Synergistic Effect of Benzonitrile and Benzothiazole on the Corrosion Inhibition of 316 Stainless Steel in 6M HCl Solution

The synergistic effect of the combined admixture of benzonitrile and benzothiazole (BBZ) on the corrosion inhibition of 316 austenitic stainless steel in 6M HCl solution was evaluated through potentiodynamic polarization, coupon measurement, optical microscopy and IR spectroscopy analysis. Results obtained showed the effective corrosion inhibition performance of the admixture with optimal inhibition efficiency value of 95%. Identified functional groups of alcohols,phenols, amines, amides, carboxylic acids, aliphatic amines, esters and ethers within the compound completely adsorbed onto the steel from analysis of the adsorption spectra while others decreased in intensity due to partial adsorption.Thermodynamic calculations showed the cationic adsorption through chemisorption mechanism according to Langmuir and Freundlich adsorption isotherms. Micro-analytical images showed a badly corroded morphology with corrosion pits in the absence of compounds which contrast the images obtained with the compound. The compound was determined to be mixed type inhibition