WorldWideScience

Sample records for adherent diamond-like carbon

  1. XPS, XRD and laser raman analysis of surface modified of 6150 steel substrates for the deposition of thick and adherent diamond-like carbon coatings

    OpenAIRE

    William de Melo Silva; José Rubens Gonçalves Carneiro; Vladimir Jesus Trava-Airoldi

    2013-01-01

    Although the 6150 steel has an excellent fatigue and impact resistance, it is unsuitable to operate it when the corrosion is a limited factor. We propose here a sequence of steel pre-treatment by carburizing, carbonitriding and nitriding in order to improve the poor adhesion between Diamond Like-Carbon coatings on steel. This sequence is our attempt to reduce the difference between the coefficients of thermal expansion of steel and DLC through the graded interface. This work demonstrates the ...

  2. Graphene diamond-like carbon films heterostructure

    Science.gov (United States)

    Zhao, Fang; Afandi, Abdulkareem; Jackman, Richard B.

    2015-03-01

    A limitation to the potential use of graphene as an electronic material is the lack of control over the 2D materials properties once it is deposited on a supporting substrate. Here, the use of Diamond-like Carbon (DLC) interlayers between the substrate and the graphene is shown to offer the prospect of overcoming this problem. The DLC films used here, more properly known as a-C:H with ˜25% hydrogen content, have been terminated with N or F moieties prior to graphene deposition. It is found that nitrogen terminations lead to an optical band gap shrinkage in the DLC, whilst fluorine groups reduce the DLC's surface energy. CVD monolayer graphene subsequently transferred to DLC, N terminated DLC, and F terminated DLC has then been studied with AFM, Raman and XPS analysis, and correlated with Hall effect measurements that give an insight into the heterostructures electrical properties. The results show that different terminations strongly affect the electronic properties of the graphene heterostructures. G-F-DLC samples were p-type and displayed considerably higher mobility than the other heterostructures, whilst G-N-DLC samples supported higher carrier densities, being almost metallic in character. Since it would be possible to locally pattern the distribution of these differing surface terminations, this work offers the prospect for 2D lateral control of the electronic properties of graphene layers for device applications.

  3. Graphene diamond-like carbon films heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Fang; Afandi, Abdulkareem; Jackman, Richard B., E-mail: r.jackman@ucl.ac.uk [London Centre for Nanotechnology, Electronic and Electrical Engineering Department, University College London, 17-19 Gordon Street, London WC1H 0AH (United Kingdom)

    2015-03-09

    A limitation to the potential use of graphene as an electronic material is the lack of control over the 2D materials properties once it is deposited on a supporting substrate. Here, the use of Diamond-like Carbon (DLC) interlayers between the substrate and the graphene is shown to offer the prospect of overcoming this problem. The DLC films used here, more properly known as a-C:H with ∼25% hydrogen content, have been terminated with N or F moieties prior to graphene deposition. It is found that nitrogen terminations lead to an optical band gap shrinkage in the DLC, whilst fluorine groups reduce the DLC's surface energy. CVD monolayer graphene subsequently transferred to DLC, N terminated DLC, and F terminated DLC has then been studied with AFM, Raman and XPS analysis, and correlated with Hall effect measurements that give an insight into the heterostructures electrical properties. The results show that different terminations strongly affect the electronic properties of the graphene heterostructures. G-F-DLC samples were p-type and displayed considerably higher mobility than the other heterostructures, whilst G-N-DLC samples supported higher carrier densities, being almost metallic in character. Since it would be possible to locally pattern the distribution of these differing surface terminations, this work offers the prospect for 2D lateral control of the electronic properties of graphene layers for device applications.

  4. Graphene diamond-like carbon films heterostructure

    International Nuclear Information System (INIS)

    A limitation to the potential use of graphene as an electronic material is the lack of control over the 2D materials properties once it is deposited on a supporting substrate. Here, the use of Diamond-like Carbon (DLC) interlayers between the substrate and the graphene is shown to offer the prospect of overcoming this problem. The DLC films used here, more properly known as a-C:H with ∼25% hydrogen content, have been terminated with N or F moieties prior to graphene deposition. It is found that nitrogen terminations lead to an optical band gap shrinkage in the DLC, whilst fluorine groups reduce the DLC's surface energy. CVD monolayer graphene subsequently transferred to DLC, N terminated DLC, and F terminated DLC has then been studied with AFM, Raman and XPS analysis, and correlated with Hall effect measurements that give an insight into the heterostructures electrical properties. The results show that different terminations strongly affect the electronic properties of the graphene heterostructures. G-F-DLC samples were p-type and displayed considerably higher mobility than the other heterostructures, whilst G-N-DLC samples supported higher carrier densities, being almost metallic in character. Since it would be possible to locally pattern the distribution of these differing surface terminations, this work offers the prospect for 2D lateral control of the electronic properties of graphene layers for device applications

  5. XPS, XRD and laser raman analysis of surface modified of 6150 steel substrates for the deposition of thick and adherent diamond-like carbon coatings

    Directory of Open Access Journals (Sweden)

    William de Melo Silva

    2013-06-01

    Full Text Available Although the 6150 steel has an excellent fatigue and impact resistance, it is unsuitable to operate it when the corrosion is a limited factor. We propose here a sequence of steel pre-treatment by carburizing, carbonitriding and nitriding in order to improve the poor adhesion between Diamond Like-Carbon coatings on steel. This sequence is our attempt to reduce the difference between the coefficients of thermal expansion of steel and DLC through the graded interface. This work demonstrates the quantitative analysis of the molecules present at surface using X-ray photoelectron spectroscopy. The crystallographic structures are investigated by X-ray diffraction which shows the formation of carbides and nitride phases. Raman spectroscopy reveals the carburizing surface characteristics where DLC coating is nucleated and grown at the substrate. At the end of the analysis it is possible to verify which molecules and phases are formed on the steel surface interface after each step of pre-treatment.

