Effect of benzotriazole on electrochemical and corrosion behaviour of type 304 stainless steel in 2M sulphuric acid solution

Abstract

The effect of benzotriazole (C₆H₃N₅) as a corrosion inhibitor for type 304 stainless steel in 2M H₂SO₄ has been studied using weight loss experiments, anodic and cathodic potentiostatic measurements, atomic emission spectrometry, and optical and scanning electron microscopy. Benzotriazole acted as a corrosion inhibitor over the entire range of potentials studied, from −625 to + 1250 m V with respect to a saturated calomel electrode, and did not promote selective alloy dissolution. The protective film was stable and adherent and obeyed the Langmuir isotherm, while values of the equilibrium adsorption constant suggested chemical adsorption. The maximum coverage obtained was 0·97 for stirred solutions and 1·0 for unstirred solutions, these values being associated with partial dissolution and lack of dissolution of inclusions respectively.