汽车涂装锆盐前处理的关键工艺参数优化

Optimization of key process parameters for zirconization prior to automotive painting

研究了汽车涂装前处理锆化槽液中不同Zr^(2+)质量浓度、pH、浸渍时间和温度对冷轧板和镀锌板电泳后耐腐蚀性能的影响。通过中性盐雾试验衡量板材的防腐性能,利用SEM表征锆化膜的表面形态。结果表明:当槽液温度为20℃,Zr^(2+)质量浓度为1.1 g/L,pH=4.5,处理时间为90 s时,所得的锆化膜结构致密,无裂纹,均匀性好,耐酸/碱性1级,电泳后盐雾试验至960 h时的平均腐蚀宽度符合车身用板材的要求。

The effects of Zr^(2+)mass concentration,pH,immersion time,and temperature on the corrosion resistance of cold-rolled steel sheet and hot-dip zinc-coated steel sheet after electrophoretic painting were studied.The corrosion resistance of the steel sheets was measured by neutral salt spray(NSS)test,and the surface morphology of the zirconization film was characterized by scanning electron microscopy(SEM).The results showed that the zirconization film prepared with 1.1 g/L of Zr^(2+)at temperature 20℃and pH 4.5 for 90 s had a compact,uniform,and crack-free structure,and had a 1-grade acid/alkaline resistance.The average corrosion width of the electrophoretically painted zirconization film after 960-hour NSS test met the requirement of the car body panels.