Papers by Keyword: Adhesion

Abstract: Surface protection by hydrophobic impregnation and surface coating are widely used for concrete bridges located at coastal area in Japan. This paper deals with the improvement of adhesion between surface coating and hydrophobic impregnated concrete by different types of silanes and by invastigating surface treatment methods. As a result, adhesion between hydrophobic impregnated concrete and epoxy-based surface coating were improved by applying abrasive paper, portable electric grinder, solvent or diluted hydrochloric acid treatment. Especially, using portable electric grinder gave a remarkable improvement to the adhesive property. Also, hybrid-surface protection system consisting of surface coating and hydrophobic impregnation was discussed to prevent blistering.

Abstract: Efficient use of adhesion between wheels and rails involves a good knowledge of this phenomenon, in order to equip the vehicle with adequate facilities and systems that protect the vehicle and the rail. The loading of the vehicle's axle with dynamic loads in vertical and horizontal planes, are to be developed in the area of contact, both normal stress and shear distributed stress, their sum giving the friction force and the moment of pivoting friction (spin). This makes the wheel-rail contact problems take the two aspects of the study, namely the problem of normal and tangential contact issue. The normal contact problem involves regular geometric shape bodies, determining the size of the resulting contact surface, the distribution of the normal contact pressures and the relationship between the proximity of the bodies and the normal contact force. Solving the problem of the tangential wheel-rail contact is about to establish the correlation between the creepage, normal contact forces and friction forces, and also the ratio between the adherent contact surface and the nominal contact surface where the creepage ocurs.

Abstract: Adhesion assessment between concrete layers with the use of the non-destructive ultrasonic pulse velocity (UPV) method has been described in the article. Two-layer concrete elements, obtained by drilling the core from a large size multilayer element, were the object of testing. The ultrasonic wave velocity of the element and the materials of which its layers were made were assigned for each element. On that basis, the comparative velocity i.e. the velocity at which an ultrasonic wave going through the boundary surface of layers wouldn’t cause any change in the velocity, was determined. The ratio of the two velocities has been compared to adhesion values obtained through the semi-destructive pull-off method. It was revealed that when the ratio of the ultrasonic wave velocity of the element to comparative velocity increases, the pull-off adhesion value also increases.

Abstract: To improve the adhesion between high-performance polyester fabric and silicone, the cold plasma technology was employed in this paper. And the process was optimized through orthogonal test. The changes in the surface morphology of high-performance polyester fabric processed by cold plasma technology were observed. And the mechanical property of the silicone layered with the fabric was also measured. The optimum process for increasing the roughness of the fiber surface but keeping its strength are 3min of treatment time, 80W of power output and 30Pa of gas pressure. The strength and the modulus of the silicone layered with the fabric processed by cold plasma technology can be increased by 8.61% and12.03%.

Abstract: Magnetron sputtering techniques was used to deposit TiN, TiO₂ single layer and TiN/TiO₂ multilayer coatings on 316L stainless steel (316L SS) substrates. The crystallinity, surface topography and roughness parameters of uncoated (316L SS) and coated specimens were examined. The anti adhesion and antibacterial behavior of S.aureus (gram (+) ve) and E.coli (gram (-) ve) strains on uncoated and coated substrates were determined by live/dead staining using epifluorescence microscopy. Results demonstrate that the coated samples undergo drastic reduction of bacterial adhesion and negligible effect of antimicrobial activity. Further, coated substrates exhibit less platelets activation than that of uncoated substrates.

Abstract: Asphalt mix durability is one of the most important aspects if looking on longer lifetime of pavement structures. It is influenced by several factors whereas one of the most important is moisture susceptibility and the quality of adhesion between bitumen binder and aggregateparticles. If the coating by the bitumen is not fully provided or is affected by strongly hydrophilic aggregate type which easier creates bonds with more polar water then it is immediately attacking the aggregate surface and leads to stripping effects – ongoing loss of bitumen-aggregate bonds, mix cohesion problems, etc. With respect to improve adhesion quality different additives (surfactants) are used, whereas two factors might be critical for them: 1) thermal stability of the additive used in bitumen stored for several days at elevated temperatures; 2) bitumen ageing and the effect on additive activity. Both aspects have been studied as a key objective of an ongoing research looking fora suitable laboratory procedure for simulating the thermal stability and assess the remaining activity of the additive. Further asphalt ageing impact on moisture susceptibility is evaluated by changed ratios of indirect tensile strength values for unaged and differently aged test specimens. Results for one type of mix and different aggregates with application of straight-run bitumen 50/70 and 4 different types of adhesion promoters are summarized in the paper.

Abstract: The tensile test operating in a SEM chamber was applied to investigate the adhesion behaviour of the oxide scale on AISI 441 stainless steel used as interconnect in solid oxide fuel cells (SOFCs). The samples were prepared by aligning the final polishing directions parallel and perpendicular to the tensile loading. The samples were oxidised in water vapour and synthetic air at 800 °C. Changing the final polishing direction from parallel toperpendicular to the loading direction caused the spallation ratio to be increased and reduced the strain initiating the first spallation. Adhesion energiesof scales on the studied samples were in the range of 159-384J.m^–2.

Abstract: Bonding has experienced an enormous expansion in the various applications during the last few years in the field of material joining, due to which it is classified as a new joining technology, although it is, in fact, very old. Compared with the conventional joining methods (riveting, screwing and welding), bonding provides a new material combination possibilities and it allows us to obtain special shapes and properties, which can not be formed by conventional methods. To create a high-quality bonded joint, it is important to wet the bonded surface very well wetted by a wetting liquid. The wettability of the material is characterized by a contact angle of wetting, by which the surface energy is subsequently determined. For a high quality of the joint, the bonded material must have higher surface energy than the witting liquid (adhesive) [1-3]. This paper describes the effect of plasma surface treatment on the surface properties (surface energy, microhardness) of low-density polyethylene (LDPE) and high-density polyethylene (HDPE), and also on the final strength of bonded joints. The measured results indicate, that plasma surface treatment is very effective tool for improvement of surface properties and strength of bonded joints of HDPE and LDPE. The strength of bonded joints after plasma surface treatment was increased up to 350 % compared to untreated material. A similar trend was observed even for surface energy and microhardness of materials.

Abstract: Recently the laser beam treatment is more and more in common practice. The fields of use are very diverse. One of these fields of activity is removing of pollutions from a surface and preparation of it before the next stage of treatment. In the paper are presented the results of experimental research which were conducted in the aim of assessment of effects after cleaning of AISI 4130 steel by laser beam. The indicator of process quality was surface free energy (SFE) which is well known indicator in the operation where adhesion is very important. To its assess the measurement of wettability angle is required. After the experiment the results show that it is possible to improve the energetic state of the surface, thus the better preparing of surface before activity when the good adhesion properties are needed than in the case of traditional manner of treatment.

Abstract: The paper presents the main methods of surface free energy calculation of solids based on the contact angle measurement. The basic of splitting the surface free energy into components as well as interactions at the solid-liquid boundary phase considered while developing calculation models were presented. Basing on test results of surface free energy of 0H18N9T stainless steel, the relation between the method of surface preparation and the surface free energy were shown. The analysis focuses on change of the polar part. Differences between methods were indicated and it was pointed that skipping the polar component in analysis of adhesive joints strength results in deterioration of prediction model.