The corrosion inhibition of certain azoles on steel in chloride media: Electrochemistry and surface analysis

• Several azoles were tested as corrosion inhibitors for C15 mild steel.
• Tolyltriazole was the most effective corrosion inhibitor.
• C15 steel corrosion in inhibited solution is kinetically-controlled.
• Inorganic salts did not show significant synergistic effect.

This study analyses the corrosion inhibition efficiency of certain azoles for C15 grade mild steel in 3 wt.% NaCl solution by employing immersion tests and different electrochemical techniques. The possible synergistic effect of azole inhibitors and metal salts was also investigated. It was found that tolyltriazole is the most effective corrosion inhibitor. Additional surface analyses were performed for specimens inhibited with tolyltriazole. ATR-FTIR analysis confirmed the adsorption of tolyltriazole on the steel surface and 3D‐profilometry and AFM showed that tolyltriazole reduces surface roughness compared with non‐inhibited solution. Contact angle analysis showed that tolyltriazole-inhibited steel specimens evidenced a hydrophilic character.