EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Recent work indicates that HVOF thermal spraying WC-Co coatings have been used to enhance the wear resistance of various engineering components in a variety of industrial environments. In the present work WC-Co powder containing Cr particles in an amount of 10% was deposited on ductile cast iron with high velocity oxy-fuel (HVOF) thermal spray coating technique. An investigation was conducted to determine the role of Cr particles in the WC-Co coating produced with HVOF technique on microstructure, mechanical and wear properties in a system of type: WC-Co coating/ductile cast iron. The microstructure of the HVOF-sprayed WC-Co+Cr coating was characterized by light microscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS). The analysis of the microstructure showed the formation of coating with low porosity, compact structure, good adhesion to the substrate with typical lamellar structure composed of a fine molten Cr particles and finely fragmented WC grains embedded in a Co matrix, coming to the size of nanocrystalline. For analysis of the adhesion of coatings to the substrate, the scratch test was applied. An assessment of the erosive wear resistance of coatings was also carried out, confirming the significant impact of Cr particles as well as the microstructure and phase composition of the carbide coating on the wear resistance of the tested coating system. Moreover, the results were discussed in relation to the bending strength test, including cracks and delamination in the system of the WC-Co+Cr/ductile cast iron as microhardness and erosion resistance of the coating. It was found that the addition of Cr particles was significantly increase resistance to cracking and wear behaviour in the studied system.