Investigating the effect of lubrication on the wear behavior of WC-12Co coating applied by HVOF method on steel substrate

Cemented carbides of the WC-Co family are one of the most popular materials for use in industry. Despite its high hardness, WC-Co has the appropriate toughness for applications where wear resistance is required. In this study, WC-12Co coating was deposited on a 304 steel substrate using the HVOF thermal spraying method. Microstructural examination of the cross-section of the applied coating and the coating surface was performed using a scanning electron microscope (SEM). Then, X-ray diffraction (XRD) analysis was performed on the deposited coating surface. Mechanical property tests including: hardness testing, surface roughness, fracture toughness, and porosity of the obtained coating surface were also performed. Also, the coatings deposited on the steel surface were subjected to pin wear tests on the disk with loads of 20 and 40 N, in dry and wet environmental conditions (using deionized water as a lubricant) and using a 52100 steel scraper pin.The scratched surfaces were imaged using SEM. The test results showed that the applied coating reduced the friction coefficient, reduced weight, and had a lower scratch penetration depth than the uncoated sample. It was further determined by adding lubricant to the contact surface between the coating and the scratcher that the uncoated and coated samples experienced a lower friction coefficient and weight loss compared to their dry state. Also, the scratch penetration depth in the sample in wet conditions was lower than in its dry state