Comparative study of corrosion performance of HVOF-sprayed coatings produced using conventional and suspension WC-Co feedstock.
Faisal, Nadimul Haque
Al-Anazi, Nayef M.
Goosen, Mattheus F. A.
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AHMED.R., VOURLIAS, G., ALGOBURI, A., VOGIATZIS, C., CHALIAMPALIAS, D., SKOLIANOS, S., BERGER, L.-M., PAUL, S., FAISAL, N.H., TOMA, F.-L., AL-ANAZI, N.M and GOOSEN, M.F.A. 2018. Comparative study of corrosion performance of HVOF-sprayed coatings produced using conventional and suspension WC-Co feedstock. Journal of thermal spray technology [online], 27(8), pages 1579-1593. Available from: https://doi.org/10.1007/s11666-018-0775-2
Corrosion properties of nanostructured coatings deposited by suspension high-velocity oxy-fuel (S-HVOF) via an aqueous suspension of milled WC-Co powder were compared with conventional HVOF-sprayed coatings. Microstructural evaluations of these coatings included x-ray diffraction and scanning electron microscopy equipped with an energy-dispersive x-ray spectroscopy. The corrosion performance of AISI440C stainless steel substrate and the coatings was evaluated in a 3.5 wt.% NaCl aqueous solution at ~25 °C. The electrochemical properties of the samples were assessed experimentally, employing potentiodynamic polarization and electrochemical impedance spectroscopy. The potentiodynamic polarization results indicated that coatings produced by S-HVOF technique show lower corrosion resistance compared with the coatings produced by HVOF-JK (HVOF Jet Kote) and HVOF-JP (HVOF JP5000) techniques. Results are discussed in terms of corrosion mechanism, Bode and Nyquist plots, as well as equivalent circuit models of the coating–substrate system.