Corrosion inhibition of mild steel by hexyltriphenylphosphoniumbromide in acid medium. Part-III

The efficiency of hexyltriphenylphosphoniumbromide (HTPPB) as corrosion inhibitor for mild steel in H2SO4 (10(-3) M, 10(-5) M, 10(-7 )M) was investigated by electrochemical methods like steady state galvanostatic and potentiostatic polarization measurements. The dissolution parameters such as corrosion current, passive current, flade potential, cathodic and anodic Tafel slopes and efficiencies were determined and studied at four different temperatures (298 K, 308 K, 318 K, 328 K). The optimum concentration of this compound for maximum inhibition efficiency was determined by galvanostatic method. HTPPB gave more than 92% inhibition in presence of 10(-3) M H2SO4 at 298 K. Potentio dynamic polarization studies revealed that HTPPB is mixed inhibitor and good passivator in 1 M H2SO4. According to temperature kinetics HTPPB obeyed Temkin's and Freundlich adsorption isotherm.