  6. XPS, XRD and laser Raman analysis of surface modified of 6150 steel substrates for the deposition of thick and adherent diamond-like carbon coatings

    Energy Technology Data Exchange (ETDEWEB)

    Silva, William de Melo; Carneiro, Jose Rubens Goncalves, E-mail: williammelosilva@gmail.com [Pontificia Universidade Catolica de Minas Gerais (PUC-MG), Belo Horizonte (Brazil). Dept. de Engenharia Mecanica; Trava-Airoldi, Vladimir Jesus [Associate Laboratory of Sensors and Materials, National Institute for Space Research, Sao Jose dos Campos, SP (Brazil)

    2013-11-01

    Although the 6150 steel has an excellent fatigue and impact resistance, it is unsuitable to operate it when the corrosion is a limited factor. We propose here a sequence of steel pre-treatment by carburizing, carbonitriding and nitriding in order to improve the poor adhesion between Diamond Like-Carbon coatings on steel. This sequence is our attempt to reduce the difference between the coefficients of thermal expansion of steel and DLC through the graded interface. This work demonstrates the quantitative analysis of the molecules present at surface using X-ray photoelectron spectroscopy. The crystallographic structures are investigated by X-ray diffraction which shows the formation of carbides and nitride phases. Raman spectroscopy reveals the carburizing surface characteristics where DLC coating is nucleated and grown at the substrate. At the end of the analysis it is possible to verify which molecules and phases are formed on the steel surface interface after each step of pre-treatment. (author)

  7. Diamond-like carbon coated ultracold neutron guides

    Energy Technology Data Exchange (ETDEWEB)

    Heule, S. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland) and Physik-Institut der Universitaet Zuerich (Switzerland)]. E-mail: stefan.heule@psi.ch; Atchison, F. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Daum, M. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Foelske, A. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Henneck, R. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Kasprzak, M. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Stefan Meyer Institut fuer subatomare Physik, Austrian Academy of Sciences, Vienna (Austria); Kirch, K. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Knecht, A. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Physik-Institut der Universitaet Zuerich (Switzerland); Kuzniak, M. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Jagellonian University, Cracow (Poland); Lippert, T. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Meier, M. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Pichlmaier, A. [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Straumann, U. [Physik-Institut der Universitaet Zuerich (Switzerland)

    2007-07-31

    It has been shown recently that diamond-like carbon (DLC) with a sp{sup 3} fraction above 60% is a better wall coating material for ultracold neutron applications than beryllium. We report on results of Raman spectroscopic and XPS measurements obtained for diamond-like carbon coated neutron guides produced in a new facility, which is based on pulsed laser deposition at 193 nm. For diamond-like carbon coatings on small stainless steel substrates we find sp{sup 3} fractions in the range from 60 to 70% and showing slightly increasing values with laser pulse energy and pulse repetition rate.

  8. Raman spectra of electrochemically hydrogenated diamond like carbon surface

    OpenAIRE

    Biswas, Hari Shankar; Datta, Jagannath; Sen, Pintu; Ghosh, Uday Chand; Ray, Nihar Ranjan

    2013-01-01

    Raman spectroscopy has been employed to distinguish between the Raman spectrum of pristine hydrogenated diamond like carbon (PHDLC) and that of electrochemically hydrogenated diamond like carbon (ECHDLC). The enhancement of the background photoluminescence (PL) in the Raman spectrum and broadening of PL spectrum of ECHDLC are identified to be due to increase of sp3 C-H density onto the PHDLC surface, during novel electrochemical process of hydrogenation of sp2 C=C into sp3 C-H.

  9. Optically transparent, scratch-resistant, diamond-like carbon coatings

    Science.gov (United States)

    He, Xiao-Ming; Lee, Deok-Hyung; Nastasi, Michael A.; Walter, Kevin C.; Tuszewski, Michel G.

    2003-06-03

    A plasma-based method for the deposition of diamond-like carbon (DLC) coatings is described. The process uses a radio-frequency inductively coupled discharge to generate a plasma at relatively low gas pressures. The deposition process is environmentally friendly and scaleable to large areas, and components that have geometrically complicated surfaces can be processed. The method has been used to deposit adherent 100-400 nm thick DLC coatings on metals, glass, and polymers. These coatings are between three and four times harder than steel and are therefore scratch resistant, and transparent to visible light. Boron and silicon doping of the DLC coatings have produced coatings having improved optical properties and lower coating stress levels, but with slightly lower hardness.

  10. Cell attachment on diamond-like carbon coating

    Indian Academy of Sciences (India)

    D J Li; H Q Gu

    2002-02-01

    Preliminary results of diamond-like carbon (DLC) coating with its novel properties with no toxicity have caused a strong interest of commercial manufacturers of surgical implants. DLC coatings were prepared on polymethylmethacrylate (PMMA) at room temperature using ion beam assisted deposition (IBAD). It could be shown by X-ray photoelectron spectroscopy, Auger electron spectroscopy, and Raman spectroscopy that DLC coating prepared by 800 eV CH+ beam bombardment possessed a higher fraction of 3 bonds in the structure of mixed 3 + 2 bonding, resulting in a higher hydrophobicity. The results of the cell attachment tests indicated that DLC coatings exhibited low macrophage attachment and provided desirable surface for the normal cellular growth and morphology of the fibroblasts. At the same time, the number of both neutral granulocytes and platelets adhering to DLC coatings decreased significantly. These findings showed that DLC was a better coating with desirable tissue and blood compatibility.

  11. Diamond-like carbon for data and beer storage

    Directory of Open Access Journals (Sweden)

    Cinzia Casiraghi

    2007-01-01

    Full Text Available Carbon is a very versatile element that can crystallize in the forms of diamond or graphite. There are many noncrystalline carbons, known as amorphous carbons. An amorphous carbon with a high fraction of diamond-like (sp3 bonds is named diamond-like carbon (DLC. Unlike diamond, DLC can be deposited at room temperature. Furthermore, its properties can be tuned by changing the sp3 content, the organization of the sp2 sites, and the hydrogen content. This makes DLC ideal for a variety of different applications. We review the use of ultrathin DLC films for ultrahigh-density data storage in magnetic and optical disks and ultralong beer storage in plastic bottles.

  12. Preparation and Thermal Characterization of Diamond-Like Carbon Films

    Institute of Scientific and Technical Information of China (English)

    BAI Su-Yuan; TANG Zhen-An; HUANG Zheng-Xing; Yu Jun; WANG Jing; LIU Gui-Chang

    2009-01-01

    Diamond-like carbon (DLC) films are prepared on silicon substrates by microwave electron cyclotron resonance plasma enhanced chemical vapor deposition. Raman spectroscopy indicates that the films have an amorphous structure and typical characteristics. The topographies of the films are presented by AFM images. Effective thermal conductivities of the films are measured using a nanosecond pulsed photothermal reflectance method. The results show that thermal conductivity is dominated by the microstructure of the films.

