Papers by Keyword: Diamond-Like Carbon (DLC)

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Authors: D. Lusk, M. Gore, B. Boardman, D. Upadhyaya, T. Casserly, M. Oppus
Abstract: A novel technique for depositing thick DLC based films on the inside of cylindrical substrates, like pipes, tubes and valves, has been developed. A plasma enhanced chemical vapour deposition (PECVD) technique has been used to engineer and optimize the above mentioned films for maximum coating performance. Of particular importance is the corrosion and wear resistant qualities of these films. Changes in film chemistry, structure and thickness are attributed to the improved corrosion and wear resistance. Details will be given of the corrosion testing which has taken place, such as exposure to HCL (hot and ambient temperature), NaCl and H2S environments. One such test is a very aggressive sour autoclave test where the film is exposed to an aqueous, organic and gas phase over a 30 day period and no damage to the film was found. In depth details of this sour autoclave test will be shown including photographs of the film before and after testing. Wear testing has also been carried out in dry and wet sand slurry environments where very low coefficient of friction (COF) and wear rates were found. It is believed that this thick DLC based film can increase the component life in applications where internal surfaces are exposed to highly corrosive and abrasive media, in particular the oil and gas industry. Examples of such applications are mud pump sleeves, deep well components, directional drilling, abrasive flow spools, pump barrels and in sour fields (H2S).
Authors: Lânia Auxiliadora Pereira, Marcelo Brison de Mattos, Evaldo José Corat, Vladimir Jesus Trava-Airoldi
Abstract: The martensitic stainless steel X45CrSi93 is widely used in the automotive industry. One way to improve its properties is the deposition of high adhesiveness DLC films, which are well known for their excellent properties such as high hardness, low friction coefficient, chemical inertness, biocompatibility and excellent wear resistance. In this work, the adhesion between substrate and film was studied, by growing silicon interfaces with different deposition parameters. The technique used for growing these films was PECVD pulsed-DC. In order to obtain information of the silicon interface formation, ionic sub-implantation simulations were performed, by the software SRIM/TRIM. Raman spectroscopy was used to verify the atomic structure of the films. Scratch tribological test was performed to study adhesion. It was observed that the mechanical and tribological properties were greatly improved with the deposition of DLC films on the silicon interface. A correlation between the residual stress and adhesion of DLC films was found.
Authors: Jun Zhang, Bin He, Xin Li Wei, Zhen Wei Yuan
Abstract: The adhesion strength of Diamond-like carbon (DLC) deposited onto silicon substrates using an arc-pulse sputtering technique was studied by experiments and numerical simulations. A scratch test was used to detect the adhesion strength of the DLC coating, which was simplified by two processes of tearing and peeling for FEA. The numerical simulations were performed by ABAQUS to calculate the two processes and integrate the result. The FEM simulation results fit with the scratch test. It is concluded that the simulation method is effusive and can be adopted to calculate the adhesion strength of DLC coating on the silicon substrate structure in other cases.
Authors: Jun Zhang, Yang Li, Xin Li Wei
Abstract: Thermal expansion mismatch is the most important which leads to the film/substrate interface damage and destruction. In this paper, the interface stresses analyses was conducted using Airy functions for the diamond-like carbon (DLC) film/ tungsten cobalt alloy(WC-Co) substrate structure; according to stress-strain relation, obtain the interface stress expression by substituting into the boundary conditions for giving parameter. The calculation results were analyzed and compared with the FEM simulation.
Authors: Jium Fang, Maw Tyan Sheen, Ming Der Jean
Abstract: A new approach with adaptive network-based fuzzy inference systems (ANFIS) based on experimental designs was used to model and characterize the tribological behaviors of diamond-like carbon (DLC) films deposited by a magnetron sputtering system. An orthogonal array experiment was introduced and the effects of deposited parameters on the films were systematically explored. The films were analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In this study, a group of highly developed hillock-like textures appeared and a lower wear volume loss became visible in the DLC films. Furthermore, the predicted values and experimental results, in which the ANFIS effectively predicts the tribological behaviors of the DLC films, are similar. It was experimentally confirmed the ANFIS predictions agreed with the experiments. Therefore, the experimental results demonstrate the tribological properties on DLC multilayer films are accurately predicted by ANFIS, thereby justifying the reliability and feasibility of the approach.
