Effects of Nanoporous Structure of Anodic Films on Adhesive Strength between Aluminum Alloys and Polyamide Resin

Abstract

In this study, the effects of the nanoporous structure of anodic films on adhesive strength between aluminum alloys and polyamide resin were systematically investigated. Alumina films with different dimensions (such as pore density, diameter, and depth) were formed on A6063 aluminum alloys by various anodizing conditions to compare the anchoring effect. The adhesive strength at the interface between the adherend (anodized aluminum) and adhesive (thermoplastic elastomer resin) was evaluated by a method for determining the tensile lap-shear strength of rigid-to-rigid bonded assemblies. The higher pore density and larger pores in anodic films were important factors for improving the adhesive strength and increasing the adhesion interface area and the amount of adhesive impregnated into the pores. After anodizing in phosphoric acid at 60 V and subsequent pore widening, the adhesive strength of aluminum was 17.4 MPa, which was ∼3.5 times higher than that of an aluminum substrate without surface treatment.