TITLE:
Electrochemical Characterization of Plasma Sprayed Alumina Coatings
AUTHORS:
Magdi. F. MORKS, Ivan COLE, Penny Corrigan, Akira KOBAYASHI
KEYWORDS:
Plasma Spraying, Alumina Coating, Mild Steel, Corrosion, Polarization, EIS
JOURNAL NAME:
Journal of Surface Engineered Materials and Advanced Technology,
Vol.1 No.3,
October
18,
2011
ABSTRACT: Open circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) were employed to characterize the corrosion behavior of plasma-sprayed alumina-coated mild steel in 3.5 wt% NaCl solu-tion. Alumina-coated steel showed higher OCP and lower corrosion current (icorr.) compared with the steel substrate. However, localized corrosion probably occurs at the coat/steel interface when immersed in the corrosive media. The reason for that is the penetration of corrosive solution into the steel surface through the pores of accumulated alumina layers. The corrosion products (mainly iron oxides) accumulate inside the pores and on the coating surface. The presence of iron oxide slightly improved the corrosion resistance.