Metallic coating of aerospace carbon/epoxy composites by the pulsed gas dynamic spraying process

A method for applying metallic coatings to high fibre volume fraction aerospace carbon/epoxy polymer matrix composites is presented. The pulsed gas dynamic spraying process was used for depositing zinc coatings on composites featuring a thin layer of copper particles co-cured into the laminate. No surface preparation was required on the cured substrates prior to spraying hence no damage was induced in brittle carbon fibres. Polymer matrix composite substrates with an added layer of co-cured copper particles were manufactured using a standard autoclave process. External substrate heating was not required. Metal powder and epoxy degradation were avoided through low process temperatures. Satisfactory cohesive and adhesive characteristics, low porosities and good microhardness values were obtained for a range of coating parameters. Microhardness and porosity of coatings deposited on polymer matrix composites compared well with those of similar coatings deposited on metallic substrates.