Effect of Anodizing on Strength of Carbon-Fibre Aluminium-Laminated Composites

Abstract

Fibre-metal-laminated composites that consist of aluminium and carbon fibre/epoxy was widely use in engineering fields such as in aerospace and civil application. An issue arise for this laminate systems is that aluminium surfaces must be treated to ensure the effectiveness of load transfer mechanism in the interfacial region. In this research, the effect of anodized layer on the aluminium surface towards strength of the carbon fibre-aluminium-laminated composites was studied. Aluminium 6061-T6 was anodized using phosphoric acid as electrolyte and different anodizing voltage to produce different surface morphology. The surface roughness and morphology were determined via Atomic Force Microscopy and its wettability was determined by Static Contact Angle. Then, anodized aluminium was laminated with carbon fibre/epoxy system via vacuum bagging techniques. It shows that the strength of laminated composite with anodized surface increases up to 26% compared to laminates without anodized surfaces. Furthermore, the failure mechanism of laminated composite with anodized surface resulted in partial adhered failure instead of adhesive failure. These show that anodized surfaces contributes to the effectiveness of load transfer mechanism in fibre-metal-laminates composites.

Effect of Anodizing Electrolyte for Structural Adhesives Bonding Study of Aluminium-Carbon Laminates Composites

“…In this study, both phosphoric and sulphuric acid result in an acceptable surface microstructure and morphology,unlike nitric acid which caused cracks on the film as shown in Figure 3(d) and (f). It was stated that increasing the surface roughness of the layer enables the epoxy matrix to penetrate into the irregularities on the surfaces and the pores of anodized surfaces, which generate an effective interlocking mechanism in the interfacial region between the carbon fibre/epoxy and aluminium surfaces [19]. In addition, an extremely smooth surface was unable to create a distinct effect on the surface of the adherent [20].…”