High temperature corrosion behaviour of HVOF sprayed WC-CrC-Ni coatings
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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Inderscience Publishers
Abstract
The present work aims to study the hot corrosion resistance of high velocity oxy-fuel (HVOF) sprayed WC-CrC-Ni coating developed on three types of boiler tube materials such as SA213-T22, MDN-310 and Superfer 800 H steels. Hot corrosion studies were conducted in a molten salt environment of Na<inf>2</inf>SO<inf>4</inf>-60%V<inf>2</inf>O<inf>5</inf> at 700°C and thermogravimetric analysis was used to establish kinetics of corrosion. Corrosion kinetics of coated steels followed nearly parabolic behaviour and showed a lower corrosion rate in comparison to uncoated alloys. It is concluded that corrosion is restricted to the external surface of the coating and the formation of thick scale composed of oxides of Cr, Ni and their spinel oxides, acts as a diffusion barrier to the transportation of corrosive species into the coating. The carbides of tungsten and chromium uphold the strength of the coating. © © 2016 Inderscience Enterprises Ltd.
Description
Keywords
Boiler corrosion, Boilers, Carbides, Coatings, Corrosion, Corrosion rate, Corrosion resistance, Corrosive effects, Diffusion barriers, Diffusion coatings, Fuels, High temperature corrosion, HVOF thermal spraying, Nickel metallography, Sodium sulfate, Sprayed coatings, Steel corrosion, Thermogravimetric analysis, Vanadium pentoxide, Characterisation, High velocity oxy fuel, HVOF, Parabolic, Sem/edax, Superfer, Thermo-gravimetric, Corrosion resistant coatings
Citation
International Journal of Surface Science and Engineering, 2016, 10, 4, pp. 400-413