Polymer metallization via cold spray additive manufacturing: A review of process control, coating qualities, and prospective applications

Polymer metallization via cold spray additive manufacturing is an emerging thermal spray approach for deposition of thick metallic coatings on polymers and fiber-reinforced composites that promises high productivity, ecofriendliness, and scalability of the coating process. In polymer metallization via cold spray, solid metallic powder is accelerated by a supersonic stream of preheated gas and propelled toward a polymer substrate, where it is built layer-by-layer via impact-induced heating and particle deformation. Since the pioneering study at Cambridge in 2006, nearly 50 experimental reports on polymer metallization via cold spray have been published, half of which have appeared within the past three years. This review distinguishes cold spray from other thermal spray methods, analyzes the peculiarities of cold spraying on polymers and fiber-reinforced composites, outlines the historical establishment of the field, and summarizes the available literature on polymer metallization via cold spray. The major focus here is on the influence of the cold spray process parameters on the deposition efficiency, adhesion strength, electrical conductivity and other properties of metallic coatings formed on polymers and fiber-reinforced composites. The promising applications of cold spray additive manufacturing in lightning strike protection, electroplating, osseointegration, antifouling, antivirus, e.g. anti-Covid-19 surfaces, and other surface functionalizations have been reviewed. Finally, recommendations were given on how to enhance the data reuse in future studies on polymer metallization via cold spray.