THE EFFECT OF TEMPERATURE ON THE ACIDIC DISSOLUTION OF STEEL IN THE PRESENCE OF INHIBITORS

The corrosion of mild steel in sulfuric acid containing 4 × 10-4 M of either D-galactose thiosemicarbazone, 1-phenyl thiosemicarbazide, or 4-phenyl thiosemicarbazide has been studied over the temperature range 25 to 60°C by using alternating current (AC) impedance spectroscopy and measuring the capacitance of the double layer. Results elucidate the effect of temperature and molecular structure on inhibition efficiency. The anodic dissolution process was under activation control for all the compounds investigated at different temperatures. The inhibitors investigated do not affect the mechanism of the dissolution process. Thermodynamic parameters for adsorption of the compounds are calculated using the Temkin adsorption isotherm.