Papers by Keyword: PVD

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Authors: Ben Niu, Chao Jie Zhang, Xiu Liang Chen, Heng Yu Wang
Abstract: A semi-analytical method to calculate the degree of consolidation of the soilbag filled with mud soil with PVD built in is proposed. First a unit-body model is founded to obtain the low-dimensional solution. Through the successive iterations of the low-dimension solution, the solution considering the situation when the physical or geometry parameters of the model vary is finally obtained. The solution of the rectangular area is obtained by summing solutions of two square area with coefficients set. A lab experiment was done in Liubao test base of Zhejiang institute of hydraulics and estuary to research the consolidation performance of soilbag filled with mud soil buried with PVD. The semi-analytical method and FEM are applied to calculate the lab experiment case. From the comparison among the lab experiment, the semi-analytical method and FEM, it shows that the semi-analytical method calculates a good result of the degree of consolidation of the lab experiment.
Authors: Roland von Bargen, Axel von Hehl, Hans Werner Zoch
Abstract: The continuous miniaturization of products needed e.g. in the automotive or the microelectronics sector requires process chains, which allow the manufacturing of microscopically small components in high quantities. The development of the required processes and technologies is the aim of the Collaborative Research Centre 747 “Micro Cold Forming” of the German Research Foundation. As a necessary step in the manufacturing process chain heat treatment enables the adjustment of the semi-finished micro components to cold forming. Finally, the in-service characteristics of the aluminium components have to be adjusted by precipitation hardening that increases the strength values beyond those which can be achieved by strain hardening. To provide high strength aluminium alloys with an improved thermal stability new alloy concepts and advanced production processes have been developed within the Collaborative Research Centre (CRC). Besides the scandium containing foils made of alloy Al-2Sc, foils of a novel alloy Al-4Zr with approximately 4 mass-% Zirconium has been produced by means of physical vapour deposition (PVD). In contrast to conventional strip casting techniques the PVD process operates with low temperatures, which should suppress premature precipitation during the foil production and ensure the supersaturated solid solution that is a prerequisite for precipitation hardening. Samples of this material were subsequently artificially aged and characterized by ultra micro hardness measurements (UMH), transmission electron microscopical (TEM) analysis and differential power scanning calorimetry (DPSC) to evaluate the applied aging parameters.
Authors: Kyeong Cheol Baek, Chan Yeol Seo, Ki Bok Heo, Yang Soo Kim, Dong Joo Yoon, Byung Il Kim, Kyung Ku Lee, Dong Soo Han
Abstract: Arc ion plating (AIP) is one of the most attractive physical vapour deposition (PVD) method for the industrial manufacture of TiN coatings, owing to a high degree of ionization in the target material and convenient control of the process parameters. The important characteristic of hard coating is the adhesion strength between the coating layer and the substrate. The coating will be subjected to various loads, such as mechanical, thermal load, etc., in practical applications. Therefore, for more than a decade, Ti-based hard coatings have been applied to tools, dies, and mechanical parts because of the enhance lifetime and performance. It is focus on the attractive properties such as high hardness, good wear, and chemical stability. In the present study, TiN monolayer film was prepared at various N2 partial pressures and current by the AIP technique in SACM645 material. The correlation between microstructure and properties of the TiN coating was comparatively investigated by XRD, FE-SEM and AFM. These study carried steadily out improve the adhesion properties and wear resistance of Ti-based coating using pre-treatment of the substrate, insertion of an interlayer, application of multi-layers and adjustment of the process parameters. The main phase FCC TiN displayed (200) orientation in the film with the highest N2 partial pressure. The (111) orientation was observed with decreasing N2 partial pressure. The (200) and (111) textures in the film which was treated 80A arc current were found to be competitive orientations, however stronger arc treated the (200) texture was increased. The multilayer TiN films has possessed high hardness (up to 42Nm) and the best wear resistance among the specimens. These features were attributed to the presence of dense microstructures that were mainly composed of TiN phase around 5.16㎛ thickness, HF1 adhesion and Ra 35㎚ surface roughness
Authors: C. Chokwatvikul, S. Surinphong, C. Busabok, P. Termsuksawad, Siriporn Larpkiattaworn
Abstract: Sintered TiAl alloy with composition of 50 at.% Al and 50at.% Ti are used as target in the PVD cathodic arc system to produce (Ti,Al)N film. The coating conditions are operated using substrate bias voltage and arc current bias of 100V and 70 A, respectively. In addition, the coating time was set at 1.30 h with thru different values of nitrogen gas pressures: 1, 1.5and 2 Pa. After coating the film was characterized for thickness, surface roughness, adhesion, morphology, and phase structure. It was found that phase structures, film thicknesses and adhesion of the films deposited from different nitrogen pressures are not significantly different. However, the micrographs showed that the film prepared by using 1.5 Pa of reactive N2 gas is smoother with less droplets than those film prepared at the other two pressures.
