Papers by Keyword: Adhesion

Abstract: In this research new data on the effect of zirconium as an ingredient of the ionic-plasma (Ti, Zr)N coating which is spread on the alloy VK10 KS was obtained. It was found that the introduction of zirconium into the coating composition led to an increase in nanohardness by 23 % up to 38500 MPa and in Young’s modulus – by 67 %, which indicated an increase of energy of atomic bonds and in strength of materials. Also, it led to an increase in an antifriction ability and decrease in the friction constant of the coating up to μ = 0,07, a satisfactory adhesive strength of coating, i.e. in general improved the service features of the whole alloy.

Abstract: The topic of this research work was to demonstrate the feasibility of a 3D-MID concept using injection molding technique and investigate the effects of two weld line types on the structure and mechanical properties such as tensile, flexural strength and morphology. In order to obtain more understanding of the bonds between polymer and metals, two different polymer bases of polyphthalamide (PPA) with the same type and amount of filler content were produced by injection molding at the different processing conditions. A mold was designed in such a way that weld and meld line can be produced with different angles by changing as insert inside of the mold. The mechanical properties such as stiffness, tensile strength and flexural strength were determined in tensile and flexural tests, respectively. The results showed in line with the expectation of high reduction on mechanical properties in area where weld/meld lines occurred. The result of tensile test was clearly seen that weld and meld line showed a considerable influence on mechanical properties. The reduction in tensile strength was approximately 58% according to weld line types, whereas in flexural strength was approximately 62%. On the other hand, the effect of the injection times and mold temperatures on the tensile strength were marginal.

Abstract: An alumina/glass composite was examined for use as a high-temperature ceramic adhesive for bonding of 96% alumina bodies. Four compositions of alumina and glass, 90:10, 80:20, 60:40, and 40:60 by wt.% were studied, referred to here as A, B, C, and D, respectively. Rectangular bend bars were produced from compositions A-D by die pressing. Two half-sized bend bars of 96% alumina were bonded together using pastes produced from compositions A-D. The sintering shrinkage, the phase analysis, the flexural strengths, and the fracture surfaces of the sintered bend bars were examined. The XRD analysis showed a decrease in the alumina and an increase in mullite as the glass content was increased. The dilatometric results found that the onset temperature for sintering shrinkage decreased as the glass content was increased. Composition C was found to have the highest flexural strength of 94 MPa, however the flexural strength of the adhesive joint sample, was only 36 MPa. Composition D had the lowest flexural strength of 43 MPa, but it had the highest flexural strength of the adhesive joint at 61 MPa. The increased adhesive strength of composition D could be due in part to penetration of the excess glass phase into the 96% alumina body. Therefore the flexural strength of the pure compositions alone could not be used to reliably predict the adhesive bond strength. The fracture surfaces of the adhesive joints showed increasing uniformity as the glass content increased, which indicated stronger adhesion.

Abstract: PC film has some shortcomings such as low surface energy and strong rigidity. In order to improve the impact strength and adhesive properties of PC film, UV curing coating which was used on the surface of the PC film achieved good results. However, the combination between the UV curing paint-PC composite membrane had not been explained clearly. In this paper, we analyzed the structure of UV curing varnish oligomers. Fourier Transform Infrared Spectroscopy (FTIR) 、X-ray Photoelectron Spectroscopy (XPS) and Liquid Chromatograph Mass Spectrometer (LC-MS) were used to characterize. Through the experiment, we had achieved 4, 4’ -Isopropyliden-edicyclohexanol(HBPA) and Phthalic acid . The existence of the two substances explained the reason why the lacquer had good adhesion, and the result also laid the foundation for the the characterization of the molecular structure about the film later.

Abstract: In the present study, a surface pretreatment method consisting of KOH etching followed by oxide thickening in boiling water was used to improve the corrosion and adhesion resistance of the coating. The coating morphology on non-pretreated and pretreated Al substrates was characterized by means of scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle measurement. FT-IR spectra was obtained by Fourier transform infrared spectrometer. The corrosion resistance of the coating in 3.5 wt.% NaCl solution was evaluated with potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques. The adhesion resistance of the coating was tested using ISO-2409 standard. Results show that KOH etching followed by oxide thickening in boiling water can effectively improves the corrosion resistance and durability of the coating. Besides, this surface pretreatment method can also improve significantly the adhesion resistance of the coating.

