Cold spraying of metallic powders onto polymeric substrates : window of deposition and bonding mechanisms

Common issues such as ice accretion formed on wind turbine blades and lightning strikes aeroplane can be mitigated by metallizing polymers and composites that are used in the outer surface. Cold gas dynamic spray is a novel application that has potential to metallize the surface of polymer and composites to produce electrically and/or thermally conductive components. In this study, mixed copper-zinc and aluminium-zinc feedstock powders were deposited onto polypropylene and nylon-6 substrates to investigate the viability of metallizing non-metallic surfaces using low-pressure cold spray process. The behaviour of the individual metallic particles upon impact on the polymers and the deformation of the substrate was characterized by performing swipe tests and observed using scanning electron microscopy. Both feedstock powders were coated onto nylon-6 substrate using a wide range of temperature, pressure, scanning speed and stand-off distance to develop a process parameter window. Coating thickness up to 1 mm was deposited for the Cu-Zn coating onto nylon-6 substrate using optimised parameters. Electrical conductivity has been measured using 4-point probe technique and 51 % IACS was measured for Cu-Zn coating onto nylon-6 sprayed at 0.6 MPa and 481 °C.