NaCl对Q235钢早期腐蚀行为的影响

在实验室模拟了NaCl对Q235钢早期腐蚀的影响,研究了NaCl含量和浸泡时间对Q235钢腐蚀行为的影响。结果表明:试验条件下,当NaCl质量分数为3.5%时,Q235钢腐蚀倾向最大,电极表面的反应电阻最小,腐蚀速率最快;Q235钢的腐蚀电流密度和表面反应电阻随浸泡时间变化而出现波动,浸泡24 h后,腐蚀体系的自腐蚀电位最负,自腐蚀电流密度最大,腐蚀速率最快;电极表面的腐蚀产物对基体具有一定的保护作用,然而腐蚀产物较疏松,在电极表面的附着力小,很容易脱落而使腐蚀反应加快。

Effect of NaCl on Initial Corrosion Behavior of Q235 Steel

The effect of NaCl concentration and immersion time on the initial corrosion of Q235 steel was studied in laboratory.The results indicate that the critical corrosion concentration of NaCl was 3.5 wt％ under the testing conditions.In 3.5 wt％ NaCl solution,Q235 steel was more prone to corrosion and the corrosion rate was the largest,and the reaction resistance on the electrode surface was the least.Corrosion current density and surface reaction resistance of Q235 steel fluctuated with time.After 24 hours' immersion in 3.5 wt ％ NaCl solution,the free-corrosion potential in the corrosion system was the lowest,the corrosion current density and corrosion rate were the largest.Corrosion products on electrode surface had a limited protective effect on the substrate.Loose structure and small adhesion of the corrosion product made it easy to fall off from the electrode surface,and thus the corrosion reaction was accelerated.