Study of corrosion inhibition of mild steel in acidic medium by 2-propargyl- 5-p-chlorophenyltetrazole : Part I

2-propargyl-5-p chlorophenyltetrazole (PCPT) was tested as corrosion inhibitor for mild steel in 1M HCl solution using electrochemical and weight loss measurements. Results obtained showed that this compound has a good inhibiting properties for mild steel corrosion in acidic medium, with inhibition efficiencies values reach 98% at 5*10-4 M . The inhibition was assumed to occur via adsorption of the PCPT molecules on metallic surface. Adsorption of inhibitor molecules on steel surface showed Langmuir adsorption isotherms fit in acidic media. Potentiodynamic polarization curves showed that the inhibition is a cathodic nature. In addition, results obtained by weight loss and electrochemical measurements are in good agreement. Mechanism of physical adsorption is proposed from the apparent activation energy (Ea) and the thermodynamic parameters obtained. The adsorption of the PCPT on the mild steel surface is spontaneous.