Electrochemical studies on the inhibition behavior of composite Udimet 700 – Alumina in 1 M hydrochloric acid by some new organic derivatives
By Abdallah, Y. M.; Elzanaty, Hesham
Published in Materials Chemistry and Physics
2019
Abstract
Corrosion behavior of composite Udimet 700 with (5%& 10%) alumina powder superalloys was studied in 1 M HCl using some new organic compounds “4-((4-aminophenyl) diazenyl) benzene-1,2-disulfonic acid (compound I), N-(benzo[d] thiazol-2-yl) -2-cyanoacetamide (compound II) and ethyl (E)-2-cyano-2- (2-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)hydrazono) acetate (compound III)”. Electrochemical studies were carried out, utilizing potentiodynamic polarization, electrochemical impedance spectroscopic and electrochemical frequency modulation methods. Tafel plots demonstrate that the presence of organic compounds lightly affects the general shape of the polarization bends at 25 °C and acts as a mixed-type inhibitor. The adsorption isotherm model of these compounds on Udimet 700 surface followed Langmuir adsorption isotherm in 1 M HCl solution. The Nyquist plots yield good semicircles, whose radius of curvature increases with expanding the concentration of the tried inhibitors. EFM demonstrated that, the non– straight reaction includes sufficient data about the corroding cycle so that, the current of corrosion can be computed straightforwardly. SEM studies reveal that, the surface morphology shows a marked change in the surface properties after using the organic derivatives. Theoretically by quantum chemical calculations using DFT method fit with theoretical methods.