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...

Nanorods grown by copper anodizing in sodium carbonate

Self-organized anodization of copper in 0.1 M Na2CO3 electrolyte was studied in order to obtain nanostructured oxide surface on the metal substrate. Linear sweep voltammetry (LSV) revealed that the most suitable voltage range for anodic film formation is from 3 to 31 V. In this range (except between 3 and 7 V), the oxide is formed as nanorods,...

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...

Fluoride-induced interfacial adhesion loss of nanoporous anodic aluminum oxide templates in aerospace structures

Nanoporous anodic aluminum oxides (AAOs) are used as templates in various technological applications, including load-bearing aircraft structures. But in spite of their popularity, the important aspects that control their (dis-)bonding to an organic coating are not fully understood. To study the mechanisms behind the negative effect of fluorides...

Towards Cr(VI)-free anodization of aluminum alloys for aerospace adhesive bonding applications: A review

For more than six decades, chromic acid anodizing (CAA) has been the central process in the surface pre-treatment of aluminum for adhesively bonded aircraft structures. Unfortunately, this electrolyte contains hexavalent chromium (Cr(VI)), a compound known for its toxicity and carcinogenic properties. To comply with the new strict...

Interface strength and degradation of adhesively bonded porous aluminum oxides

For more than six decades, chromic acid anodizing has been the main step in the surface treatment of aluminum for adhesively bonded aircraft structures. Soon this process, known for producing a readily adherent oxide with an excellent corrosion resistance, will be banned by strict international environmental and health regulations. Replacing...

Adhesive bonding and corrosion performance investigated as a function of auminum oide chemistry and adhesives

The long-term strength and durability of an adhesive bond is dependent on the stability of the oxide-adhesive interface. As such, changes in the chemistry of the oxide and/or the adhesive are expected to modify the interfacial properties and affect the joint performance in practice. The upcoming transition to Cr(VI)-free surface pretreatments...

Morphology and photoluminescence of nanostructured oxides grown by copper passivation in aqueous potassium hydroxide solution

Copper foil was anodized in 1 M KOH at potentials ranging from −400 to −100 mV vs. Ag|AgCl electrode. Cyclic voltammetry showed a distinct peak with a maximum at around −150 mV. For anodizing at −100 and −200 mV, nanowires with diameters of ca. 19 and 24 nm respectively were found to be grown. Moreover, photoluminescence and X-ray diffraction...