中温锌钙系磷化工艺在Q345钢防腐蚀中的应用

Application of Medium Temperature Zn-Ca Phosphating Process in Corrosion Protection of Q345 Steel

选取Q345钢为基体进行中温锌钙系磷化处理,在磷化液温度分别为50、55、60、65和70℃的条件下制备了5种锌钙系磷化膜。采用浸泡实验和电化学腐蚀实验,对5种磷化膜的耐蚀性进行评价,并与Q345钢的耐蚀性进行了比较。结果表明,在中性氯化钠溶液中,相比Q345钢,磷化膜的腐蚀程度较轻,磷化膜的腐蚀电位发生正移,腐蚀电流密度降低;温度对磷化膜的耐蚀性有不同程度的影响,随着温度从50℃升高到70℃,磷化膜的腐蚀电位先正移后负移,腐蚀电流密度先降低后升高;当温度为65℃时制备的磷化膜具有相对优异的耐蚀性。

Five different types of Zn-Ca phosphating films were prepared on Q345 steel at the temperature of 50℃,55℃,60℃,65℃and 70℃,respectively.The immersion test and electrochemical corrosion test were carried out to evaluate the corrosion resistance of these phosphating films,and the corrosion resistance of these phosphating films was compared with that of Q345 steel.The results showed that in neutral sodium chloride solution,the corrosion degree of phosphating films was lighter than that of Q345 steel.Compared with Q345 steel,the corrosion potential of phosphating films was positively shifted and the corrosion current density was decreased.The corrosion resistance of phosphating films was affected by the temperature.As the temperature was increased from 50℃to 70℃,the corrosion potential of phosphating films first shift-ed positive and then negative,while the corrosion current density first decreased and then increased.The phosphating films prepared at 65℃exhibited relatively excellent corrosion resistance.