Development of Cold-sprayed Boron Carbide Metal Matrix Composite Coatings for Wear Resistance Applications

Abstract

Low-pressure cold spraying was used to fabricate boron carbide-based metal matrix composite coatings for wear resistance applications. Titanium carbide and tungsten carbide-based metal matrix composite coatings were also evaluated to allow for comparison. Powder blends containing 50, 75, and 92 wt.% carbide particles with the remaining mass composed of nickel powder were deposited, then characterized and tested. The velocity and momentum of the different impacting ceramic particles were estimated using a mathematical model. Scanning electron microscopy, image analysis, and X-ray diffraction (XRD) were used to characterize the microstructure of the coatings. The image analysis was used to determine the reinforcing carbide particle loading and the mean free path between reinforcing particles. It was found that the velocity and momentum of the carbide particles was not the dominant factor in their deposition efficiency; in fact, it was the carbide particles with highest momentum and highest fracture toughness that had the highest deposition efficiencies. Vickers micro-hardness, dry abrasion tests, adhesion tests, and preliminary corrosion tests were conducted to evaluate the performance of the coatings. Overall, the micro-hardness and wear resistance increases with increasing reinforcing particle content. Additionally, it was found that the carbide particles with high momentum produced a work hardening effect on the matrix, which led to improvements in the coating properties. In cold spray deposition of metal matrix composite coatings, high fracture toughness in the ceramic powder and high impact momentum of the ceramic particles can improve the micro-hardness and wear resistance of the deposited material.