针对铸造铝合金的成分和性能特点，设计了四元浸锌工艺，用于铸造铝合金的镀前处理。采用加热试验法检测镀层的附着力；使用扫描电镜和X射线衍射仪对镀层的表面形貌和相结构进行了分析。结果表明: 随着浸锌时间的延长，四元浸锌层越来越致密，浸锌60~90 s可满足铸造铝合金镀前处理要求；经过四元浸锌处理后的镀铜层具有较好的附着力；XRD分析显示镀铜层为多晶结构；焦磷酸盐镀铜层表面比较粗糙，存在较多孔隙；进行硫酸盐镀铜处理后，表面更为平整，针孔缺陷得到有效抑制。

According to the chemical composition and properties of cast aluminum alloys, four-element immersion zinc process was designed and used as the pretreatment for copper electroplating. Heating method was employed to measure the adhesion property of electroplating coating. SEM and XRD were applied to analyze the coating morphology and phase structure. The results show that with the increase of immersion zinc time, the density of zinc coating increased. The optimal time of immersion zinc was 60~90 s. The pretreatment process of four-element immersion zinc can enhance the adhesion of electroplating coating. The XRD result indicated that the copper electroplating coating was crystal structure. The pyrophosphate copper plating coating had a coarse surface and many pinholes. After sulfate copper plating, the coating surface became smooth, and pinhole defect was controlled efficiently.