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Diamond-like Carbon (diamond-like + carbon)
Selected AbstractsDiamond-like carbon coated polymer-based targets in microscope slide format for MALDI mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 5 2010Wolfgang Winkler First page of article [source] Tribochemistry of tetrahedral hydrogen-free amorphous carbon coatings in the presence of OH-containing lubricantsLUBRICATION SCIENCE, Issue 2 2008C. Matta Abstract Diamond-like carbon (DLC) films are gaining attention for its use in a wide range of tribological applications because of their low friction coefficient and high wear resistance. Recently, ultra-low friction or superlubricity as low as 0.006 has been observed between hydrogen-free DLC films lubricated with oil containing a glycerol mono-oleate (GMO) additive. Consequently, there are many efforts to understand their detailed tribological behaviour. In this study, first, a characterisation of a pristine hydrogen-free tetrahedral amorphous DLC coating (denoted as ta-C) is presented. The technique used for ta-C characterisation is the energy-filtered transmission electron microscopy studied on a focus ion beam cross section of the coating. Then, to simulate the action of GMO, which is used as an additive in engine oils, and to understand its mechanism of action in boundary lubrication conditions, simple and shorter molecules such as pure glycerol and hydrogen peroxide are used in friction tests. These two molecules and GMO have the same alcohol chemical function. Friction tests in the presence of pure glycerol and hydrogen peroxide are presented. Moreover, to understand the properties of these two molecules, the overtone of GMO and their reaction mechanism in boundary lubrication, liquid phase lubrication was simulated by gas phase lubrication. Results show that very low friction coefficients are obtained with no apparent wear. Finally, the mechanisms of ultra-low friction are investigated by the wetting method and the X-ray photoelectron spectroscopy (XPS) technique. These two techniques are used to identify the physical (wetting method) and chemical (XPS) changes occurring at the ta-C surface after friction. Copyright © 2007 John Wiley & Sons, Ltd. [source] Microstructure of diamond-like carbon films prepared using acetylene and toluene by bipolar-type plasma based ion implantationPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2008S. Nakao Abstract Diamond-like carbon (DLC) films are deposited on Si substrates using acetylene (C2H2), toluene (C7H8) and their mixed gas, and the microstructures are examined by micro-Raman spectroscopy, Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD) analysis as a function of negatively pulsed voltages (Vn). It is found that the formation of graphite-like structure (aromatic ring clustering) is enhanced with increasing Vn. In addition, the density of the films is increased up to approximately 2.0 g/cm3 and the H concentration is decreased with increasing Vn. The use of C2H2 has much effect on the formation of graphite-like structure and the reduction of H concentration in the films at high Vn as compared with others. The deposition rate of the films is increased with increasing Vn. Relatively high deposition rate is obtained when using C7H8. In the case of the mixed gas, the deposition rate is found to be close to that of C7H8. These results suggest that C7H8 is dominant to the deposition process when using the mixture of C2H2 + C7H8. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Evaluation of Adhesion and Wear Resistance of DLC Films Deposited by Various MethodsPLASMA PROCESSES AND POLYMERS, Issue 6-7 2009Takahiro Horiuchi Abstract Diamond-like carbon (DLC) coatings are currently being used in a wide variety of industrial fields because of their outstanding properties, such as high hardness and low friction coefficient, among others. DLC coatings have various characteristics depending on the deposition method used. However, they have a problem regarding adhesion with the base material, which is a major factor hindering their expanded application in other fields. The adhesion of DLC coatings is generally evaluated using Rockwell indentation tests and scratch tests. These test methods induce damage in the specimen with the application of a single load. Accordingly, there is a problem of low correlation between such test results and evaluations of the adhesion of coatings on actual components that undergo repeated sliding cycles. With the aim of resolving that problem, this study evaluated the damage condition of three types of DLC coatings having different physical properties using newly devised cyclic sliding test methods involving the application of a continuously increasing load. The evaluation results obtained with these new methods differed from the results of Rockwell tests and scratch tests. These new test methods are more able to reproduce the damage done to DLC coatings in actual sliding cycles. This paper describes the test procedures and the evaluation results obtained. [source] Raman spectroscopic and X-ray investigation of stressed states in diamond-like carbon filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1-2 2005R. Krawietz Abstract The non-destructive characterization of intrinsic stress is very important to evaluate the reliability of devices based on diamond-like carbon (DLC) films. Whereas the only requirement for the X-ray diffraction method is a crystalline state of specimen, Raman spectroscopic stress analysis is restricted to materials showing intensive and sharp Raman peaks. On the other hand, Raman spectroscopy offers the possibility to measure stress profiles with lateral resolution of about 1 micron. The results of stress measurements in DLC films using both X-ray diffraction and Raman spectroscopy are found in very good correspondence. Mean stress in carbon films consisting of very small crystallites on silicon substrates has been determined by measuring and fitting the stress profiles in the substrate near artificial vertical film edges. