Preparation of nanocopper particles on Al-Li alloy by salt spray droplets

•A process for producing nanocopper particle with salt spray droplet was described.•Nanocopper particles were found surrounding the vicinity of pits.•The nanocopper particles about 50–200 nm were spherical, pentagonal or rectangle shape.•The reaction mechanism was demonstrated by nanocopper particles’ SEM images with EDS.•Thickness of salt spray droplet film were adjusted deposition and adsorption time.