Corrosion polarization behaviour and inhibition of S40977 stainless steel in benzosulfonazole/3?M H 2SO 4 solution

摘要

Benzosulfonazole was evaluated for its corrosion inhibition effect on S40977 stainless steel in 3?M H 2 SO 4 solution through potentiodynamic polarization, open circuit potential measurement, optical microscopy and IR spectroscopy. Results obtained showed the effective performance of the compound with values of 77.33%–88.32% inhibition efficiency, at 0.25%–1.25% inhibitor concentration from electrochemical analysis. Corrosion potential value decreased from ?0.359?V to ?0.306?V upon addition of the compound at 0.25% concentration, which decreased progressively to ?0.278?at 1.25% concentration. 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 to be through chemisorption mechanism according to Langmuir, Freundlich and Temkin adsorption isotherms. Micro-analytical images showed a severely corroded morphology with corrosion pits in the absence of benzosulfonazole which contrast the images obtained with the inhibitor addition. The compound was determined to be mixed type inhibition. Highlights ? Benzosulfonazole effectively inhibited the corrosion of S40977 stainless steel in 3?M H 2 SO 4 . ? The compound adsorbed onto the steel according to Langmuir, Freundlich and Temkin isotherm. ? The functional groups responsible for inhibition were identified through IR spectroscopy. ? Corrosion potential from ?0.359?V to ?0.278?V upon addition of the compound. ? Micro-analytical images of the inhibited steel significantly contrast the unprotected steel.