An enhanced surface treatment for effective bonding of 7075-T6 aluminium alloys

Abstract

ABSTRACT This study research focuses on optimising adhesion through surface treatments on 7075-T6 aluminium alloy substrates using a chromium-free protocol. The treatment involves acetone degreasing, NaOH etching, and sulphuric acid-based solution etching. Wettability analysis and scanning electron microscopy were used to characterise the treated surfaces, highlighting the effectiveness of the proposed protocol. The proposed etching protocol was then applied to aluminium alloy substrates, and fracture surfaces corresponding to each treatment were compared. Mechanical testing, specifically double cantilever beam (DCB) experiments, assesses the fracture energy of bonded assemblies in mode I. The results demonstrate that the sulphuric acid-based treatment significantly improves the surface characteristics, leading to enhanced adhesion and optimal fracture energy in bonded aluminium assemblies.