Papers by Keyword: Surface Pre-Treatment

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Authors: Chiara Mandolfino, Enrico Lertora, Carla Gambaro
Abstract: This paper presents a systematic investigation of the influence of sandblasting pretreatment parameters on the surface roughness and mechanical characteristics of adhesive-bonded joints. The preliminary surface treatment in a bonding process has two important aims: first of all, it eliminates contaminants (dust, grease, humidity and corrosion products) which can modify the wettability of the substrate, then it increases surface roughness and, consequently, the contact area between substrate and adhesive, creating a mechanical interlocking that maximizes adhesion. To enhance the strength and avoid the de-adhesive failure of the joint, it is therefore advisable to increase the contact substrate-adhesive by a mechanical treatment of sanding, grinding or preferably sandblasting, usually considered one of the most effective methods to control the desired level of surface roughness and joint strength. This process, apparently easy to manage, is controlled by a great number of operating parameters, which all contribute to creating a good result. With the aim of evaluating the influence that some of these parameters have on the mechanical characteristics of adhesive-bonded joints, an experimental campaign was carried out. In particular, a steel substrate, an epoxy adhesive and various types of sand, different in nature and granulometry were used. The variable parameters for the execution of blasting are sand, impact angle and pressure. The assessments departed from an investigation into their effect on surface roughness and thereafter the mechanical properties of the bonded joints were analyzed.
Authors: Franz Xaver Wirth, Alexander N. Fuchs, Philipp Rinck, Michael Friedrich Zaeh
Abstract: Friction Press Joining (FPJ) is a suitable method for producing composites of aluminum and thermoplastics in lap joint configuration, which is based on modified Friction Stir Welding (FSW). During the joining process, a rotating cylindrical tool is pressed onto an aluminum surface. The resulting friction generates heat that is conducted to the bonding zone, leading to localized softening of the thermoplastics. In combination with the tool’s axial force and a suitable pre-treatment of the aluminum surface, a resilient composite compound is created. This paper presents the results of a surface pre-treatment of aluminum using laserradiation. The textures are essential for a strong connection, as they can significantly influence effective joining mechanisms, such as microscopic and macroscopic form fit. The experiments were carried out using different surface treatments by means of a single-mode laser for joints of aluminum (EN AW-6082 T6) and glass fiber reinforced polyamide (PA6 GF15). The aim of the study was an increased understanding of process behavior and joining mechanisms. The shear strength could be increased by 40 % compared to previous studies with the presented laser surface treatment.
Authors: Georg Bockmair
Abstract: While chromates as anti-corrosion pigments in primers and wash primers have disappeared in most industries, there are still quite a lot of chromated paints used in the aircraft industry. Intensive efforts to develop alternative pre-treatments to chromate conversion coatings and to chromic acid anodization have begun. The intention of this report is to give an overview of the state-of-the-art techniques about such pre-treatment/coating systems of aluminium for aircraft maintenance, which are in accordance with the latest environmental policies. The objective is to evaluate the combination of surface pre-treatment and paint as a whole.
Authors: Min Seok Moon, Kee Do Woo, Myeong Han Yoo, Chan Won Kwak, Jin Won Han
Abstract: Nowadays, many economist and scientist worried for sharply increased to fuel consumption. Developed and developing countries investigation new energy system. It is base on the low emission gas, high energy efficiency, permanence and cogeneration. Specially, transportation system has restricted to system’s total weight. It is concern with light weight offer to increase to performance by itself. And give to other benefit that reduce to oil consumption, improved fuel economy, engine downsizing and increased to Market-value. Fuel cell is one of the new energy systems for next generation. Normally, fuel cell is consisting of bipolar plate, MEA (Membrane Electrode Assembly) and GDL (Gas Diffusion Layer). Conventional bipolar plate material was applied Graphite. Graphite has very weak for external shock, machining process is not easy, and the main problem is that the graphite material supplied by oxidizing and reducing agent composition of the gas leak comes. Thus, by this reason, the manufacturing cost is increased. In this study, to replace the graphite material was selected as a metal material. In this experiment, STS304 austenite base stainless steel is used. This study was based on the metal material’s corrosion behavior observed with 2 type’s surface pretreatment on the STS304 with similar PEMFC operating condition. Experimental results, As-Polished condition has good corrosion resistance better than As-Received condition. It was concerned with passivation layer.
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