Papers by Keyword: Bonding

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Authors: Andreas Schäfert, Hartwig Wiesmann
Abstract: The publication reviews recent applications of 172nm excimer radiation in bio-electric fields. It shows the broad field which already profit from the technology and also illustrates possible potentials. The principle of erasing static electricity from polyimide surfaces is explained as one application. The effect as a function of the dose is presented both for positive and negative charge and typical materials.In addition the VUV cleaning mechanism with 172nm excimer radiation is demonstrated by the mass spectroscopy of contaminations on the surface of a Si wafer.Surface energy changes of polyamides, glass and metal as a function of dose are presented as well as the change of the contact angle of water on the surface.Another application of surface energy enhancement is the polymer microchip production. Due to the surface activation, the bonding strength for the PMMA-Si combination is significantly enhanced. The results are presented in comparison to other surface treatment methods.Another presented application which profits from the surface activation is adhesive-free coupling. The mechanism of this application is explained and the adhesion strength as a function of material combination is presented. For 2 typical applications, the bonding strength is shown as a function of applied dose. A glance at other applications and an outlook is given as well.
Authors: Simon Hehl, Till Vallée, Thomas Tannert, Yu Bai
Abstract: Joining timber structural elements using mechanical fasteners goes against the anisotropic and fibrous nature of the material. Adhesive bonding is by far better adapted, since it permits a smoother load transfer. However, the strength prediction of adhesively bonded wooden joints is difficult brittle nature of the adherends, the complex stress distribution as well as the uncertainties regarding the associated material resistance. As a contribution to help close this research gap, the authors have carried out experimental and analytical investigations on adhesively bonded double lap joints composed of timber. This paper describes the experimental and numerical results and suggests a probabilistic method for the strength prediction of joints composed of brittle adherends and adhesives. The method considers the scale sensitivity of material strength modelled using a Weibull statistical function, and considers both the statistical variation and the size effect in the strength of the material. The probabilistic method presents a mechanical explanation for the increased resistance of local zones subjected to high strain or stress peaks.
Authors: G.İ. Öztürk, H.T. Vakos, W. Voelter, A. Taralp
Authors: M.P. Zanni-Deffarges, Martin E.R. Shanahan
Authors: Hotaruko Sugimura, Yasuyuki Kaneno, Takayuki Takasugi
Abstract: The site preference of ternary additions in Ni3X-type GCP compounds was determined from the direction of solubility lobe of the GCP phase on the experimentally reported ternary phase diagrams. In Ni3Nb (D0a), Co and Cu preferred the substitution for Ni-site, Ti, V and W the substitution for Nb-site, and Fe the substitution for both sites. In Ni3V (D022), Co preferred the substitution for Ni-site, Cr the substitution for both sites, and Ti the substitution for V-site. In Ni3Ti (D024), Fe, Co, Cu, and Si preferred the substitution for Ni-site, Nb, Mo and V the substitution for Ti-site. The thermodynamic model, which was based on the change in total bonding energy of the host compound by a small addition of ternary solute, was applied to predict the site preference of ternary additions. The bond energy of each nearest neighbor pair used in the thermodynamic calculation was derived from the heat of compound formation by Miedema’s formula. The agreement between the thermodynamic model and the result of the literature search was excellent. Both transition and B-subgroup elements have two possibilities, i.e., the case of substitution for Ni-site or the case for X-site, depending on the relative value of two interaction energies.
Authors: Qiang Lv, Ming Xiang Chen, Hui Cao, Zhi Yin Gan
Abstract: An effective method was used to bond carbon nanotubes onto metal electrodes by induction heating process. A good contact between carbon nanotubes and metal electrodes was formed. The contact resistance can be reduced to approximate 95% after induction heating process. Because the induction heating process will selective occur on the structures with high relative permeability and low electrical resistivity, this method could be utilized to realize large scale localized bonding.
Authors: Basil R. Marple, R.S. Lima, H. Li, Khiam Aik Khor
Abstract: There is an ongoing effort to improve the quality and performance of orthopedic implants. Part of this work involves the development of coatings suitable for use in the human body and having properties and bio-performance characteristics better than those of existing materials. The present study focused on developing thermal spray titania coatings engineered to have a bimodal structure consisting of a major fraction of micron scale dimensions within which were dispersed zones of nanostructured material. The coatings were found to exhibit much stronger adhesion to Ti-6Al-4V substrates than conventional hydroxyapatite coatings and to possess excellent crack propagation resistance characteristics. Cell culture studies indicated that human osteoblasts attached and proliferated well on the coating surface. The surface nano-features and nanostructured zones in the coating are believed to play an important role in the improved bonding, mechanical properties and bio-performance.
Authors: Rong Peng, He Ping Zhou, Xiao Shan Ning, Yuan Bo Lin, Xu Wei
Authors: Chang Tian Huan, Dan Yu Jiang, Ge Ming Liu, Qiang Li
Abstract: There are many bonding methods of the ceramic sintered body, such as diffusion bonding, glass bonding, and reports in this regard are not difficult to see. But the solid electrolyte zirconia ceramic bonding in NOx sensor is rarely reported. Here we use zirconia and aluminum-silicon glass together to bond zirconia ceramic sintered body, and tested the electrochemical performance with AC (alternating current) impedance spectroscopy, EMF (electromotive force) of the adhesive layer. The results indicates that the the electrochemical performance is good.
Authors: Mrityunjay Singh, Michael C. Halbig
Abstract: Robust bonding and integration technologies are critically needed for the successful implementation of silicon carbide based components and systems in a wide variety of aerospace and ground based applications. These technologies include bonding of silicon carbide to silicon carbide as well as silicon carbide to metallic systems. A diffusion bonding based approach has been utilized for joining of silicon carbide (SiC) to silicon carbide sub-elements for a micro-electro-mechanical systems lean direct injector (MEMS LDI) application. The objective is to join SiC sub-elements to from a leak-free injector that has complex internal passages for the flow and mixing of fuel and air. A previous bonding approach relied upon silica glass-based interlayers that were non-uniform and not leak free. In the newly developed joining approach, titanium foils and physically vapor deposited titanium coatings were used to form diffusion bonds between SiC materials using hot pressing. Microscopy results show the formation of well adhered diffusion bonds. Initial tests show that the bond strength is much higher than required for the component system. Benefits of the joining technology are fabrication of leak free joints with high temperature and mechanical capability.
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