Aerospace Applications of Carbon Nanotubes-based Composites

Israel Aerospace Industries (IAI) is currently engaged in research activities for the development of carbon nanotubes (CNT) based composites for aircraft applications with the goal of providing lightning strike protection (LSP), shielding against electromagnetic interference (EMI), and high intensity radiated fields (HIRF). Mechanical properties are also being investigated as part of the effort to achieve weight reduction over existing solutions. Cooperation with companies in the field of nanotechnology was established, candidate materials were obtained, and proof-of-concept testing was carried out. Collaborations with other companies regarding nanotechnology include the following: Tortech (supplier of multi-walled CNT mats), Airbus (for consultation in the preparation and testing of LSP samples), Nanocore (supplier of materials that promote adhesion of CNT mats to composite surfaces), 2D-Tech (a subsidiary of Versarien and supplier of graphene used for testing effect of graphene on epoxy based composites), N12 technologies (producer of vertically aligned CNTs for improvement of laminate damage resistance and out of plane mechanical properties), and General Nano (supplier of specialized nano-layers for LSP and electromagnetic shielding applications).

As part of the work, electromagnetic and conductivity measurement techniques of CNT nonwoven fabrics mats have been developed, and electrical measurements and analysis have been carried out. Good correlation between model and empirical results for aircraft EMI/HIRF requirements has been demonstrated. Direct conductivity measurements and eddy current measurements to calculate sheet resistance have been carried out. Various structural criteria and sample configurations for LSP protection incorporating CNT mats have been explored. The effects of surface treatments on CNT mats to promote adhesion to composite surfaces have been investigated, including mechanical properties testing.

According to the findings, Multi-walled CNT mats may not be conductive enough for a hybrid solution with Cu mesh for lightning strike protection of aircraft composite structures. However, single-walled CNT mats show better potential. The tested CNT mats meet aircraft electromagnetic shielding requirements for EMI and HIRF.