Construction of Al-BTA passivation film on the surface of electrolytic copper foil and study of corrosion resistance mechanism

The use of chromates in copper foil metal passivation is becoming increasingly limited due to the emphasis on green production concepts. Thus, it is important to develop a chromium-free passivate that is both environmentally friendly and sustainable. Al(OH)3 passivation films were constructed on the surface of electrolytic copper foils by a simple impregnation method using NaAlO2 as the passivator, and it was found that the addition of a small amount of 1,2,3-benzene propyl triazole (BTA) could significantly improve the corrosion resistance of the passivation film. The passivation mechanism of the composite passivation film was investigated by electrochemical and related characterization tests. The results indicated that the self-corrosion current density (icorr) of the Al-BTA composite passivation film was reduced by two orders of magnitude to 4.375 × 10−7 A/cm2 compared to bare copper, which was better than that of the single aluminum-based passivation film at 5.562 × 10−6 A/cm2. In addition, the smooth and dense surface of the Al-BTA composite passivation film effectively blocked the erosion of corrosive media and protected the copper foil substrate, which has certain prospects for industrial applications.