WEAR AND CORROSION BEHAVIOUR OF HVOF COATINGS ENGINEERED FROM CONVENTIONAL WC-CO-CR AND CONVENTIONAL WC-CO-CR ADDED NANOSTRUCTURED WC-CO POWDERS

Tungsten carbide base coatings deposited by High Velocity Oxy-Fuel (HVOF) technique are the most common materials deposited in order to protect the components surface against wear and corrosion. The purpose of this study is to investigate the sliding and abrasion wear and also the corrosion behaviour of HVOF coatings engineered from conventional WC-10Co-4Cr and conventional WC-10Co-4Cr with addition of WC-15Co nanostructured powders. A 5% addition of nanostructured WC-15Co powder was added to a conventional WC-10Co4Cr powder in order to improve the properties of the coating. The coatings have been characterized by SEM equipped with EDAX analyzer, XRD as well as the microhardness testing were performed. The wear behavior was evaluated by means of rubber wheel abrasion and ball-on-disk tests. The worn surfaces have been investigated by FESEM microscope and optical profilometer. The corrosion behavior of the coatings were tested with electrochemical open-cell potential measurements. The results showed that the nanostructured powder had a positive influence on sliding wear and corrosion behavior of the coating in comparison with the conventional coating.