Papers by Keyword: Bonding

Abstract: The main criteria for evaluation of ceramic products’ properties are strength, structural and mechanical, and thermophysical properties. To produce ceramic composites with a wide range of structural, mechanical, strength, and performance properties depending on application, various additives (flux agents, sintering agents, fillers) and heat treatment processes are used. Studies to determine a rational mixture composition have been carried out. A multipurpose material, comprising particles of the basic chamotte filler (burned clay) with a bonding agent in the form of refractory clay from the Latnenskoye deposit with a field spar fluxing agent, an additional filler made of heat-resistant silicon carbide, and an adhesive component in the form of powdered dextrin, is suggested. According to the combination of its ensured parameters, the obtained ceramic material can be multipurpose. Its degree of porosity and permeability make the material filtering, sound-proofing, and heat-retaining; considering the low density, it can be used as a lightweight construction material.

Abstract: The paper aims to present a finite element model for the bond strength evolution in cold roll bonding processes. To accomplish this, first, the micro-mechanisms taking place along the cold welded joint interfaces are explained. Then, based on the microscopic description of cold welding processes, a bonding interface model is employed to describe the bond formation between the rolled metallic layers. The obtained bond strength is calculated based on the governing parameters of the bonding such as the degree of plastic deformation and the surface cleanness. The numerical simulation given in this paper includes the modelling of joining during cold roll bonding followed by the debonding process in Double Cantilever Beam (DCB) peeling test. Finally, the effects of two important factors on the bond formation, i.e. (1) the degree of plastic deformation and (2) the surface cleanness, are numerically investigated.

Abstract: A relevant technology issue in lost foam casting is preventing the metal penetration appearance on steel and cast-iron mouldings. As a result of the research the appropriate parting model paint compositions with the use of recycling and nanostructured materials were developed. The basic technological characteristics of the developed parting model paint compositions are: relative stickiness due to VZ-6 18...25 s; residual moisture content 1...1.5 %, permeability to gases 40...50 ea. The parting paint effectiveness is determined by defect reduction of the castings on the core blow, uncertainty in geometry, metal penetration, and also the use of available and environmentally friendly molding materials in their composition, that makes the product to be highly competitive.

Abstract: Laser-structured metal surfaces in combination with thermoplastic compression mould processes allow intrinsic hybrid structures with high-strength connections. Suitable process parameters are still to be identified to provide optimised assembly parameters. Therefore, laser structures with different configurations are applied to steel sheets and compressed with textile reinforced thermoplastic composites to manufacture hybrid structures. Laser processing parameters, such as pulse duration or energy as well as laser scanning strategies and therefore structure dimensions are analysed.After manufacturing, specimens are extracted and characterized in single-lap shear tests comparing different configurations to identify boundary conditions for the laser structuring with optimal bonding characteristics.

Abstract: Transient Liquid Phase (TLP) bonding was performed between Mg-AZ31 and Ti-6Al-4V alloys with various bonding temperatures using Cu coatings and Sn interlayers. The bonding parameters such as bonding pressure and bonding time were fixed at 1 MPa and 15 minutes respectively in order to study the effect of bonding temperature on the joint evolution. Bonds made at temperatures of 540, 560, 580 and 600 C showed good bond strength. The obtained bonds were investigated by Electron Probe Micro-analyzer EPMA and showed reaction layers and diffusion zones for all bonds made. The maximum joint shear strength of 78 MPa was obtained for bond made at 580 C. X-ray diffraction XRD and X-ray photoelectron spectroscopy XPS were taken for the fractured surfaces of bond made at 580 C. The analysis of the fractured surfaces found that the reaction layer contains Sn5Ti6 IMC in the titanium side and Mg2Cu IMC in the magnesium side where the fracture occurs at the diffusion zone in the mg side.

Abstract: Sandwich panels made of thin and stiff skins, connected by a thick and soft core are widely used in load-bearing components mainly due to their high strength to weight ratio. To improve the reliability in using sandwich beams, it is necessary to understand their responses under external mechanical and environmental stimuli. This paper investigates the construction of steel-polyurethane-steel sandwich panels and their mechanical properties. Key properties of a sandwich structure are the adhesion between the skins and the sandwich material, and the load transfer from the outer skin to the inner skin. Lap shear specimens were selected to give an indication of the bond strength of the polyurethane to steel, whilst three point bend test specimens were selected to indicate the degree of load transfer between the skins and the bending resistance provided by the sandwich structure.

Abstract: Anisotropic conductive film (ACF), is a lead-free material that is commonly used in fine-pitch interconnect manufacturing to make and maintain the electrical and mechanical connections between the micro-electrodes. A key issue about the circuit conductivity is the deformation, breakage, and number of conductive particles in the ACF packaging. For the field of vision, the Film-On-Glass (FOG) assembly on the glass-side is used to obtain excellent images in experimental observation. This paper utilizes the microscope technology to investigate the bonding properties of the conductive particles, and consider the electrical resistance effects after packaging. The results show the deformation shape, breakage type, and number of conductive particles will be quantitatively affect the electrical performances, and one can measure the area, diameter, and roundness of the deformed particles’ projection in the glass-side view to evaluate the ACF packaging quality.

Abstract: This paper presents a numerical simulation and preliminary experimental investigation of bonding of concrete structures using cement and polymer cement as adhesive materials. The numerical model of concrete plates bonded with the polymer cement is created and subjected to cyclic thermal loading. As a result, the critical stresses are obtained. Also all the necessary materials for carrying out high-quality, fast and inexpensive experimental investigation of the strength of cement and polymer cement bond are prepared. The experimental setup and the first results obtained are also described. The bonding quality of the polymer cement shows satisfactory results under this kind of loading, thus the use of the polymer cement for bonding of concrete structures of different properties is reasonable in the specific fields considered in this study.

Abstract: This paper deal, on example of aluminium alloy beam strengthened by using elements of steel, with theoretical analysis of the possibilities for composite action of beam formed from two materials with considerably different coefficients of thermal expansion. According to authors opinion conclusions lead to clear statement that such structures are possible as well that such solutions could have economical and serviceability sense, especially in field of structural engineering where exposing to temperature changes is limited to relatively small range. In case of aluminium and steel combination, for extreme temperature change used in structural engineering, advantages that are achieved are considerably higher than disadvantages, especially in cases where deformation is dominant condition.

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.