Embedment of copper particles into polymers by cold spray

Cold spray was used to embed copper particles into 6 different polymers – polyurethane, high density polyethylene, polypropylene, nylon 6, polytetrafluoroethylene and polycarbonate – without coating buildup. During impact, penetration of the particles and polymer flow around them resulted in their capture by the surface. The effects of spray temperature and traverse speed on particle penetration, sample weight gain and polymer deformation were investigated. Average embedment depths were determined from cross-sections, and over 50 μm was measured in high density polyethylene and polyurethane. Tribological properties (roughness and self-friction coefficients) and electrical sheet resistance of the Cu-embedded surfaces were studied. The embedding technique may find utility in functionalizing polymer surfaces that do not withstand high temperature coating methods, which provide poor adhesion for paint films, or where flexibility of the polymer needs to be maintained.