Chemical Engineering Communications, Vol.198, No.1, 120-130, 2010
Inhibiting Effect of N-cyclohexyl-N'-phenyl Thiourea on the Corrosion of 304 SS in Hydrochloric Acid Solution
The inhibiting action of N-cyclohexyl-N'-phenyl thiourea (CPTU) on the corrosion behavior of 304 SS in 3M hydrochloric acid solution has been investigated using potentiodynamic polarization technique at four different temperatures. The results obtained reveal that CPTU acts as an efficient anodic inhibitor for the corrosion of 304 SS. Good inhibition efficiency (92%) was evident in the acidic solution, and it was found to vary with temperature and concentration of the inhibitor. The adsorption of this compound on the 304 SS surface was found to obey the Temkin adsorption isotherm, and the inhibition was governed by physical adsorption mechanism. The thermodynamic parameters of adsorption deduced revealed a strong interaction and spontaneous adsorption of CPTU on the steel surface. Scanning electron microscopic study (SEM) was done to investigate the surface characterization of inhibited and uninhibited 304 SS specimens.