Characterization And Electrochemical Assessment Of Al-Zn-In Alloy With Trivalent Chromium Process Coating

To reduce self-corrosion of Al-Zn-In pigments in an Al-rich primer, trivalent chromium process (TCP) was applied to the pigments before mixing in the epoxy binder. The formation of TCP and its effects on both the Al-ZnIn bulk alloy and pigment particles were investigated in this study. The TCP layer on the Al-Zn-In alloy has a bilayer structure similar to TCP layers formed on other alloys. The corrosion rate of bulk Al-Zn-In alloy is reduced by the TCP treatment. The TCP layer likely blocks the access of Cl- to the Al-Zn-In alloy, which reduces corrosion attack initiation.