Corrosion study of brazing Cu Ag alloy in the presence of benzotriazole inhibitor

The effect of benzotriazole (BTA) on the corrosion behavior of brazing CuAg alloy in deionized water was investigated using corrosion potential measurements, potentiodynamic polarization and X-ray photoelectron spectroscopy (XPS). Pure Cu, pure Ag and a high Cu alloy were included for comparison. The electrochemical responses show that BTA shifts the corrosion potential of Cu to the noble direction but has the opposite effect for Ag and a mixed behavior for the CuAg alloys. The inhibition efficiency of BTA for Cu and high Cu alloy reached around 95% but was significantly lower for Ag and the brazing CuAg alloy. XPS results show the formation of Cu- and Ag-BTA complexes through the N tail of BTA. The lower inhibition efficiency of Ag and brazing alloy can be attributed to the weak adsorption of BTA on the Ag phase leading to lower corrosion protection of Ag.