  13. Properties of nitrogen containing diamond-like carbon films

    International Nuclear Information System (INIS)

    Optical and mechanical properties of nitrogen containing diamond- like carbon (NC-DLC) films deposited by RF plasma decomposition of CH4:H2:N2 gas mixture were investigated. Nitrogen was incorporated into DLC films both during film growth and after deposition of film by implantation of nitrogen ions. It was shown that both optical and mechanical properties of the films strongly depend on nitrogen content in the films. In some cases the mechanical properties of nitrogen implanted films were improved in comparison with unimplanted samples. (author). 7 refs., 2 figs

  14. Tribocorrosion of Diamond Like Carbon (DLC) coatings for biomedical applications

    OpenAIRE

    Sanchez Adam, Jorge

    2015-01-01

    Tribocorrosion has arisen as one of the most important material degradation processes in biomedical applications; thus, the improvement of the materials used in hip or knee prosthesis is very relevant. The aim of this project is to test the outstanding properties of the diamond like carbon material as a coating; a comparison between CoCrMo with several types of DLC as ta-C, a-C:H and metal doped with Ti and Si. Also different deposition methods will be compared like Physical Vapour Deposit...

  15. Method and apparatus for making diamond-like carbon films

    Science.gov (United States)

    Pern, Fu-Jann; Touryan, Kenell J.; Panosyan, Zhozef Retevos; Gippius, Aleksey Alekseyevich

    2008-12-02

    Ion-assisted plasma enhanced deposition of diamond-like carbon (DLC) films on the surface of photovoltaic solar cells is accomplished with a method and apparatus for controlling ion energy. The quality of DLC layers is fine-tuned by a properly biased system of special electrodes and by exact control of the feed gas mixture compositions. Uniform (with degree of non-uniformity of optical parameters less than 5%) large area (more than 110 cm.sup.2) DLC films with optical parameters varied within the given range and with stability against harmful effects of the environment are achieved.

  16. Plasma Processes : Microwave plasma deposition of diamond like carbon coatings

    Indian Academy of Sciences (India)

    D S Patil; K Ramachandran; N Venkatramani; M Pandey; R D'Cunha

    2000-11-01

    The promising applications of the microwave plasmas have been appearing in the fields of chemical processes and semiconductor manufacturing. Applications include surface deposition of all types including diamond/diamond like carbon (DLC) coatings, etching of semiconductors, promotion of organic reactions, etching of polymers to improve bonding of the other materials etc. With a 2.45 GHz, 700 W, microwave induced plasma chemical vapor deposition (CVD) system set up in our laboratory we have deposited diamond like carbon coatings. The microwave plasma generation was effected using a wave guide single mode applicator. We have deposited DLC coatings on the substrates like stainless steel, Cu–Be, Cu and Si. The deposited coatings have been characterized by FTIR, Raman spectroscopy and ellipsometric techniques. The results show that we have achieved depositing ∼ 95% sp3 bonded carbon in the films. The films are uniform with golden yellow color. The films are found to be excellent insulators. The ellipsometric measurements of optical constant on silicon substrates indicate that the films are transparent above 900 nm.

  17. Advances in targetry with thin diamond-like carbon foils

    CERN Document Server

    Liechtenstein, V K; Olshanski, E D; Repnow, R; Levin, J; Hellborg, R; Persson, P; Schenkel, T

    2002-01-01

    Thin and stable diamond-like carbon (DLC) foils, which were fabricated at the Kurchatov Institute by sputter deposition, have proved recently to be advantageous for stripping and secondary electron timing of high energy heavy ions in a number of accelerator experiments. This resulted in expanding applications of these DLC foils which necessitated further development efforts directed toward the following applications of DLC targetry: (i) thin stripper foils for lower energy tandem accelerators, (ii) enlarged (up to 66 mm in diameter) stop foils for improved time-of-flight elastic recoil detection ion beam analysis, and (iii) ultra-thin (about 0.6 mu g/cm sup 2) DLC foils for some fundamental and applied physics experiments. Along with the fabrication of thin DLC stripper foils for tandem accelerators, much thicker (up to 200 mu g/cm sup 2) foils for post-stripping of heavy-ion beams in higher energy linacs, are within reach.

  18. Development of Diamond-like Carbon Fibre Wheel

    Institute of Scientific and Technical Information of China (English)

    魏源迁; 山口勝美; 洞口巌; 竹内雅之

    2004-01-01

    A unique diamond-like carbon (DLC) grinding wheel was developed, in which the DLC fibres were made by rolling Al sheets coated with DLC films and aligned normally to the grinding wheel surface by laminating Al sheets together with DLC fibres. In this paper, the formation process of DLC fibres and the fabrication process of a DLC fibre wheel were investigated. Many grinding experiments were also carried out on a precision NC plane milling machine using a newly developed DLC wheel. Grinding of specimens of silicon wafers, optical glasses, quartz, granites and hardened die steel SKD11 demonstrated the capabilities of nanometer surface finish. A smooth surface with a roughness value of Ra2.5nm (Ry26nm) was achieved.

  19. Atmospheric Plasma Deposition of Diamond-like Carbon Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ladwig, Angela

    2008-01-23

    There is great demand for thin functional coatings in the semiconductor, optics, electronics, medical, automotive and aerospace industries [1-13]. As fabricated components become smaller and more complex, the properties of the materials’ surface take on greater importance. Thin coatings play a key role in tailoring surfaces to give them the desired hardness, wear resistance, chemical inertness, and electrical characteristics. Diamond-like carbon (DLC) coatings possess an array of desirable properties, including outstanding abrasion and wear resistance, chemical inertness, hardness, a low coefficient of friction and exceptionally high dielectric strength [14-22]. Diamond-like carbon is considered to be an amorphous material, containing a mixture of sp2 and sp3 bonded carbon. Based on the percentage of sp3 carbon and the hydrogen content, four different types of DLC coatings have been identified: tetrahedral carbon (ta-C), hydrogenated amorphous carbon (a-C:H) hard, a-C:H soft, and hydrogenated tetrahedral carbon (ta-C:H) [20,24,25]. Possessing the highest hardness of 80 GPa, ta-C possesses an sp3 carbon content of 80 to 88u%, and no appreciable hydrogen content whereas a-C:H soft possesses a hardness of less than 10 GPa, contains an sp3 carbon content of 60% and a hydrogen content between 30 to 50%. Methods used to deposit DLC coatings include ion beam deposition, cathodic arc spray, pulsed laser ablation, argon ion sputtering, and plasma-enhanced chemical vapor deposition [73-83]. Researchers contend that several advantages exist when depositing DLC coatings in a low-pressure environment. For example, ion beam processes are widely utilized since the ion bombardment is thought to promote denser sp3-bonded carbon networks. Other processes, such as sputtering, are better suited for coating large parts [29,30,44]. However, the deposition of DLC in a vacuum system has several disadvantages, including high equipment cost and restrictions on the size and shape of

  20. Electronic Power System Application of Diamond-Like Carbon Films

    Science.gov (United States)

    Wu, Richard L. C.; Kosai, H.; Fries-Carr, S.; Weimer, J.; Freeman, M.; Schwarze, G. E.

