Microstructural Evaluation of Tungsten Carbide-Cobalt (WC-17Co) Alloy Deposited by Cold Spraying, High Velocity Air Fuel, and High Velocity Oxygen Fuel Spraying Technologies

Various thermal spraying methods can be used to deposit Tungsten carbide cobalt (WC-Co), however changes in the type of spraying technology could have significant effects on the resulting properties. High Velocity Oxygen Fuel (HVOF) technology is a well-known technique for deposition of WC-Co for commercial applications. Another advanced deposition system that exclude additional use of oxygen known as High Velocity Air Fuel (HVAF) has commercially been available for deposition coating with high quality. It is speculated that application of deposition methods such as HVAF will result in reduction of decarburization in WC-Co coatings compared to HVOF deposited WC-Co. Recently, a specific cold spraying technology commercially known as Kinetic Metallization (KM) has been introduced to the industry that is capable of deposition of high-quality WC-Co coatings. This study evaluates important microstructural features and characteristics of WC-17 Co coatings deposited by HVOF, HVAF, and KM processes. Elemental and phase composition using EDS and XRD, microstructural observation by Optical Microscopy, SEM, and TEM, porosity measurement using image analysis, and density measurements of three different coatings will be compared here. Results obtained from this study can be used for future investigation in thermo-mechanical properties of WC-Co coatings.