304 L不锈钢焊缝在混凝土模拟孔隙液中的点蚀行为

采用动电位极化曲线、电化学阻抗谱、Mott-Schottky曲线等电化学方法研究了以308 L为焊丝的304 L不锈钢焊接接头在不同氯离子含量的混凝土模拟孔隙液中腐蚀行为和电化学规律。随Cl-增加,304 L不锈钢焊接接头的三个区域(母材、焊缝和热影响区)在混凝土模拟孔隙液中的自腐蚀电位、点蚀电位及电荷转移电阻降低,钝化膜中载流子密度和焊接接头的点蚀坑数量增加。在同浓度的腐蚀溶液中,308 L的焊缝区域耐蚀性最佳,热影响区次之,304 L基体表现出低的电荷转移电阻和高的掺杂浓度使得母材的耐蚀性最差。

Pitting corrosion of 304 L stainless steel welds in simulated concrete pore solutions

The pitting corrosion of 304 L austenitic stainless steel joints with 308 L austenitic stainless steel as welding sticks was investigated in simulated concrete pore solutions with different chloride ion concentrations by potentiodynamic polarization curves, electrochemical impedance spectroscopy and Mott-Schottky curves. It is found that chloride ions play an important role in the corrosion behavior of the joints. When the chloride ion concentration increases, the corrosion potential, breakdown potential and charge transfer resistance of the joints at three different weld zones, i. e. , base metal ( BM) , weld metal ( WM) and heat affected zone ( HAZ) , in the simulated solutions decrease, but the charge carrier density and the number of pitting sites in the joints increase. In the same simu-lated solution, the weld metal shows a better corrosion resistance, followed by the heat affected zone, and the base metal has the lowest corrosion resistance due to its much lower charge transfer resistance and higher doping content.