Evaluation of Surface Treatment for Enhancing Adhesion at the Metal–Composite Interface in Fibre Metal-Laminates

Abstract

The paper presents the issues of metal surface treatment in fibre metal laminates (FML) to obtain high adhesion at the metal–composite interface. Aluminium 2024-T3 and titanium Grade 2 were analysed. The metal surface modifications were carried out by mechanical (sandblasting, Scotch-Brite abrasion), chemical (P2 etching, phosphate-fluoride process), electrochemical (chromic and sulphuric acid anodizing), and plasma treatment, as well as the application of sol-gel coatings. In terms of surface geometry, the analysis included roughness and 3D surface topography examination. The morphology was examined using scanning electron and atomic force microscopy. The surface free energy and its components (polar and dispersive) were determined using the Owens–Wendt method. The novelty of this study is the determination of the effect of different surface treatments on the surface free energy, topography, and morphology in terms of the possible appropriate adhesion in fibre metal laminates. Chromic acid anodizing is still the most effective in enhancing the expected adhesion. A suitable technique may be the use of P2 etching of aluminium. It results in low roughness, numerous micro-irregularities, and the presence of porosity. The obtained test results show that the application of sol-gel coating increases the surface free energy and may increase the adhesion.

The Correlation of LVI Parameters and CAI Behaviour in Aluminium-Based FML

“…Nevertheless, one can state that the combination of elastic-plastic metal layers, fibrematrix composite layers and their mechanochemical [9] connection results in a significant advantage for FMLs in terms of CAI strength compared to conventional composites (e.g., [51]). The main reason for that is the high static strength and limitation of rapid buckling of the delamination after impact.…”

“…Among others, to improve the impact resistance of light aerospace structures, fibre metal laminates (FMLs) were introduced in the late 1980s [8]. The supplementation of FRP properties with the presence of metal with different mechanical behaviour [9] allows the limitation of impact-induced damages significantly and raise the amount of absorbed energy [10], which is proven by many studies [11]. To increase the impact resistance and energy absorption ability further, fibre metal laminates are used in some cases as face sheets for lightweight sandwich structures [12,13].…”

Experimental and Numerical Investigation of the Tensile and Failure Response of Multiple-Hole-Fiber-Reinforced Magnesium Alloy Laminates under Various Temperature Environments

“…Fiber metal laminates (FMLs) are a typical composite material consisting of alternating layers of surface-treated alloy laminate and fiber/resin material [ 1 , 2 ]. Based on the hybrid structure, FMLs have outstanding properties of high strength and stiffness, excellent plasticity, fatigue resistance, and corrosion resistance [ 3 , 4 ].…”

Fire Risk of Polyethylene (PE)-Based Foam Blocks Used as Interior Building Materials and Fire Suppression through a Simple Surface Coating: Analysis of Vulnerability, Propagation, and Flame Retardancy

“…It is known that the factors affecting flame retardancy include coating thickness, density, substrates, composite, panel type, and efficiency of formulations [20]. However, the most fundamental factor determining the success or failure of a coating is surface treatment, which is very important as it ensures proper adhesion of the coating to the substrate [21]. Polyhedral oligomeric silsesquioxane (POSS), carbon nanotubes (CNTs), montmorillonite (MMT), graphene nanosheets, and graphitic carbon nitride are known to impart excellent flame retardancy to polymeric materials [22].…”