Abstract: In the present study, a thick, uniform and crack-free sol-gel coating embedded with Al₂O₃-CeO₂ nanoparticles was successfully synthesized and deposited on aluminum alloy AA6061 by spin coating method. The coating morphology was characterized by using a scanning electron microscopy coupled with electron diffraction x-ray spectrometer (SEM-EDX), an atomic force microscopy (AFM) and water contact angle measurements. FT-IR spectra were obtained using a Fourier transformation infrared spectrometer. The corrosion resistance of this coating in 3.5 wt.% NaCl solution was evaluated with electrochemical methods including potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The stability of the corrosion resistance of this coating was evaluated by immersion in 3.5 wt.% NaCl solution and by exposure to the UV radiation condition. In addition, the adhesion resistance of the coating was also assessed. SEM and AFM results showed that Al₂O₃-CeO₂ nanoparticles dispersed uniformly in the room temperature vulcanized (RTV) silicon rubber matrix and formed a thick and crack-free coating. Both polarization and impedance results reveal that CeO₂-Al₂O₃ nanoparticles embedded silicon rubber coating can improve the corrosion resistance of the AA6061 alloy by more than three orders of magnitude. Meanwhile, the corrosion resistance of this coating was found to be stable under immersion in 3.5 wt.% NaCl solution and UV exposure conditions. However, excessive content of CeO₂ nanoparticles in the coating made the coating morphology porous and decreased the thickness of the coating, which resulted in the decrease in the corrosion resistance of the coating.

Abstract: Behavior of the material adhered to the cutting edge of a cermet insert was evaluated based on the profile of the machined surface in continuous turning of an austenite stainless steel SUS304. Height of the adhesion material decreased rapidly with increase of the cutting speed from 10m/min to 20m/min. The behavior of the adhered material was more stable than we expected. The adhered layer near the cutting edge was very stable, while the growth or breakage of the adhered material happened on the surface of the stable layer.

Abstract: The presence of Robots in all engineering industries and commercial applications is tremendously growing day by day. Considering this there is a need to implement the robotic principles, which cannot be applicable to the human beings directly. One of the essential areas that lead to complications is maintenance and inspection of large vertical structures with autonomous systems; still it is an unsolved problem for the people doing research on this area. It is a challenge for mobile robots to climb a vertical wall primarily due to requirements for reliable locomotion, high maneuverability, and robust and efficient attachment and detachment. A large number of different robots exist which are able to navigate on buildings, ship hulls or other human-made structures, but most of these systems are practically limited to special situations or applications. It may be due to the design or physical factor that has been considered during the design of robotic system. While considering these issues a lot of researches state various principles and design aspects for maintenance and inspection purposes. Based on these facts, this article discusses the different methods for climbing robots and points out specifically the recent adhesion method for concrete vertical wall climbing. It also discusses about the design characteristics, practical challenges against the execution on vertical structures and suitable valid fields.

Abstract: In order to exploit full potential of hybrid materials, it is necessary to develop optimized load-dependent component designs, new manufacturing processes and joining technologies. Structural integrity concerning the interfaces between the single materials of the hybrid component poses a key factor to success. In this case, adhesion often constitutes the limiting factor for the maximum transferable load. In this investigation, a load-oriented innovative concept to increase the structural integrity of hybrid plastic-metal parts was developed. Local mechanical undercuts on the metal surface were created to generate an additional mechanical interlocking effect between the join partners. The aim is to find the best surface structure geometry to enhance mechanical bonding. Therefore, metal samples were structured by a new process and transferred to hybrid specimens by injection molding. For comparison, specimens with adhesive bonding (epoxy resin) of metal and plastic were prepared. The join partners aluminum AlCuMg1-2017 and PA6 as well as PA6GF30 were investigated. The evaluation of an increase in the structural integrity was determined using tensile tests. A significant improvement in joint strength compared with direct joining using adhesive bonding was achieved.

Abstract: In cold extrusion of aluminum alloys adhesive wear can be prevented by an excessive lubrication of the process. While this causes additional process steps also environmental risks have to be addressed. Hence, dry metal forming, i.e. avoiding lubrication by means of coatings and topography modifications is highly desirable. In this paper first results concerning the behavior of tailored surfaces under dry metal forming conditions for pure aluminum are presented. Different surface treatments (laser polishing and Mo₂BC coating) of the tool steel AISI H11 are tested in a compression-torsion-tribometer under conditions adapted from cold extrusion. Normal stresses six times higher than the initial yield stress of the tested workpiece material pure aluminum (AA1050-O) are applied. Furthermore, a strategy for the characterization of aluminum adhesions to the tool is introduced. The influences of different topographies and the presence of a coating on the loss of material due to adhesive wear are investigated.