Corrosion and Corrosion Inhibition Studies on Mg Al Zn alloy In Aqueous Ethylene Glycol 30 V V Medium

Abstract

Magnesium alloys find applications from automobile industries to medical implant newlinematerials because of its enhanced properties in comparison with other light weight alloys. newlineMg-Al-Zn alloy is one such magnesium alloy, which finds variety of applications in newlineautomobile industries. The occurrence of corrosion is beneficial in the medical field of newlineapplication as it avoids one more surgery for the removal of implants, but is a limitation in newlineautomobile industry applications. Therefore, the study of corrosion and its controlling newlinemeasures have vital role in practical applications. newlineIn this thesis, corrosion of Mg-Al-Zn alloy and its mitigation were studied using newlineelectrochemical techniques - potentiodynamic polarization and AC impedance spectroscopy. newlineThe surface morphology and surface composition of the corroded alloy surface were newlineexamined by SEM and EDX analyses. The aqueous ethylene glycol (30% v/v) solutions, newlinecontaining chloride and sulfate ions, were chosen as the corrosive media. The corrosion newlinestudies were performed at different chloride ion and sulfate ion concentrations, pH and newlinetemperature of the medium. The obtained results concluded the trend of higher corrosion rate newlineat higher concentration of chloride and sulfate ions, lower pH and higher temperature. newlineThe synergistic mixtures of sodium dodecyl benzene sulphonate (SDBS) with newlinetrisodium phosphate (TSP) and sodium benzoate (SB) were employed as corrosion inhibitors. newlineSimilarly morpholine and its two derivatives N-methyl morpholine and dimethyl morpholine newlinewere also studied as corrosion inhibitors in the corrosive media. The synergistic mixtures newlineacted as anodic type inhibitors by suppressing anodic reaction. The morpholine and its newlinederivaties acted as mixed type inhibitors. All the inhibitors were more effective at lower newlinetemperature and in higher concentration of the corrosive media. The activation and newlinethermodynamic parameters have been calculated and documented.