Authors: Branko Skoric, Damir Kakas, Aleksansar Miletic
Abstract: In this paper, we present results of a study of TiN films which are deposited by Physical Vapor Deposition and Ion Beam Assisted Deposition. In the present investigation the subsequent ion implantation was provided with N2+ ions. The ion implantation was applied to enhance the mechanical properties of the surface. The film deposition process exerts a number of effects such as crystallographic orientation, morphology, topography, densification of the films. The evolution of the microstructure from porous and columnar grains to densely packed grains is accompanied by changes in mechanical and physical properties. A variety of analytic techniques were used for characterization, such as scratch test, calo test, SEM, AFM, XRD and EDAX. The experimental results indicated that the mechanical hardness is elevated by penetration of nitrogen, whereas the Young’s modulus is significantly elevated. Thin hard coatings deposited by physical vapour deposition (PVD), e.g. titanium nitride (TiN) are frequently used to improve tribological performance in many engineering applications. Ion bombardment during vapour deposition of thin films, colled ion beam assisted deposition (IBAD), exerts a number of effects such as densification, changes in grain size, crystallographic orientation, morphology and topography of the films. This paper describes the successful use of the nanoindentation technique for determination of hardness and elastic modulus. In the nanoindentation technique, hardness and Young’s modulus can be determined by the Oliver and Pharr method. Therefore, in recent years, a number of measurements have been made in which nanoindentation and AFM have been combined.
Authors: Anja Buchwalder, Rolf Zenker, Erik Zaulig, Jürgen Liebich, Dietmar Leuteritz
Abstract: Due to their typically high hardness, excellent resistance against wear, and their low coefficient of friction, Physical Vapor Deposition (PVD) hard coatings are used on steels for a wide range of tools and components. Currently, however, the potential for wear protection of Al alloy components cannot be exploited. The thin PVD layers tend to collapse and disintegrate due to plastic deformation of the soft base material. Present research is focused on electron beam (EB) surface alloying, using Co-based additives to increase the surface hardness of the Al base material, producing an improved supporting effect for PVD coatings. The influence of different beam deflection techniques and EB parameters on the microstructure and hardness of alloyed layers was investigated. The properties of the duplex composite layers produced are strongly dependent on the thermal stability of the EB alloyed layers (type and amount of intermetallic compounds, coarsening effects) which are affected by the temperature-time cycle of the PVD process. This will be discussed by means of SEM and EDX investigations in correlation with XRD analysis. Measurements using scratch test with increasing load result in critical load values for the combined treatment that are 3 to 5 times higher when compared to only PVD-coated base material.
Authors: Fritz Klocke, Olaf Dambon, Kyriakos Georgiadis
Abstract: The complexity of optical components increases steadily in recent years, while their dimension de-crease. This situation makes the production of state of the art optical components by grinding and polishing very difficult and expensive. However, the technology of precision glass molding can be used to replace these traditional manufacturing methods by a single step replicative process. To achieve economies of scale with precision glass molding, a long molding tool lifetime is necessary. This can only be realized by applying protective PVD coatings on the molding tool surfaces. Well known thin hard coatings like TiAlN or CrN, as well as noble metal coatings are possible candidates. However, practical testing of carious coating-glass combinations in precision glass molding machines is not feasible due to long process times that make such testing very expensive and time consuming. In this work, these coatings are compared with each other and in combination with various glass types by performing oxidation and contact angle tests. The results of these tests are compared to the results of practical tests, in order to determine to which extent such model tests can replace practical testing.
Authors: B. Pelic, D. Rafaja, Patrick J. Masset, H.J. Seifert, L. Bortolotto, Michael Schütze, G. Wolf, I. Loeh
Abstract: γ-TiAl intermetallics are attractive materials for high-temperature structural applications in the aerospace and automobile industries. However, they show environmental embrittlement at elevated temperatures that is mainly related to their low high-temperature corrosion resistance. One way how to improve the high-temperature corrosion resistance is the deposition of protective coatings on the surface of the base material. In this study, samples of a Ti-Al alloy with the chemical composition Ti-48Al-2Cr-2Nb (at.%) were covered by physically vapour deposited (PVD), by metalorganic chemically vapour deposited (MOCVD) and by high-velocity oxy-fuel (HVOF) sprayed coatings. All coatings were based on the Ti-Al alloys and contained different amounts of alloying elements. The corrosion experiments were performed in molten salts containing 75 wt.% Na2SO4 and 25 wt.% NaCl at 850°C up to 336 h. Both, PVD and CVD protected coatings reduced the changes in the mass of the samples over the corrosion time. Still, the formation of TiO2 could not be avoided, as it was confirmed by glancing-angle X-ray diffraction experiments.
Authors: Mirko Sokovic, Leszek Adam Dobrzański, Janez Kopač, Ladislav Kosec
Abstract: The paper presents investigation results of tribological and cutting properties of the coatings deposited with the PVD and CVD techniques on cutting inserts made from the Al2O3 + TiC tool ceramics. Tests were carried out on the inserts made from ceramics, uncoated and PVD or CVD-coated with gradient, mono-, multilayer and multicomponent hard wear resistant coatings composed of TiN, TiCN, TiAlN, TiAlSiN and Al2O3 layers. Substrate hardness tests and micro hardness tests of the deposited coatings were made on the ultra-micro-hardness tester. It was demonstrated, basing on the technological cutting tests of grey cast iron (260 HB), that putting down onto the tool ceramics the thin anti-wear PVD and CVD coatings increases their abrasion wear resistance, which has a direct effect on extending tool life of the cutting edge.
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