Effect of benzotriazole on the prevention of electroless nickel–immersion gold treated copper corrosion

The effect of benzotriazole on the corrosion prevention of electroless nickel–immersion gold (ENIG)-treated copper in 3.5 wt% sodium chloride solution was investigated using electrochemical tests, qualitative and quantitative surface analyses, and density functional theory calculations. Benzotriazole showed high corrosion inhibiting efficiency of approximately 90% or more for both copper and nickel, which are components of ENIG-treated copper. Furthermore, adding benzotriazole suppressed more than half of galvanic corrosion between nickel and gold, previously identified as the cause of corrosion of ENIG-treated copper. By chemisorption of its nitrogen atoms on the copper and nickel surfaces, benzotriazole effectively inhibited corrosion of ENIG-treated copper. The corrosion and corrosion inhibition mechanisms of ENIG-treated copper specimens were investigated using scanning electron microscopy with energy-dispersive X-ray spectroscopy after immersion testing of ENIG-treated copper specimens.