| A low-cost, low-pressure cold spray unit was used to fabricate tungsten carbide (WC)-based metal matrix composite (MMC) coatings. A variety of coatings were fabricated and characterized. Scanning electron microscopy (SEM), coupled with image analysis, Vickers micro-hardness, and X-ray diffraction (XRD) were used to characterize the coatings. Image analysis was used to determine the WC content in the coatings and the mean free path between the reinforcing particles. The WC content in the coating increased as the WC content in the powder blend increased. As the WC content in the powder increased, the coating porosity decreased and the WC deposition efficiency increased. ASTM standard G65-2004 dry abrasion testing was conducted on WC-Ni coatings to determine a relationship between hardness and wear resistance. A linear relationship was observed between the wear rate and hardness of the WC-Ni MMC coatings. The coating deemed optimal had a wear rate comparable to those of WC-Co coatings fabricated by high-velocity oxy-fuel (HVOF) and high-pressure cold spraying. |
