Effect of surface treatments on metal–composite adhesive bonding for high-performance structures: an overview

Composite materials are being preferred in automobile, aerospace, naval, and construction applications due to flexibility of design, their high strength to weight ratio, and high fracture toughness. Since the majority of today's structures is hybrid, i.e., made by a combination of metals and composites, the joining of these two remains a big industrial issue. For composite–metal joining, different techniques have been reported such as adhesive bonding, mechanical fastening, and a combination of these, etc. Surface modification of metal, composite, and adhesive are done to improve bonding between them. This paper provides an overview of various surface pre-treatments required on metals, composite and adhesive, the effect of surface treatments on metals and composites, and the strength of joints. In the end, recommendations are provided for the selection of surface treatments for the joining of specific metal and composite.