Improved corrosion resistance of air plasma sprayed WC-12%Co cermet coating by laser re-melting process

By Deen, K. M.; Afzal, M.; Liu, Y.; Farooq, A.; Ahmad, A.; Asselin, E.
Published in Materials Letters NULL 2017

Abstract

Abstract WC-12%Co cermet coating was deposited on {AISI} 321 stainless steel by air plasma spraying. The coated samples were re-melted by {CO2} laser beam at 100 mm/min travel speed. The microstructural features after laser re-melting treatment demonstrated an appreciable decrease in the concentration of micro-defects. The significant improvement in the corrosion resistance and barrier properties of the laser re-melted coating was also evident from potentiodynamic polarization and impedance spectroscopy analyses. The laser re-melted coated samples had a lower corrosion current density (2.1 ?A/cm2) and higher charge transfer resistance (1.4 k?-cm2) in combination with high coating resistance (40.30 k?-cm2).

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