Tribocorrosion behaviour of cemented carbide coatings obtained by high velocity oxygen fuel spraying

Erosion-corrosion experiments on carbide coatings were conducted to quantify the contributions of erosion and corrosion components to the total wear weight loss. WC-17Co, WC-12Co and Cr3C2-25NiCr coatings were deposited by HP-HVOF spray onto steel substrate. Wear-corrosion tests were carried out in a rotatory tribometer. The main degradation mechanisms were evaluated by electrochemical methods and SEM. Erosion-corrosion tests showed that all of the sprayed coatings were strongly affected by the action of the erosive agent in the liquid media combining wear and corrosion. The main degradation forms were dissolution of the binder matrix at the hard phase/matrix interface followed with pulling out of the carbides. Cr3C2coatings were found to possess the lowest wear resistance among all the tested coatings.