    2003-01-01

    A prototype manufacturing technology for producing high volume efficiency and high energy density diamond-like carbon (DLC) capacitors has been developed. Unique dual ion-beam deposition and web-handling systems have been designed and constructed to deposit high quality DLC films simultaneously on both sides of capacitor grade aluminum foil and aluminum-coated polymer films. An optimized process, using inductively coupled RF ion sources, has been used to synthesize electrically robust DLC films. DLC films are amorphous and highly flexible, making them suitable for the production of wound capacitors. DLC capacitors are reliable and stable over a wide range of AC frequencies from 20 Hz to 1 MHz, and over a temperature range from .500 C to 3000 C. The compact DLC capacitors offer at least a 50% decrease in weight and volume and a greater than 50% increase in temperature handling capability over equal value capacitors built with existing technologies. The DLC capacitors will be suitable for high temperature, high voltage, pulsed power and filter applications.

  1. Biomedical applications of diamond-like carbon coatings: a review.

    Science.gov (United States)

    Roy, Ritwik Kumar; Lee, Kwang-Ryeol

    2007-10-01

    Owing to its superior tribological and mechanical properties with corrosion resistance, biocompatibility, and hemocompatibility, diamond-like carbon (DLC) has emerged as a promising material for biomedical applications. DLC films with various atomic bond structures and compositions are finding places in orthopedic, cardiovascular, and dental applications. Cells grew on to DLC coating without any cytotoxity and inflammation. DLC coatings in orthopedic applications reduced wear, corrosion, and debris formation. DLC coating also reduced thrombogenicity by minimizing the platelet adhesion and activation. However, some contradictory results (Airoldi et al., Am J Cardiol 2004;93:474-477, Taeger et al., Mat-wiss u Werkstofftech 2003;34:1094-1100) were also reported that no significant improvement was observed in the performance of DLC-coated stainless stent or DLC-coated femoral head. This controversy should be discussed based on the detailed information of the coating such as atomic bond structure, composition, and/or electronic structure. In addition, instability of the DLC coating caused by its high level of residual stress and poor adhesion in aqueous environment should be carefully considered. Further in vitro and in vivo studies are thus required to confirm its use for medical devices. PMID:17285609

  2. The irradiation studies on diamond-like carbon films

    CERN Document Server

    LiuGuIang; Xie Er Qin

    2002-01-01

    Diamond-like carbon (DLC) films have been deposited on glass substrates using radio-frequency (r.f.) plasma deposition method. gamma-ray, ultraviolet (UV) ray and neutron beam were used to irradiate the DLC films. Raman spectroscopy and infrared (IR) spectroscopy were used to characterize the changing characteristics of SP sup 3 C-H bond and hydrogen content in the films due to the irradiations. It showed that, the damage degrees of the gamma-ray, UV ray and neutron beam on the SP sup 3 C-H bonds are different. Among them, the damage of gamma-ray on the SP sup 3 C-H bond is the weakest. When the irradiation dose of gamma-ray reaches 10x10 sup 4 Gy, the SP sup 3 C-H bond reduces about 50% in number. The square resistance of the films is reduced due to the irradiation of UV ray and this is caused by severe oxidation of the films. Compared with that of the as-deposited one, the IR transmittance of the films irradiated by both gamma-ray and neutron beam is increased to some extent. By using the results on optical...

  3. Growth stress in tungsten carbide-diamond-like carbon coatings

    International Nuclear Information System (INIS)

    Growth stress in tungsten carbide-diamond-like carbon coatings, sputter deposited in a reactive argon/acetylene plasma, has been studied as a function of the acetylene partial pressure. Stress and microstructure have been investigated by wafer curvature and transmission electron microscopy (TEM) whereas composition and energy distribution functions of positive ions were obtained by electron probe microanalyzer, elastic recoil detection analysis, and mass-energy analyzer (MEA). It has been observed that the compressive stress decreases with increasing acetylene partial pressure, showing an abrupt change from -5.0 to -1.6 GPa at an acetylene partial pressure of 0.012 Pa. TEM micrographs show that by increasing the acetylene partial pressure in the plasma from 0 to 0.012 Pa, the microstructure of the coating changes from polycrystalline to amorphous. MEA results show that the most probable energy of positive ions bombarding the substrate during deposition in pure argon and argon/acetylene atmosphere is the same. Based on the results, it is concluded that the huge variation in the compressive stress at low acetylene partial pressures is due to a change in the microstructure of the coating from polycrystalline to amorphous and not to the energy of positive ions bombarding the film

  4. Friction of diamond-like carbon films in different atmospheres

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) films constitute a class of new materials with a wide range of compositions, properties, and performance. In particular, the tribological properties of these films are rather intriguing and can be strongly influenced by the test conditions and environment. In this paper, we performed a series of model experiments in high vacuum and with various added gases to elucidate the influence of different test environments on the tribological behavior of three DLC films. Specifically, we studied the behavior of a hydrogen-free film produced by a cathodic arc process and two highly hydrogenated films produced by plasma-enhanced chemical-vapor deposition. Flats and balls used in our experiments were coated with DLC and tested in a pin-on-disc machine under a load of 1 N and at constant rotational frequency. With a low background pressure, in the 10(sup -6) Pa range, the highly hydrogenated films exhibited a friction coefficient of less than 0.01, whereas the hydrogen-free film gave a friction coefficient of approximately 0.6. Adding oxygen or hydrogen to the experimental environment changed the friction to some extent. However, admission of water vapor into the test chamber caused large changes: the friction coefficient decreased drastically for the hydrogen-free DLC film whereas it increased a bit for one of the highly hydrogenated films. These results indicate that water molecules play a prominent role in the frictional behavior of DLC films-most notably for hydrogen-free films but also for highly hydrogenated films

  5. Diamond-like carbon/epoxy low-friction coatings to replace electroplated chromium

    OpenAIRE

    Podgoric, S; Jones, Benjamin; Bulpett, R; Troisi, G.; Franks, J

    2009-01-01

    A series of layered structures based on epoxy-resins coated with diamond-like carbon (DLC) are examined as potential replacements for electroplated chromium in aerospace applications. Diamond-like carbon coatings can offer superior mechanical properties and tribological performance; however, in some applications high internal stresses and poor adhesion limit their practical use. A DLC / epoxy system is developed and studied utilising pin-on-disk testing, analysis with scanning electron micr...

