Depositing Metallic Coatings on Polymer Substrates by Cold Spray Process

Metallization of the polymers is an attractive way of improving their electrical and erosion properties. However, it is still challenging to achieve a dense metal coating on polymer surfaces by thermal spray processes, due to excessive surface erosion during the processing. Cold spray (CS) is a successful and promising coating technique for many engineering applications due to its high-rate and high-dense coating development abilities. Nevertheless, their practical use in polymer substrates is still in the fledgling phase. This paper presents the results on the potential of the CS process to produce metallic coatings on non-metallic surfaces such as polymers and composites. In order to rationalize the behavior of the high velocity particle with the substrates, three thermoplastic polymers were selected as a substrate, i.e., PEEK, ALTEM, and ABS. The result showed that the particle behaviors were unique with respect to the substrate. Also, it was clearly understood that the metal particles not experienced any plastic deformation due to the soft nature of the polymer substrates. The properties of the coatings, such as adhesion strength, Vickers hardness and electrical resistivity, were measured and the influence of the coating thickness on the above properties and bonding behavior was also evaluated.