Surface engineering of aerospace aluminium alloys: Understanding alloying effects on chemical pre-treatment and sol-gel coating adhesion

The sol–gel process is a chemical surface preparation method based on hydrolysis and polycondensation reactions for enhanced adhesion for metallic substrates in adhesive bonding and coating applications. This paper describes an investigation into the effect of the microstructural complexity of two commonly used aerospace aluminium alloys (AAs...

FEM modelling to predict spatiotemporally resolved water uptake in organic coatings: Experimental validation by odd random phase electrochemical impedance spectroscopy measurements

In this work, a new finite element modelling (FEM) approach is followed to model spatiotemporally resolved water uptake in organic coatings. To this aim, we start from a physical model, where not only Fickian diffusion of water is taken into account but also the adsorption/desorption reaction of water on the polymer matrix. Starting from a...

Scrutinizing the importance of surface chemistry versus surface roughness for aluminium / sol-gel film adhesion

The sol-gel synthesis process is a versatile method used to produce a wide diversity of materials and is being increasingly used as a surface modification method to alter porosity, wettability, catalytic activity, biocompatibility and corrosion performance of underlying substrates. Silane sol–gel films deposited on aluminium and aluminium...

Exploring water and ion transport process at silicone/copper interfaces using in-situ electrochemical and Kelvin probe approaches

In general, packaging materials which encapsulate light emitting diodes (LEDs) and microelectronic devices offer barrier protection against several environmental hazards such as water and ionic contaminants. However, these encapsulants may provide pathways for water and ionic contaminants to reach the metal/polymer interfaces and provoke local...

Effect of organic additives in fluoacid-based Ti and Zr-treatments for galvanized steel on the stability of a polymer coated interface

The bonding properties of zirconium- and titanium-based conversion coatings were evaluated using model conversion solutions of H₂ZrF₆ and H₂TiF₆ with addition of various organic additives (PAA, PVA, PVP). Macroscopic testing techniques such as contact angle and pull-off adhesion measurements were...

Effect of surface roughness and chemistry on the adhesion and durability of a steel-epoxy adhesive interface

This work focuses on the effect of surface roughness and surface chemistry on the initial adhesion strength and corrosive de-adhesion properties of adhesive bonds. The adherend used in this study is a S690 low-alloy steel whereas the adhesive is a 2-component epoxy-amine adhesive (Araldite 2015). The steel surface is subjected to different...