  6. Endovascular treatment of superficial femoral artery occlusive disease with stents coated with diamond-like carbon

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, O. E-mail: schaefer@mrs1.ukl.uni-freiburg.de; Lohrmann, C.; Winterer, J.; Kotter, E.; Langer, M

    2004-12-01

    A major consideration in the reduction of early stent thrombosis and in-stent restenosis is the improvement of biocompatibility of the devices. Diamond-like carbon is a novel material for coating stent surfaces in order to increase biocompatibility. The authors report on the endovascular treatment of two individuals with superficial femoral artery occlusions, using stents coated with diamond-like carbon. Technical and clinical success was achieved in both cases, with primary patency rates of 100% 12 months after intervention.

  7. Endovascular treatment of superficial femoral artery occlusive disease with stents coated with diamond-like carbon

    International Nuclear Information System (INIS)

    A major consideration in the reduction of early stent thrombosis and in-stent restenosis is the improvement of biocompatibility of the devices. Diamond-like carbon is a novel material for coating stent surfaces in order to increase biocompatibility. The authors report on the endovascular treatment of two individuals with superficial femoral artery occlusions, using stents coated with diamond-like carbon. Technical and clinical success was achieved in both cases, with primary patency rates of 100% 12 months after intervention

  8. Field emission from hybrid diamond-like carbon and carbon nanotube composite structures.

    Science.gov (United States)

    Zanin, H; May, P W; Hamanaka, M H M O; Corat, E J

    2013-12-11

    A thin diamond-like carbon (DLC) film was deposited onto a densely packed "forest" of vertically aligned multiwalled carbon nanotubes (VACNT). DLC deposition caused the tips of the CNTs to clump together to form a microstructured surface. Field-emission tests of this new composite material show the typical low threshold voltages for carbon nanotube structures (2 V μm(-1)) but with greatly increased emission current, better stability, and longer lifetime. PMID:24224845

  9. Mechanical and Surface Characterization of Diamond-Like Carbon Coatings onto Polymeric Substrate

    OpenAIRE

    Martí-González, Joan; Bertran, Enric

    2015-01-01

    In this master thesis, diamond-like carbon DLC/Cr bilayer systems, with thickness up to 1278 nm were formed on ABS, glass and Si substrates. Substrates surface were prepared by oxygen plasma cleaning process. The chromium thin film, which acts as a buffer layer, was grown by magnetron sputtering deposition. Diamond-like carbon was deposited by pulsed-DC PECVD, with methane and hydrogen as reactants. A Plackett-Burman experimental design was carried out in order to determine the influence of t...

  10. Studies of diamond-like carbon and diamond-like carbon polymer hybrid coatings deposited with filtered pulsed arc discharge method for biomedical applications

    OpenAIRE

    Soininen, Antti

    2015-01-01

    Hydrogen free diamond-like carbon (DLC) coatings have been the subject of investigation all around the world for the last 30 years. One of the major problems in producing of thick high-quality DLC coatings has been the inadequate adhesion of the deposited film to the substrate. This obstacle is finally overcome by depositing an intermediate adhesion layer produced with high energy (>2 keV) carbon plasma before application of a high-quality coating produced with a low energy unit. To the best ...

  11. Flexible diamond-like carbon thin film coated on rubbers: fundamentals and applications

    NARCIS (Netherlands)

    Pei, Yutao

    2015-01-01

    Dynamic rubber seals are the major source of friction in lubrication systems and bearings, which may take up to 70% of the total friction. Our solution is to coat rubbers with flexible diamond-like carbon (DLC) thin film by which the coefficient of friction is reduced from above 1.5 to below 0.15. C

  12. Selective formation of diamond-like carbon coating by surface catalyst patterning

    DEFF Research Database (Denmark)

    Palnichenko, A.V.; Mátéfi-Tempfli, M.; Mátéfi-Tempfli, Stefan;

    2004-01-01

    The selective formation of diamond-like carbon coating by surface catalyst patterning was studied. DLC films was deposited using plasma enhanced chemical vapor deposition, filtered vacuum arc deposition, laser ablation, magnetron sputtering and ion-beam lithography methods. The DLC coatings were...

  13. Diamond-like carbon coatings for orthopaedic applications: an evaluation of tribological performance.

    Science.gov (United States)

    Xu, T; Pruitt, L

    1999-02-01

    A detailed investigation of the tribological behaviour of vacuum arc diamond-like carbon coated Ti-6Al-4V against a medical grade ultra-high molecular weight polyethylene is conducted in this work in order to investigate the potential use of diamond-like carbon coatings for orthopaedic appplications. Lubricated and non-lubricated wear experiments are performed using a standard pin-on-disc wear tester. The coefficient of friction is monitored continuously during testing and wear rate calculations are performed using surface profilometry measurements of worn disc surfaces. Sliding wear tests show the existence of two distinct friction and wear regimes distinguished by physically different mechanisms. In the first stages of wear, adhesion and abrasion are the dominant mechanisms of wear while fatigue processes are activated later in the tests. The effects of diamond-like carbon coating structure, surface roughness and lubrication on tribological behaviour are presented. Optimal process-structure-property design for vacuum arc plasma deposition is utilized in order to obtain strong adhesion to the titanium alloy substrate. Diamond-like carbon coatings significantly improve the friction and wear performance of the orthopaedic bearing pair and show exceptional promise for biomedical applications. PMID:15347929

  14. Modification of rubber surface with hydrogenated diamond-like carbon thin films

    NARCIS (Netherlands)

    Pei, Y. T.; Bui, X. L.; De Hosson, J. Th. M.; Laudon, M; Romanowicz, B

    2009-01-01

    Thin films of hydrogenated diamond-like carbon (DLC) have been deposited on hydrogenated nitrile butadiene rubber (HNBR) for reduction of friction and enhancement of wear resistance of dynamic rubber seals, by sputtering graphite targets in C(2)H(2)/Ar plasma. The wax removal and pre-deposition plas

  15. Bacterial Adhesion to Diamond-like Carbon as Compared to Stainless Steel

    NARCIS (Netherlands)

    Soininen, Antti; Tiainen, Veli-Matti; Konttinen, Yrjo T.; van der Mei, Henny C.; Busscher, Henk J.; Sharma, Prashant K.

