A study of tetrazoles derivatives as corrosion inhibitors of copper in nitric acid

Purpose To evaluate the effect of some tetrazole compounds as corrosion inhibitors of copper in HNO3 at various temperatures. Design/methodology/approach 1‐phenyl‐5‐mercapto‐1,2,3,4‐tetrazole (PMT) was selected as the best inhibitor among the tetrazole compounds tested. Gravimetric and electrochemical techniques were conducted. Findings PMT was an excellent inhibitor for copper in acid. Its efficiency attained 97.5 per cent and decreased slightly with temperature. Research limitations/implications The inhibition efficiency increased with the concentration of PMT to reach 97.5 per cent at 10−3 M. Good agreement between the various methods explored was observed. Polarisation measurements also showed that PMT acted as a mixed inhibitor. Practical implications The efficiency of PMT increased with the concentration but decreased with rise of temperature in the 298‐333 K range. As such, PMT could be used in chemical cleaning and pickling processes. Originality/value The originality of this work was the finding of an efficient inhibitor (PMT) having a nearly 100 per cent efficiency.