Effects of dodecyltrimethylammonium bromide surfactant on both corrosion and passivation behaviors of zinc electrodes in alkaline solution

Abstract

The corrosion and passivation behaviors of zinc electrodes in 7.0 M KOH saturated with ZnO in the presence of dodecyltrimethylammonium bromide (DTAB) surfactant were evaluated by Tafel, linear sweep voltammetry, electrochemical impedance spectroscopy (EIS) and field emission scanning electron microscopy (FE-SEM) tests. It was found that DTAB had a considerable effect on inhibiting zinc corrosion by the adsorption of DTAB. The adsorption of DTAB obeyed the Freundlich isotherm. Tafel polarization curves revealed that DTAB worked as an anodic-type inhibitor. The highest corrosion inhibition efficiency of DTAB was up to 80.2% in the presence of 0.07 wt% DTAB. In addition, potentials of both passivation and anodic dissolution current peak positively shifted in the presence of DTAB, indicating that the passivation was delayed. Based on the EIS tests and FE-SEM analysis in the presence and absence of DTAB, it was shown that the adsorption and favorable moisture retention of DTAB were beneficial to the formation of uniform and fluffy protective layer on the surface of zinc electrode. Such a morphological modification of zinc surface greatly improved the diffusion rate of ions and the utilization of zinc electrode.