    2009-01-01

    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 s

  16. In vitro adhesion of staphylococci to diamond-like carbon polymer hybrids under dynamic flow conditions.

    Science.gov (United States)

    Soininen, Antti; Levon, Jaakko; Katsikogianni, Maria; Myllymaa, Katja; Lappalainen, Reijo; Konttinen, Yrjö T; Kinnari, Teemu J; Tiainen, Veli-Matti; Missirlis, Yannis

    2011-03-01

    This study compares the ability of selected materials to inhibit adhesion of two bacterial strains commonly implicated in implant-related infections. These two strains are Staphylococcus aureus (S-15981) and Staphylococcus epidermidis (ATCC 35984). In experiments we tested six different materials, three conventional implant metals: titanium, tantalum and chromium, and three diamond-like carbon (DLC) coatings: DLC, DLC-polydimethylsiloxane hybrid (DLC-PDMS-h) and DLC-polytetrafluoroethylene hybrid (DLC-PTFE-h) coatings. DLC coating represents extremely hard material whereas DLC hybrids represent novel nanocomposite coatings. The two DLC polymer hybrid films were chosen for testing due to their hardness, corrosion resistance and extremely good non-stick (hydrophobic and oleophobic) properties. Bacterial adhesion assay tests were performed under dynamic flow conditions by using parallel plate flow chambers (PPFC). The results show that adhesion of S. aureus to DLC-PTFE-h and to tantalum was significantly (P coating showed as low susceptibility to S. aureus adhesion as all the tested conventional implant metals. The adherence of S. epidermidis to biomaterials was not significantly (P coating without increasing the risk of implant-related infections. PMID:21243516

  17. Preparation and Investigation of Diamond-like Carbon Stripper Foils

    Institute of Scientific and Technical Information of China (English)

    FAN; Qi-wen; DU; Ying-hui; ZHANG; Rong; XU; Guo-ji

    2013-01-01

    1 Preparation of DLC stripper foils For DLC stripper foils of about 5μg/cm2 thickness,the following methods were used.The DLC foils of about 4μg/cm2 thicknesses were produced by FCVA onto glass slides coated with betaine-saccharose as releasing agent,which was previously covered with the evaporated carbon layers of about 1μg/cm2

  18. Diamond-like carbon formation for various positions by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yap, Seong-Shan [Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia)]. E-mail: ssyap@mmu.edu.my; Tou, Teck-Yong [Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia)

    2005-07-30

    Pulsed laser ablation of pyrolytic graphite target was carried out by an Nd-YAG laser with {lambda} = 1064 nm and fluence in the range of 1-10 J/cm{sup 2}. The plume was produced by focusing the laser beam and rastering over a 6.5 mm x 6.5 mm area on the graphite target. The substrates were placed at two positions: on-axis position facing the target and off-axis position in the target plane with 2 mm offset from the ablation site. Diamond-like carbon was formed on the substrates at both positions and on the ablated area as detected by Raman spectroscopy. Rough and granular surface was observed for the samples placed in the target plane and smooth diamond-like carbon films for the samples placed facing the target as observed by SEM and optical microscopy.

  19. Nanostructured Diamond-Like Carbon Films Grown by Off-Axis Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Seong Shan Yap

    2015-01-01

    Full Text Available Nanostructured diamond-like carbon (DLC films instead of the ultrasmooth film were obtained by pulsed laser ablation of pyrolytic graphite. Deposition was performed at room temperature in vacuum with substrates placed at off-axis position. The configuration utilized high density plasma plume arriving at low effective angle for the formation of nanostructured DLC. Nanostructures with maximum size of 50 nm were deposited as compared to the ultrasmooth DLC films obtained in a conventional deposition. The Raman spectra of the films confirmed that the films were diamond-like/amorphous in nature. Although grown at an angle, ion energy of >35 eV was obtained at the off-axis position. This was proposed to be responsible for subplantation growth of sp3 hybridized carbon. The condensation of energetic clusters and oblique angle deposition correspondingly gave rise to the formation of nanostructured DLC in this study.

  20. PROPERTIES OF DIAMOND-LIKE CARBON COATINGS DEPOSITED ON CoCrMo ALLOYS

    OpenAIRE

    Madej, Monika; Ozimina, Dariusz; Kurzydłowski, Krzysztof; Płociński, Tomasz; Wieciński, Piotr; Styp-Rekowski, Michał; Matuszewski, Maciej

    2015-01-01

    This paper presents results of the structure analysis and tribological testing of a-C:H type diamond-like carbon (DLC) coatings produced by the Plasma Assisted Chemical Vapour Deposition (PACVD) technology on CoCrMo specimens. The DLC coating structure was studied by observing the surface topography using a scanning electron microscope (SEM) in the SE and STEM modes and a profilometer. Raman spectroscopy provided information on hybridized covalent bonds. The structural analysis involved obser...

  1. Improved wear performance of ultra high molecular weight polyethylene coated with hydrogenated diamond like carbon

    OpenAIRE

    Puértolas, J. A.; Martínez-Nogués, V.; Martínez-Morlanes, M. J.; Mariscal, M. D.; Medel, F. J.; López-Santos, Carmen; Yubero, Francisco

    2010-01-01

    Hydrogenated diamond like carbon (DLCH) thin films were deposited on medical grade ultra high molecular weight polyethylene (UHMWPE) by radio frequency plasma enhanced chemical vapor deposition. The DLCH coating thicknesses ranged from 250 to 700. nm. The substrates were disks made of UHMWPEs typically used for soft components in artificial joints, namely virgin GUR 1050 and highly crosslinked (gamma irradiated in air to 100. kGy) UHMWPEs. Mechanical and tribological properties under bovine s...

  2. Characterisation of Diamond-Like Carbon (DLC) laser targets by Raman spectroscopy

    Science.gov (United States)

    Haddock, D.; Parker, T.; Spindloe, C.; Tolley, M.

    2016-04-01

    The search for target materials suitable for High Power Laser Experiments at ultralow thicknesses (below ten nanometres) is ongoing. Diamond-Like Carbon is investigated as an answer for a low-Z material that can survive target chamber pump-down and laser prepulse. DLC was produced using Plasma-Enhanced Chemical Vapour Deposition, using with varying gas flow mixtures of argon and methane. The methane plasma deposits amorphous carbon onto the substrate and the argon plasma re-sputters the weakly bonded carbon leaving a high proportion of diamond-like bonding. Bonding natures were probed using Raman spectroscopy; analysis of the resulting spectrum showed that flow rates of 40sccm/60sccm methane to argon produced DLC films with a diamond-like (sp 3) content of ∼20%. Increasing the methane gas flow decreased this value to less than 5%. DLC foils were processed into laser targets by method of float off; using a sodium chloride release layer and lowering into water, this was then lifted onto an array of apertures allowing for laser irradiation of the material with no backing. DLC with 20% sp 3 content showed superior yield when compared to other materials such as metals and some plastics of the same thickness, with ∼70% of the target positions surviving the float off procedure at <10nm. As a result of this work DLC targets have been available for a number of experiments at the Central Laser Facility.

