Synergistic inhibitor effect of cetylpyridinium chloride and other halides on the corrosion of mild steel in 0.5Â M H2SO4

► CPC inhibits the corrosion of mild steel in H2SO4 solution. ► Addition of halides to CPC markedly enhances the inhibition action of CPC. ► Chemisorption of CPC was proposed from Picor trend and ΔG0ads values.