Ramadev Herle

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 3 M 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.

Propanoyl(1Z)-N-(2,6-dimethylphenyl)-2-oxopropanehydrazonoate as inhibitor for corrosion of 6061 Al alloy15 % (v) SiC(p) composite in hydrochloric acid media

The corrosion inhibition effect of Propanoyl(1Z)- N-(2,6-dimethylphenyl)-2-oxopropanehydrazonoate (PDOH) on the corrosion of 6061 Al alloy-15%(v) SiC(p) composite in 0.5 and 1M hydrochloric acid medium at four different temperatures (30, 40, 50 and 60 ⁰C) have been investigated using potentiostatic polarization (Tafel extrapolation and Linear polarization) and Weight loss methods. The results obtained revealed that PDOH is an efficient inhibitor with 96 % of inhibition efficiency in the range of temperatures studied. Leftward and downward shifts in Tafel plots are observed on the addition of the inhibitor, indicating that PDOH inhibits the corrosion process and it is a cathodic inhibitor. Corrosion rate increases and inhibitor efficiency decreases with increase in temperature. Results obtained by Tafel extrapolation, Linear polarization and weight loss methods are in good agreement. The adsorption of the inhibitor on the 6061 Al alloy 15 % (v) SiCp composite surface was found to obey Temkin’s adsorption isotherm that verifies the assumption of mono-layer adsorption on a uniform homogeneous composite surface with an interaction in the adsorption layer. The inhibition is governed by physisorption mechanism