  3. Study of facing target sputtered diamond-like carbon overcoats for hard disk drive media

    Energy Technology Data Exchange (ETDEWEB)

    Seet, H.L., E-mail: SEET_Hang_Li@dsi.a-star.edu.sg [Data Storage Institute, A*STAR Agency for Science, Technology and Research, 5 Engineering Drive 1, 117608 (Singapore); Ng, K.K.; Chen, X.Y. [Data Storage Institute, A*STAR Agency for Science, Technology and Research, 5 Engineering Drive 1, 117608 (Singapore); Yang, P. [Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603 (Singapore); Shen, L. [Institute of Materials Research and Engineering, A*STAR Agency for Science, Technology and Research, 3 Research Link, 117602 (Singapore); Ji, R.; Ng, H.X.; Lim, C.B. [Data Storage Institute, A*STAR Agency for Science, Technology and Research, 5 Engineering Drive 1, 117608 (Singapore)

    2015-07-01

    The demand for higher areal density in the hard disk drive industry has fuelled extensive research efforts and focuses on magnetic spacing reduction. In the head–disk interface arena, one of the key focuses is to reduce the carbon overcoat thickness without compromising the overcoat protection performance. Thus, in the search for alternative methods to reduce the carbon overcoat thickness, the facing target sputtering (FTS) process for diamond-like carbon deposition has been investigated. The resulting properties have been presented in this paper, with comparison to conventional diamond-like carbon (DLC) layers by other processes such as chemical vapor deposition and reactive sputtering with nitrogen. X-ray reflectometry results showed that facing target sputtered DLC samples displayed significantly higher density, at 2.87 g/cm{sup 3}, as compared to hydrogenated and nitrogenated DLC samples. This was attributed to the higher sp{sup 3} content, as obtained by X-ray photoelectron spectroscopy measurements. As a result of the high sp{sup 3} content, hardness of the FTS deposited samples was higher than that of the hydrogenated and nitrogenated DLC samples. In addition, the surface energy of FTS samples was observed to be comparable, but lower, than that of nitrogenated DLC samples through contact angle measurements. Clearances comparable to that of conventional DLC samples were achieved and the sample disks were flyable. Wear performance tests also revealed more wear resistance for the FTS deposited DLC samples, but also higher head wear. - Highlights: • Facing target sputtered (FTS) diamond-like carbon (DLC) samples were studied. • FTS DLC samples possess higher density and hardness. • Surface conditions and flyability performances for FTS DLC samples were comparable. • Wear tests on FTS DLC samples showed lower media wear, but higher head wear.

  4. Visible photoluminescence from ZnO/diamond-like carbon thin films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-chun; LI Qing-shan; DONG Yan-feng; MA Zi-xia

    2012-01-01

    ZnO/diamond-like carbon (DLC) thin films are deposited by pulsed laser deposition (PLD) on Si (111) wafer.Visible room-temperature photoluminescence (PL) is observed from ZnO/DLC thin films by fluorescence spectrophotometer.The Gaussian curve fitting of PL spectra reveals that the broadband visible emission contains three components with λ=508 nm,554 nm and 698 nm.The origin and possible mechanism of the visible PL are discussed,and they can be attributed to the PL recombination of ZnO and DLC thin films.

  5. Control of tribological properties of diamond-like carbon films with femtosecond-laser-induced nanostructuring

    Science.gov (United States)

    Yasumaru, Naoki; Miyazaki, Kenzo; Kiuchi, Junsuke

    2008-02-01

    This paper reports tribological properties of diamond-like carbon (DLC) films nanostructured by femtosecond (fs) laser ablation. The nanostructure was formed in an area of more than 15 mm × 15 mm on the DLC surface, using a precise target-scan system developed for the fs-laser processing. The frictional properties of the DLC film are greatly improved by coating a MoS 2 layer on the nanostructured surface, while the friction coefficient can be increased by surface texturing of the nanostructured zone in a net-like patterning. The results demonstrate that the tribological properties of a DLC surface can be controlled using fs-laser-induced nanostructuring.

  6. Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies

    OpenAIRE

    De Barros Bouchet, M. I.; Matta, C.; Le-Mogne, Th.; Martin, J. Michel; Zhang, Q.; Goddard, W., III; Kano, M; Mabuchi, Y.; J Ye

    2007-01-01

    We report a unique tribological system that produces superlubricity under boundary lubrication conditions with extremely little wear. This system is a thin coating of hydrogen-free amorphous Diamond-Like-Carbon (denoted as ta-C) at 353 K in a ta-C/ta-C friction pair lubricated with pure glycerol. To understand the mechanism of friction vanishing we performed ToF-SIMS experiments using deuterated glycerol and 13C glycerol. This was complemented by first-principles-based computer simulations us...

  7. Diamond-like carbon coatings deposited by vacuum arc in artificial hip joints

    OpenAIRE

    Ren, Ying

    2014-01-01

         For biomedical application in the field of artificial hip joints diamond-like carbon (DLC) coatings have been widely studied due to their excellent mechanical, tribological and biological properties. At present the lifetime of such joints is just about 15 years and some (10%) of patients require second replacementent. In consequence, it is currently an urgent need to extend the life expectancy especially for younger patients under 50 years old. As is well known, the wear particles as the...

  8. The effect of RF power on tribological properties of the diamond-like carbon films

    International Nuclear Information System (INIS)

    DLC thin films were prepared by radio frequency (RF) plasma-enhanced chemical vapor deposition (PECVD) method on silicon substrates using methane (CH4), hydrogen (H2) and gas mixture. We have checked the influence of varying RF power on DLC film. The Raman spectroscopy shows the diamond-like carbon (DLC) amorphous structure of the films. AFM images show the surface roughness of the DLC film decrease with increasing RF power. Also, the friction coefficients were investigated by atomic force microscope (AFM) in friction force microscope (FFM) mode

  9. Morphological analysis and cell viability on diamond-like carbon films containing nanocrystalline diamond particles

    Science.gov (United States)

    Almeida, C. N.; Ramos, B. C.; Da-Silva, N. S.; Pacheco-Soares, C.; Trava-Airoldi, V. J.; Lobo, A. O.; Marciano, F. R.

    2013-06-01

    The coating of orthopedic prostheses with diamond like-carbon (DLC) has been actively studied in the past years, in order to improve mechanical, tribological properties and promote the material's biocompatibility. Recently, the incorporation of crystalline diamond nanoparticles into the DLC film has shown effective in combating electrochemical corrosion in acidic medias. This study examines the material's biocompatibility through testing by LDH release and MTT, on in vitro fibroblasts; using different concentrations of diamond nanoparticles incorporated into the DLC film. Propounding its potential use in orthopedics in order to increase the corrosion resistance of prostheses and improve their relationship with the biological environment.

