304不锈钢在模拟混凝土孔隙液中的点蚀行为研究

Pitting Corrosion Behavior of 304 Stainless Steel in Simulated Concrete Pore Solutions

采用电化学测试方法研究了不同Cl-浓度下,304不锈钢在两种模拟混凝土孔隙液中的点蚀行为,确定了304不锈钢的临界Cl-浓度;采用SEM观察了304不锈钢表面钝化膜在临界Cl-浓度前后的状态。结果表明,通过动电位极化和恒电位阻抗方法确定了304不锈钢的临界Cl-浓度,且数值基本一致,并SEM观测结果相一致;而开路电位下的阻抗测试并不能确定临界Cl-浓度。

The pitting corrosion behavior of 304 stainless steel in two simulated concrete pore solutions with different chloride ion concentrations was assessed via electrochemical measurement methods and SEM,in terms of the critical chloride ion concentration for pitting initiation and surface morphology before and after test of 304 stainless steel.The results showed that the critical chloride ion concentration of 304 stainless steel determined by potentiodynamic polarization and potentiostatic electrochemical impedance spectrum in saturated Ca(OH)2 and HCO_(3)-/CO_(3)2-solutions were basically consistent.The SEM test results also confirmed the above conclusion.The electrochemical impedance acquired form open circuit potential measurement could not reveal the critical chloride concentration.