Repair of lightning strike protection coatings on thermoplastic CFRP using low-pressure cold spray

Carbon fiber reinforced polymer (CFRP) is a composite material extensively employed as a metal alternative and primary structural component in modern aircraft. However, the inherent high electrical resistivity of the polymer matrix poses a significant risk of damage from lightning strikes. Recently, cold spray has emerged as a promising approach for metallizing CFRP for lightning strike protection (LSP), offering advantages such as high-speed coating production and adaptability to various product sizes. Furthermore, cold spray presents potential for on-site repair of lightning-damaged LSP coating. This study explored the feasibility of using low-pressure cold spray to repair LSP coatings on thermoplastic CFRP, particularly in areas where lightning strikes caused fractures in the LSP coating and exposed the CFRTP surface. The results indicated that aluminum coatings could be effectively deposited across the entire specimen, including both exposed CFRTP regions and areas retaining the original coating. Subsequent lightning strike tests verified the LSP performance of the repaired coatings.