Copper-graphene coatings for improving thermal shielding of CFRPs through electrodeposition techniques

Abstract

Today, carbon fiber reinforced plastics (CFRPs) are materials of interest several industrial sectors because of their mechanical properties and low weight. However, applications in high-temperature areas are limited because of thermal degradation. Thus, thin coatings acting as thermal shielding and ensuring the upkeep of CFRP structural stiffness are of high interest. This work presents an innovative approach to produce copper/graphene bilayer coatings through electrodeposition and electrophoretic deposition; it consists of laser pre-treatment of the composite surface to remove the matrix layer exposing the carbon fibers, enabling the subsequent deposition. Bi-layer graphene/copper coatings exhibit an enhancement in copper electrodeposition efficiency of more than 59% resulting in a 97% stiffness improvement compared to the single layer copper electroplating. All the obtained coatings were able to act as a thermal shield of the CFRPs, reducing the maximum temperature of the composite by more than 60%. In particular, due to the synergistic effect of copper and graphene, the GNPs-Cu coating achieved the highest maximum temperature reduction (81%). Cross-sectional analysis indicates severe delamination in uncoated CFRPs, whereas double-layer coatings maintain structural integrity and prevent delamination even under high-energy exposure. In addition, the coated composites exhibit a higher electrical conductivity compared to the laser cleaned CFRP, with the GNPs-Cu coating that obtained a 90% enhancement because of the outstanding electrical properties of copper and graphene.