Effect of anodizing electrolyte for structural adhesives bonding study of aluminium-carbon laminates composites

Fibre metal laminates (FMLs) are multi-component materials that utilize metals, fibres and matrix resins. These composite laminates are in demand in the market for their stiffness and rigidity for structural applications. Their strength is highly dependent on the mechanical interlocking mechanism between the metal surface and the composite laminates. Therefore, the metal surface must be well-treated to ensure a good interfacial interaction between the metal surface and the composite laminates. In this research, FMLs were fabricated using aluminium 6061 and carbon fibre/epoxy laminates. The aluminium surface was treated using anodizing techniques and the effects of three different anodizing electrolytes were systematically investigated to obtain the optimum interfacial strength. The surface morphology was characterized using atomic force microscopy and scanning electron microscopy (SEM). The mechanical strength of these laminate systems was characterized using a universal testing machine via tensile and lab shear techniques. It is predicted that different anodizing electrolytes will result in different anodized surface morphologies that will contribute to the interfacial interaction and the strength of FML systems.