Search results for "Surface Treatment"
showing 10 items of 29 documents
Laser surface treatments for adhesion improvements of aluminium alloys structural joints
2007
Abstract Laser technology is proposed as a friendly alternative treatment to chemicals involved in conventional prebonding adherend treatments. Aluminium alloy 2024 substrates were laser treated with different beam diameters and energy densities, and bonded using a structural epoxy adhesive. The influence of irradiation conditions on adherends morphology and adhesive joints’ fracture energy was investigated. On the basis of different morphologies observed, an explanation of the effect of the surface treatment upon joint mechanical behaviour is attempted.
Mechanical behaviour and failure modes of metal to composite adhesive joints for nautical applications
2010
In this paper, the influence of several parameters on the mechanical behaviour and failure modes of hybrid bonded joints aluminium/composite was investigated. Particularly, the effects of metallic surface condition, adhesive properties and thickness on single-lap joint resistance were analysed. To these aims, two adhesives were used and, for each adhesive, two different adhesive thicknesses (0.5 and 1.5 mm) have been investigated. Furthermore, two sets of joints for each adhesive kind and thickness were investigated: the former was obtained using aluminium blanks which were previously mechanically treated with sandpaper (P60) and the latter using aluminium treated with sandpaper and with pr…
Pre-Stressed Sub-Surface Contribution on Bulk Diffusion in Metallic Solids
2011
Our recent modelling works and corresponding numerical simulations realized to describe the UO2 oxidation processes confirm the theory showing that an applied mechanical strain can strongly affect the local oxygen diffusion in a stressed solid. This result allows us to assume that stress field, previously applied at the surface of a metallic sample on several microns, will delay the degradation during its oxidation. Considering this hypothesis, we implemented a FEM simulation code developed in our laboratory to numerically investigate some different stress fields applied on a sample sub-surface, that might significantly modify the volume diffusion of oxygen during the oxidation process. The…
Adhesive joining of Aluminum AA6082: the effect of resin and surface treatment
2009
Abstract In this work the effects of both the substrate surface condition and the adhesive properties on single-lap aluminium joint resistance were analysed. The aluminium sheets were mechanically treated with two abrasive surfaces evaluating the induced roughness; four different resins were used in adhesion tests. Moreover, wettability tests were performed in order to evaluate the effect of the above-mentioned parameters on the substrate/adhesive interaction. A design of experiments was defined in order to quantify the effect of the considered factors and their correlation.
Effects of anodizing surface treatment on the mechanical strength of aluminum alloy 5083 to fibre reinforced composites adhesive joints
2021
Abstract In this study, the anodizing process based on the use of tartaric sulfuric acid solution (TSA) was carried out on metal substrate to evaluate for the first time its effect on the adhesion strength and corrosion resistance of aluminium alloy (i.e., AA5083) to fibre (i.e., basalt or glass) reinforced composite adhesive joints for nautical applications. Furthermore, some TSA anodized samples were soaked in a NaOH solution to investigate the influence of this post-immersion step on the joint performances. With the aim to improve the fibre-matrix adhesion in the composite substrate thus further increasing the overall mechanical response of the joint, glass and basalt fibres were treated…
Efficiency enhancement of organic light emitting diodes by NaOH surface treatment of the ITO anode
2009
Abstract Organic light emitting diodes (OLEDs) based on tris-(8-idroxyquinoline)aluminum (Alq 3 ) with enhanced efficiency are reported here. This is obtained by improving the charge carrier balance, through a preliminary NaOH surface treatment of the indium tin oxide (ITO) anode, in order to decrease its work function and, consequently, reduce the hole injection. The obtained devices exhibit a 1.36% external quantum efficiency and a 1.2 lm/W power efficiency at a current density of 60 mA/cm 2 . These values are more than double as compared with those of identical reference devices fabricated without the preliminary NaOH surface treatment.
Surface investigation of plasma HMDSO membranes post-treated by CF4/Ar plasma
2002
Fluorination treatment has been performed on polysiloxane membranes using a plasma glow discharge of a gases mixture CF4 and argon (plasma enhanced chemical vapor deposition). Atomic force microscopy, XPS analyses and contact angle measurements have been undertaken to explain the surface transformation and behavior, which strongly depend on the morphology, the composition and the hydrophilic/hydrophobic character of the plasma-polymerized initial membranes. Main result is that fluorination, which leads to hydrophobic membranes, has a more relevant effect on amorphous silica-like membranes than on polymer-like ones, according to their chemical composition whereas the plasma surface reaction …
TRITIUM - A Real-Time Tritium Monitor System for Water Quality Surveillance
2018
In this work the development results of the TRITIUM project is presented. The main objective of the project is the construction of a near real-time monitor for low activity tritium in water, aimed at in-situ surveillance and radiological protection of river water in the vicinity of nuclear power plants. The European Council Directive 2013/51/Euratom requires that the maximum level of tritium in water for human consumption to be lower than 100 Bq/L. Tritium levels in the cooling water of nuclear power plants in normal operation are much higher than the levels caused by the natural and cosmogenic components, and may easily surmount the limit required by the Directive. The current liquid-scint…
Charge carrier transport mechanisms in CdZnTe detectors grown by the vertical Bridgman technique
2016
In this work, we report on the results of electrical characterization of CdZnTe (CZT) detectors, with gold electroless contacts, grown by the boron oxide encapsulated vertical Bridgman technique (B-VB), currently produced at IMEM-CNR (Parma, Italy). The detectors, with different thicknesses (1 and 2.5 mm), have the same electrode layout: the anode is a central electrode (2 x 2 mm(2)) surrounded by a guard ring electrode. The cathode is a planar electrode covering the detector surface (4.1 x 4.1 mm(2)). Current-voltage (I-V) characteristics were measured at different temperatures in order to study the charge transport and the electrical properties. These detectors were compared with the trav…
Study of a plasma generated in metal surface treatment by laser ablation in air : characterisations of induced radiation and nanoparticules
2015
The interaction of a laser beam of short pulse duration with metallic materials such as aluminum, iron or titanium is characterized by the presence of a high energy and strongly ionized plume (plasma). The aim of this study is to understand the mechanisms involved in plasma, created when laser-target interaction, which lead to the formation of nanoparticles. We would generally consider the dynamic expansion in the air of the plasma plume formed with a nanosecond Nd:YAG laser to specify the conditions of formation of these particles and their morphological and structural characteristics. Thus, this work is divided onto two parts. In the first part, we present the experimental characterizatio…