封闭处理对超声波辅助制备的锌系磷化膜耐蚀性的影响  

Effect of sealing treatment on corrosion resistance of zinc phosphating film prepared under ultrasonic condition

作　　者：贾春燕[1] 刘海涛 Jia Chunyan;Liu Haitao(Yellow River Conservancy Technical Institute,Kaifeng 475004,China;Henan Polytechnic University,Jiaozuo 454003,China)

机构地区：[1]黄河水利职业技术学院,河南开封475004 [2]河南理工大学,河南焦作454003

出　　处：《电镀与精饰》2024年第9期48-55,共8页Plating & Finishing

基　　金：河南省自然科学基金项目(182300410200)。

摘　　要：在Q345钢磷化过程中引入超声波以改善锌系磷化膜表面平整度和致密性,为进一步提高超声波辅助制备的锌系磷化膜耐蚀性,分别采用油性封闭剂、硝酸铈溶液、硅酸钠溶液进行封闭处理。结果表明:硅酸钠溶液的封闭效果好于油性封闭剂和硝酸铈溶液,封闭后超声锌系磷化膜的物相组成为Zn_(3)(PO_(4))_(2)·4H_(2)O、Zn_(2)Fe(PO_(4))_(2)·4H_(2)O、ZnSiO_(3)和Na_(2)Si O_(3),并且呈现良好的致密性和耐蚀性,其耐硫酸铜点滴时间超过150 s,腐蚀电流密度低至3.20×10^(-6)A/cm^(2),较未封闭超声锌系磷化膜的腐蚀电流密度降低幅度接近一个数量级。在硅酸钠溶液封闭过程中发生腐蚀整平现象,同时生成ZnSiO_(3)并析出Na_(2)Si O_(3)起到填补孔隙的作用,使超声锌系磷化膜的致密性得到更大程度改善,从而显著增强抗腐蚀能力。Ultrasonic was introduced in the phosphating process of Q345 steel to improve the surface flatness and compactness of zinc phosphating film.In order to further improve the corrosion resistance of zinc phosphating film prepared under ultrasonic condition,oil sealing agent,cerium nitrate solution and sodium silicate solution were used for sealing treatment respectively.The results show that the sealing effect of sodium silicate solution is better than that of oil sealing agent and cerium nitrate solution.After sealing treatment in sodium silicate solution,the zinc phosphating film prepared under ultrasonic condition is composed of Zn_(3)(PO_(4))_(2)·4H_(2)O,Zn_(2)Fe(PO_(4))_(2)-4H_(2)O,ZnSiO_(3) and Na_(2)SiO_(3)phases and shows good compactness and corrosion resistance.The time against corrosion of copper sulfate dropping exceeds 150 s,and the corrosion current density is as low as 3.×10^(-6)A/cm^(2),which is nearly an order of magnitude lower than that of the unsealed zinc phosphating film prepared under ultrasonic condition.Corrosion leveling phenomenon occurs during the sealing process of zinc phosphating film in sodium silicate solution,and ZnSiO_(3)is formed and Na_(2)SiO_(3)is precipitated which can play the role of filling the pores.Therefore,the compactness of the zinc phosphating film prepared under ultrasonic condition is improved to a greater extent,thus significantly enhancing the corrosion resistance.

关 键 词：锌系磷化膜 超声波 封闭处理 耐蚀性 硝酸铈溶液 硅酸钠溶液 

分 类 号：TQ153[化学工程—电化学工业]