Effect of temperature on the inhibition of corrosion of carbon steels by semicarbazides and thiosemicarbazides

The inhibition of corrosion of 0.12-carbon steel in 1 M HCl by a series of semicarbazides and thiosemicarbazides was investigated by weight loss experiments at temperatures between 303 and 343K. The inhibitors examined were semicarbazide, 4-phenyl semicarbazide, 4,4-diphenyl semicarbazide, thiosemicarbazide, 4-methyl-3-thiosemicarbazide, 4,4-dimethyl-3-thiosemicarbazide, 4-ethyl-3-thiosemicarbazide, and 4-allyl-3-thiosemicarbazide. The inhibitor concentrations were between 1x10(-6) and 1x10(-2) M. Thermodynamic parameters for the adsorption of the inhibitors on the metal surface were calculated using the Temkin adsorption isotherm.