Authors: Yu Sen Yang, Wesley Huang, Ming Shyan Huang, Cheng Fong Huang
Abstract: Sticking problems in injection molds are a significant challenge in product quality control. Molds are usually coated with a surface ceramic layer to prevent sticking problems. This study presents two films deposited on light-guide plate microinjection molds using an unbalanced magnetron sputtering process to investigate the anti-sticking property of molds. The deposited film materials include chromium nitride (Cr-N) and zirconium containing diamond-like carbon (Zr-DLC). The anti-stick film properties examined here include water contact angles, the coefficients of friction, as well as product flatness for the practical injection process. The results show that the performance of Cr-N films involve water contact angles at 111.4 degrees and a coefficient of friction at 0.742, respectively. The performances of Zr-DLC films involve water contact angles at 86.2 degrees and a coefficient of friction at 0.106, respectively. For the practical injection process, the deposited Cr-N films have better anti-sticking property than do the deposited Zr-DLC films.
Authors: S. Kobayashi, Y. Ohgoe, K. Ozeki, Li Gei, K.K. Hirakuri, Hideyuki Aoki
Abstract: A variety of dental devices such as orthodontics, artificial teeth are implanted in oral cavity for long term. The implant coated with protective films, which can reduce corrosion and wear, may prevent the problems described above and extend the lifetime of implants to the benefit of the patients. Diamond-like carbon films have extreme hardness, low friction coefficients, chemical inertness, and high-corrosion resistance. Moreover, these properties make the good candidates as biocompatible coatings for dental devices. In this study, DLC films using the plasma CVD method deposited on acrylic resin and orthodontic archwires have investigated to detect the Ni release from the wires and to estimate cell growth in E-MEM immersed acrylic plates. After 6 months, the concentration of the nickel release from DLC-coated wire and Non-coated wire was 150 [ppb] and 933 [ppb], respectively. Results indicated DLC films inhibit the release of these materials, and prevent degradation of these materials in the solution.
Authors: E.T. Uzumaki, C.S. Lambert, W.D. Belangero, Cecília A.C. Zavaglia
Abstract: A great number of studies have shown that diamond-like carbon (DLC) coatings could be developed for orthopaedic implants, but few articles have been published about in vivo evaluation. In this study, DLC coatings were deposited on titanium alloy (Ti-13Nb-13Zr) implants using the plasma immersion implantation and deposition (PIII-D), and the in vivo biocompatibility of DLC coatings was evaluated into both muscular tissue and femoral condyles of rats. Results indicate that DLC coatings are biocompatible in vivo, and DLC-coated implants were observed directly bonding to bone without any intervening soft tissue layer.
Authors: Dong Cai Zhao, Geng Jie Xiao, Zhan Ji Ma, Sheng Hu Wu
Abstract: A series of diamond-like carbon (DLC) films with different Si concentration were prepared by changing the ratio of the number of Si-doped graphite target and pure graphite target. As the Si concentration in the thin film keep on increasing, the concentration of C-Si bond will increase leading to decrease of hardness and stress and increase of friction coefficient. In order to synthesize DLC films on metal substrates 3 types of interlayer have been made. The first and second interlayer is made up Ti/TiCx, and the second is thicker, the third interlayer is made up Ti/TiNx/TiNxCy, with the same thickness of the second. We also prepared DLC films with 6.7 at.% Si concentration on TC4 and Cr12 substrates with the third interlayer, and the thickness, hardness and fiction coefficients is about 0.652m, 4200Hv and 0.15, respectively. The adhesion of films had been greatly strengthened with a proper interlayer, and the value is more than 39N/mm2
Authors: Chi Lung Chang, Jui Yun Jao, Wei Yu Ho, Da Yung Wang
Abstract: The combinations of TiAl-doped DLC and TiAlN/TiN layers were designed to deposit on the tool steels using cathodic arc evaporation in a continuously single batch process. The economic advantage in depositing the combined coating in one production scale of PVD system is of practical importance. The TiAl-doped DLC as lubricant coatings were synthesized by using arc plasma sources mounted with Ti50Al50-target to emit high energy ion plasma to activate the decomposition of acetylene reactive gases. The results show that the TiAl-doped DLC and TiAlN/TiN combined coatings retained lower friction coefficient at approximately 0.15 during the steady-state sliding. The lubricity and wear resistance of TiAl-doped DLC/TiAlN/TiN coatings is then demonstrated to potentially be applied to the cutting tools with no lubricants.
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