The combination of carbon nanotube buckypaper and insulating adhesive for lightning strike protection of the carbon fiber/epoxy laminates

Carbon fiber reinforced polymers (CFRP) have been increasingly used in aircraft structures. However, their relatively low electrical conductivity leads to the vulnerability to lightning strike. Herein, the carbon nanotube buckypaper-based coatings composed of conductive buckypaper and insulating adhesives were developed to protect the CFRP laminates. Their influence on the lightning strike protection (LSP) effectiveness was systematically studied and the possible mechanisms were discussed. It was demonstrated that the conductive layer of buckypaper could facilitate the lightning current to the ground and dissipate the energy. Moreover, a relatively thick insulating adhesive could hinder the transfer of the lightning current through the thickness direction to CFRP laminates, thus further enhance the LSP effectiveness. An optimized LSP coating developed in this work was composed of a ∼70 μm thick buckypaper and a ∼200 μm thick boron nitride modified epoxy insulating adhesive, which resulted in a weight reduction up to 30% compared to the commercial Cu LSP coating, and could sustain the simulated lightning strike with peak current up to 100 kA.