Title: Corrosion and passive film study of cermet-coatings deposited by high-velocity oxygen fuel method in an acidic environment
Authors: Akbar Niaz
Addresses: Department of Materials Engineering, Collage of Engineering, King Faisal University, P.O. Box 380, Postal Code 31982, KSA
Abstract: Cermet coatings are used for wear resistance applications, and it is generally understood that deterioration predominantly occurs due to frictional and erosion forces between two parts of mediums. The electrochemical corrosion of the cermet coating is partially studied. The focus of the present work is on the detailed electrochemical corrosion study of WCCoCr coatings. The mild steel samples surfaces were cleaned by sandblasting before depositing multi-layers of coatings carried out by the high-velocity oxygen fuel method. The electrochemical corrosion testing was carried out by recording potential vs. time curves, potentiodynamic polarisation, and impedance spectroscopy. The formation of oxides in the air and as a function of increasing voltage is studied by X-ray photoelectron spectroscopy. Our experimental results revealed that under stagnant conditions, electrochemical properties significantly change with time. The coating deterioration is expected to be worse in dynamic conditions where coatings surfaces are renewed by rubbing, sliding, or erosion conditions.
Keywords: cermet coatings; electrochemical testing; corrosion degradation; impedance spectroscopy; coating passivation; oxides characterisation; WCCoCr coatings.
International Journal of Surface Science and Engineering, 2020 Vol.14 No.3, pp.175 - 191
Received: 23 Oct 2019
Accepted: 21 Dec 2019
Published online: 08 Oct 2020 *