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Bacterial adhesion to diamond-like carbon as compared to stainless steelJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Antti Soininen Abstract Recent studies suggest that diamond-like carbon (DLC) coatings are suitable candidates for application on biomedical devices and implants, due to their high hardness, low friction, high wear and corrosion resistance, chemical inertness, smoothness, and tissue and blood compatibility. However, most studies have neglected the potential susceptibility of DLC coatings to bacterial adhesion, which is the first step in the development of implant-related infections. This study compares adhesion of seven bacterial strains, commonly implicated in implant-related infections, to tetrahedral amorphous carbon, with their adhesion to AISI 316L surgical steel. The results show that bacterial adhesion to DLC was similar to the adhesion to commonly used stainless steel. This suggests that DLC coating can be advantageously used on implants made of AISI 316L or other materials without increasing the risk to implant-related infections. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Tribological interactions between DLC coatings and lubricantsLUBRICATION SCIENCE, Issue 2 2008B. Podgornik Abstract In the last couple of years a tremendous research work has been done in the field of development and characterization of hard coatings, mainly to boost their use in machine component applications working under normal and extreme operating conditions. Generally, hard coatings improve tribological properties of contact surfaces under dry sliding, while under lubricated conditions their inertness hinder the possibility of boundary film formation. The aim of this paper is to elaborate on the interactions between diamond-like carbon (DLC) coatings and lubricants, and possible tribofilm formation in different tribological contacts. Therefore, relationships between surface properties (i.e. surface tension, surface free energy, contact angle) and tribological properties of the lubricated DLC coated contact, as well as the influence of oil additive type and concentration and contact conditions will be presented. It is believed that this type of knowledge will lead to further coatings modification in terms of improved tribological properties under boundary lubrication. Copyright © 2007 John Wiley & Sons, Ltd. [source] Microtribological behaviour of thin DLC films using different testing methodsLUBRICATION SCIENCE, Issue 2 2006R. Bandorf Abstract To enhance the lifetime and reliability of microcomponents, thin microtribological films are applied to microparts. With reduction of the component size, investigation methods for tribological testing must be adapted. This paper studies the microtribological behaviour of thin diamond-like carbon (DLC) films using different testing methods. To tie in with macroscopic results, to determine friction we used the well-known pin-on-disc test with spherical surfaces of 10,mm diameter under a typical load of 3,N. For investigations of the behaviour under single asperity contact, Atomic Force Microscope (AFM) methods with applied loads of a few hundred micronewtons were used. Investigations on thin DLC films showed that the friction coefficient under single asperity contact is strongly dependent on the applied load and the resulting contact area. Especially for thin films (up to a few hundred nanometres) the friction coefficient is influenced by the substrate material. With decreasing substrate Young's modulus the friction coefficient also decreases. On the other hand, an increase in the abrasive wear resistance was observed using soft substrate materials. In this paper we show that the friction coefficient was also reduced by a simple surface structure. For investigations we used photolithography to create concentric circles in different substrates. This resulted in a behaviour like riding on rails for the pin-on-disc test. Depending on the tribological pairing the friction coefficient was reduced to more than 50% of the original value. Copyright © 2006 John Wiley & Sons, Ltd. [source] Tribological characterisation of hard coatings with and without DLC top layer in fretting testsLUBRICATION SCIENCE, Issue 1 2006D. KlaffkeArticle first published online: 14 DEC 200 Abstract The potential of coatings to protect components against wear and to reduce friction has led to a large variety of protective coatings. In order to check the success of coating modifications and to find solutions for different purposes, initial tests with laboratory tribometers are usually done to give information about the performance of a coating. Different Ti-based coatings (TiN, Ti(C,N), and TiAlN) and NiP were tested in comparison to coatings with an additional diamond-like carbon (DLC) top coating. Tests were done in laboratory air at room temperature with oscillating sliding (gross slip fretting) with a ball-on-disc arrangement against a ceramic ball (Al2O3). Special attention was paid to possible effects of moisture (relative humidity). The coefficient of friction was measured on line, and the volumetric wear at the disc was determined after the test from microscopic