Electrical Conductivity of Metal–Polymer Cold Spray Composite Coatings onto Carbon Fiber-Reinforced Polymer

Abstract : Cold spray is a promising process to coat polymers and carbon fiber-reinforced polymer (CFRP). The choice of the metal-polymer couple of materials, however, has a strong influence on coating build-up and properties. In the present work, we show that spraying mixtures of copper and polymer particles lead to composite coating. We observe that the polymer promotes coating build-up onto CFRP to the expense of the electrical conductivity of the coating as a result of its insulating properties. The present work investigates the influence of the coating microstructure on electrical conductivity. Various copper powders, with different morphologies, particle sizes and oxygen contents were mixed with a PEEK (Polyaryl-Ether-Ether-Ketone) powder. Cold spray of these powders resulted into composite coatings and we study the microstructures and electrical properties of such coatings as a function of powder characteristics and spraying parameters. A morphological model of the coating microstructure was developed to reproduce numerically microstructures in 3D. The conductivity of the coatings was measured experimentally for various copper powders. Careful selection of blends of copper and PEEK powders coupled with optimized spraying parameters led to metal-polymer coatings onto CFRP with a fairly high electrical conductivity.