Abstract: Resin-based composite materials have been receiving much attention due to their excellent mechanical properties and good designability, and they have also been widely used in aerospace and military fields. As composite materials are further deployed in various fields, defects in them begin to emerge. Unlike conventional metal materials, composite materials cannot be perforated to use bolted joints without compromising their overall performance. The manufacture of composite materials has great uncertainty, and the stability of their performance is difficult to control. Therefore, in practical applications, many parts still need to use traditional metal materials. This brings up a new problem, that is, the connection of composite materials to metal materials. As stated above, if the composite material is bolted, the perforating operation prior to joining will cut the reinforcing fibers resulting in a decrease in the overall performance of the composite. This operation will also cause stress concentration at the opening, further reducing its performance and long-term stability, and there is also the possibility of electrochemical corrosion between the composite material and the metal material. To this end, researchers around the world have begun to focus on the adhesion between the composite materials and the metal materials, using a variety of adhesives as an intermediate layer to join them together. This paper first introduces the development history of resin-based composite materials in practical applications. Then the related theories of designing adhesion systems of composite materials and metal materials are briefly described, from chemical bond connection theory, mechanical interlocking connection theory, surface wetting and adsorption theory, and electric double layer connection theory. Then several common surface pretreatment methods are introduced, including physical pretreatment methods such as sand blasting and abrasion, solvent cleaning, and chemical pretreatment methods such as chemical etching, anodizing, plasma treatment, silane coupling agent treatment, laser treatment. Finally, some ideas for the modification of adhesives are listed.

Key words: surface treatments, composite, adhesion, metal, adhesive