无铬达克罗钝化剂的选择

Selection of Passivation Agents for Preparation of Cr-Free Dacromet Coating

为了提高无铬达克罗技术的耐蚀性,使无铬达克罗在成膜过程中形成致密钝化膜,在无铬达克罗涂液中添加不同钝化剂,采用胶带试验、弯曲试验、划痕试验、盐雾试验、硝酸铵快速检测法等评价了涂层性能,采用电化学工作站测量涂层的极化曲线、开路电位等,考察了锌铝涂层的性能和对铁基体的电化学保护情况。结果表明,添加钼酸盐后的钝化效果最好。

Various passivation agents were introduced into fluids for preparing Cr-free Dacromet coating,aiming at forming compact passivation film and increasing corrosion resistance of the coating.The performance of the resulting coating was tested making use of tape test,bending test,salt-spray test,and accelerated ammonium nitrate anti-corrosion performance test.The polarization curve and open circuit voltage of the coating were tested using an electrochemical work station,and the performance of zinc-aluminum coating and its protection to the iron matrix were investigated.Results indicated that the best passivation effect was obtained after adding molybdate as the passivation agent.