Corrosion inhibition of zinc in tetra-n-butylammonium bromide aerated aqueous solution by benzotriazole and Na3PO4

The effect of benzotriazole (BTA), Na3PO4 and their mixture on the corrosion of zinc in 17 wt.% (0.534 mol l−1) tetra-n-butylammonium bromide (TBAB) aerated aqueous solution has been investigated by means of weight-loss test, potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS) and SEM/EDX techniques. The experimental results showed that BTA or Na3PO4 or inhibitor mixture could protect zinc in aqueous TBAB solution. The inhibitor combinations led to higher efficiencies compared to those obtained when added individually. An inhibition efficiency of an inhibitor mixture consisting of 0.5 g l−1 BTA and 1 g l−1 Na3PO4 was more than 97%.

Research highlights
► BTA or Na3PO4 or inhibitor mixture could protect zinc in aqueous TBAB solution.
► The BTA/Na3PO4 mixture showed a synergistic effect in the corrosion inhibition.
► The inhibition efficiency was found to increase with increasing BTA concentration.
► The lowest corrosion rate by weight-loss test was 0.71 mg m−2 h−1.