模拟硫酸型酸雨作用下酸性土壤中不锈钢腐蚀电化学行为的研究

CORROSION BEHAVIOUR OF STAINLESS STEEL IN ACID SOIL WITH A SIMULATED SULFURIC ACID RAINFALL

采用线性极化、Tafel曲线及电化学交流阻抗等方法,研究了酸性土壤中pH=1模拟硫酸型酸雨对316L不锈钢腐蚀电化学行为的影响.结果表明:淋溶蒸馏水不锈钢试样的Rp值先升高后降低,腐蚀电流先增大后减小后又缓慢增大,淋溶模拟硫酸型酸雨不锈钢试样的Rp值先升高后降低再升高,腐蚀电流先减小后缓慢增大;EIS表明:两种情况下都出现了两个容抗弧,但淋溶模拟酸雨试样的高频区表现为一不完整容抗弧.

An acid soil induced corrosion of 316L stainless steel in a simulated sulfuric acid rainfall of pH = 1 was investigated by linear polarization curve, Tafel curve and electrochemical impedance spectroscopy （EIS）. Linear polarization curves reveal that in the acid soil Rp of 316L steel in a rainfall of distilled water increases at the initial stage and then decreases,however,Rp of 316L steel in the simulated acid rainfall increased at the initial stage, then decreases and finally increases again. Tafel curves show that Icorr of 316L steel in the acid soil with the rainfall of distilled water increases at the initial stage,then decreases and increases slowly finally, but Icorr of 316L steel in the acid soil with the simulated acid rainfall decreased at the initial stage and then increases slowly. Electrochemical impedance diagram of 316L steel in the acid soil with rainfall of distilled water shows two capacitive loops and it in the acid soil with simulated acid rainfall exhibits two capacitive loops, but the one at high frequency regions is an uncompleted loon.