测试中,施加交流干扰后,哈密、高钙镁和格尔木三种土壤环境中的电荷转移电阻均减小,从而减小了电化学反应阻力,加速了金属腐蚀。

The corrosion behavior of X70 steel in Hami soil,high calcium and magnesium soil,Golmud soil and Yingtan soil was investigated by AC corrosion simulation test.The corrosion rate and polarization curve were tested by electrochemical method,and the corrosion products were measured by microscopic morphology and composition analysis.The results showed the corrosion rate(v_(d))of X70 steel increased after application of AC interference,and the order of corrosion rate was v d(high calcium and magnesium soil)<v_(d(Hami))<v_(d(Yingtan))<v_(d(Golmud)),because corrosion products generated in high calcium and magnesium soil environment were relatively dense to provide protection for the steel,while the corrosion products generated in the other three soil environments were relatively loose and cannot protect steel against corrosion.After AC interference was applied in four soil environments,the polarization curves moved downward to the right,the corrosion potential shifted negatively,and the corrosion current density was intensified.In the electrochemical impedance spectroscopy test,the charge transfer resistance of X70 steel in Hami soil,high calcium and magnesium soil and Golmud soil was reduced which indicated AC interference can decrease the reaction resistance and accelerate the metal corrosion.