measurements of the wear scar and additional profiles. The friction and wear behaviour is quite different for the different coatings and depends more or less on the relative humidity. The DLC coating on top of the other coatings reduces friction and wear considerably. In normal and in moist air the coefficient of wear of the DLC top-layer coating is significantly less than 10,6,mm3/Nm and the coefficient of friction is below 0.1. In dry air, however, there is a certain tendency to high wear and high friction. Copyright © 2006 John Wiley & Sons, Ltd. [source] Abrasive Wear of DLC/PVD Multilayer Coatings: AFM StudiesLUBRICATION SCIENCE, Issue 3 2004C. Martini Abstract The tribological behaviour of multilayered coatings deposited on plain carbon steel was investigated by microscale abrasion tests (MSATs). The multilayered coatings consisted of an outer diamond-like carbon (DLC) layer, a physical vapour deposition (PVD) nitride-based interlayer, and an inner electroless Ni-P layer. PVD TiN- and Ti(C,N)-coated samples with and without the DLC outer layer were studied in order to evaluate the influence of each layer on the tribological behaviour of the multilayer-coated system. The MSATs were carried out using a device based on ball-cratering geometry: a hard steel sphere was rotated against the coated specimen in the presence of an aqueous suspension of SiC particles. The wear coefficients of the multilayers were calculated from the diameter of the wear craters. The morphology of the wear scars produced by the MSATs was studied by atomic force microscopy (AFM). The wear damage was described by measuring the r.m.s. roughness (Sq) on the sides of the wear craters. Roughness values were related to the wear coefficients (kc) for the different multilayers on the basis of mathematical elaboration typical of the ,design of experiment' (DOE) statistical technique. The presence of the DLC outer layer reduced the roughness of the crater sides and significantly increased the wear resistance of the multilayer only in the case of the PVD TiN sublayer. [source] Position-sensitive radiation detectors made of single crystal CVD diamondPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 9 2009M. Pomorski Abstract Based on a single crystal chemical vapour deposition (scCVD) diamond plate a position sensitive detector [position sensitive detection position sensitive detector (PSD)] has been fabricated. The ,9,mm2 sensing area of the detector consists of a diamond-like carbon (DLC) thin film, in the form of a plane-pad resistive electrode layer deposited on the scCVD surface. The 1D position information is obtained from the resistive charge division between two collecting electrodes located at the extremities of the DLC sensing electrode. The detector properties have been tested using a 241Am ,-particles source. The timing characteristics of the device were probed using broad-band (BB) electronics: the signal formation does not exceed 30,ns, thus detector operation with a negligible ballistic effect is possible at high rates approaching 107,particles/s. The linearity and position resolution of the device was measured using low-noise charge-sensitive (CS) electronics: the position resolution reaches 30,µm (,), the deviation from linearity remain below 2% in the full range of the detector sensing area. [source] Optical effect of diamond-like carbon film coating of long-period optical fiber gratingsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2007M. Smietana Abstract The paper presents diamond-like carbon (DLC) film as a coating for long-period grating (LPG) optical fiber structure. The spectral response of a DLC-coated LPG structure is strictly dependent on Radio Frequency Plasma Chemical Vapour Deposition (RF PCVD) process parameters. The paper discusses the influence of DLC deposition time and self-bias voltage to shift of the LPG resonance peak and explores the possibility of using the structure as a refractometric sensor. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Nanosized Diamond Deposition via Plasma MediumPLASMA PROCESSES AND POLYMERS, Issue S1 2007Babak Shokri Abstract An arc jet plasma technique is used to produce nanosized diamond particle deposition and for the deposition of diamond-like carbon at high growth rates. In this case, atomic hydrogen produced in the arc plasma participates in the methane decomposition. In addition, a thermodynamic modeling will be presented for the nucleation of stable diamond as nanoparticles and thin films and the computation was made in the range of the applied plasma reactor. [source] VmeCN Based Nanoscale Multilayer PVD Coatings Deposited by the Combined High Power Impulse Magnetron Sputtering/Unbalanced Magnetron Sputtering TechnologyPLASMA PROCESSES AND POLYMERS, Issue S1 2007Papken Eh. Abstract TiAlCN/VCN has been deposited by the combined high power impulse magnetron sputtering/unbalanced magnetron sputtering (HIPIMS/UBM) technology using a Hauzer HTC 1000-4 PVD system. V+ ion flux has been generated by HIPIMS discharge to sputter-clean the substrates prior to the coating deposition. The sputtering was carried out in a mixed CH4, N2 and Ar atmosphere. Coatings phase and nanoscale structure were characterised using a variety of surface analysis techniques. In dry milling of Al 7010-T 7651 alloy, a TiAlCN/VCN nanoscale multilayer PVD coating outperformed state-of-the-art diamond-like carbon (DLC, Cr/WC/a-CH) coating by a factor of four. In drilling Al-alloy enforced MMC materials, cemented carbide drills coated with TiAlCN/VCN produced 130 holes compared to one to two holes with uncoated drills. [source] | |||||||||||||