  10. Deposition of diamond like carbon films by using a single ion gun with varying beam source

    Institute of Scientific and Technical Information of China (English)

    JIANG Jin-qiu; Chen Zhu-ping

    2001-01-01

    Diamond like carbon films have been successfully deposited on the steel substrate, by using a single ion gun with varying beam source. The films may appear blue, yellow and transparent in color, which was found related to contaminants from the sample holder and could be avoided. The thickness of the films ranges from tens up to 200 nanometers, and the hardness is in the range 20 to 30 GPa. Raman analytical results reveal the films are in amorphous structure. The effects of different beam source on the films structure are further discussed.

  11. Study of relationship between structure and transmittance of diamond-like carbon (DLC) films

    Institute of Scientific and Technical Information of China (English)

    LIN; Song-sheng; HOU; Hui-jun; ZHU; Xia-gao; YUAN; Zhen-hai; DAI; Da-huang; LI; Hong-wu

    2005-01-01

    In this paper, the transparent hard diamond-like carbon (DLC) films were deposited on glass substrate by magnetic confined radio-frequency plasma chemical vapor deposition. The structure of films was studied by Raman spectra and X-ray photoelectron spectra (XPS), the transmittance of films by Spectrophotometer. The mechanism of the influence of films structure on transmittance of the films was discussed. The results show that the thickness of films was lower than 100nm, and the transmittance was over 90% in 380-780 nm region. Discussion in theory on the influence of film structure on transmittance was correspondence to experiment results.

  12. Panel 2 - properties of diamond and diamond-like-carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Blau, P.J.; Clausing, R.E. [Oak Ridge National Lab., TN (United States); Ajayi, O.O.; Liu, Y.Y.; Purohit, A. [Argonne National Lab., IL (United States); Bartelt, P.F. [Deere & Co., Moline, IL (United States); Baughman, R.H. [Allied Signal, Morristown, NJ (United States); Bhushan, B. [Ohio State Univ., Columbus (United States); Cooper, C.V. [United Technologies Research Center, East Hartford, CT (United States); Dugger, M.T. [Sandia National Laboratories, Albuquerque, NM (United States); Freedman, A. [Aerodyne Research, Inc., Billerica, MA (United States); Larsen-Basse, J. [National Science Foundation, Washington, DC (United States); McGuire, N.R. [Caterpillar, Peoria, IL (United States); Messier, R.F. [Pennsylvania State Univ., University Park (United States); Noble, G.L.; Ostrowki, M.H. [John Crane, Inc., Morton Grove, IL (United States); Sartwell, B.D. [Naval Research Lab., Washington, DC (United States); Wei, R. [Colorado State Univ., Fort Collins (United States)

    1993-01-01

    This panel attempted to identify and prioritize research and development needs in determining the physical, mechanical and chemical properties of diamond and diamond-like-carbon films (D/DLCF). Three specific goals were established. They were: (1) To identify problem areas which produce concern and require a better knowledge of D/DLCF properties. (2) To identify and prioritize key properties of D/DLCF to promote transportation applications. (3) To identify needs for improvement in properties-measurement methods. Each of these goals is addressed subsequently.

  13. Preparation and Characteristics of Nanoscale Diamond-Like Carbon Films for Resistive Memory Applications

    Institute of Scientific and Technical Information of China (English)

    FU Di; XIE Dan; ZHANG Chen-Hui; ZHANG Di; NIU Jie-Bin; QIAN He; LIU Li-Tian

    2010-01-01

    @@ We propose diamond-like carbon(DLC)as the resistance change material for nonvolatile memory applications.Nanoscale DLC films are prepared by filtered cathodic vacuum arc technique and integrated to W/DLC/W structure devices.The deposited DLC film has a thickness of about 2O nm and high sp3 fraction content.Reversible bistable resistive switching from a high resistance state to a low resistance state,and vice versa,is observed under appropriate unipolar stimulation pulses.

  14. Microstructure and chemical bond evolution of diamond-like carbon films machined by femtosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing; Wang, Chunhui [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Liu, Yongsheng, E-mail: yongshengliu@nwpu.edu.cn [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Cheng, Laifei [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Li, Weinan [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 10068 (China); Zhang, Qing [Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072 (China); Yang, Xiaojun [State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 10068 (China)

    2015-06-15

    Highlights: • The machining depth was essentially proportional to the laser power. • The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. And the number of nanoparticles increased with the processing power as well. • It revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. • It showed that a great decrease of sp{sup 3}/sp{sup 2} after laser treatment. - Abstract: Femtosecond laser is of great interest for machining high melting point and hardness materials such as diamond-like carbon, SiC ceramic, et al. In present work, the microstructural and chemical bond evolution of diamond-like carbon films were investigated using electron microscopy and spectroscopy techniques after machined by diverse femtosecond laser power in air. The results showed the machining depth was essentially proportional to the laser power. The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. Considering the D and G Raman band parameters on the laser irradiation, it revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. X-ray photoelectron spectroscopy analysis showed a great decrease of sp{sup 3}/sp{sup 2} after laser treatment.

  15. Microstructure and chemical bond evolution of diamond-like carbon films machined by femtosecond laser

    International Nuclear Information System (INIS)

    Highlights: • The machining depth was essentially proportional to the laser power. • The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. And the number of nanoparticles increased with the processing power as well. • It revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. • It showed that a great decrease of sp3/sp2 after laser treatment. - Abstract: Femtosecond laser is of great interest for machining high melting point and hardness materials such as diamond-like carbon, SiC ceramic, et al. In present work, the microstructural and chemical bond evolution of diamond-like carbon films were investigated using electron microscopy and spectroscopy techniques after machined by diverse femtosecond laser power in air. The results showed the machining depth was essentially proportional to the laser power. The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. Considering the D and G Raman band parameters on the laser irradiation, it revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. X-ray photoelectron spectroscopy analysis showed a great decrease of sp3/sp2 after laser treatment

  16. Architectural design of diamond-like carbon coatings for long-lasting joint replacements.

    Science.gov (United States)

    Liu, Yujing; Zhao, Xiaoli; Zhang, Lai-Chang; Habibi, Daryoush; Xie, Zonghan

    2013-07-01

    Surface engineering through the application of super-hard, low-friction coatings as a potential approach for increasing the durability of metal-on-metal replacements is attracting significant attention. In this study innovative design strategies are proposed for the development of diamond-like-carbon (DLC) coatings against the damage caused by wear particles on the joint replacements. Finite element modeling is used to analyze stress distributions induced by wear particles of different sizes in the newly-designed coating in comparison to its conventional monolithic counterpart. The critical roles of architectural design in regulating stress concentrations and suppressing crack initiation within the coatings is elucidated. Notably, the introduction of multilayer structure with graded modulus is effective in modifying the stress field and reducing the magnitude and size of stress concentrations in the DLC diamond-like-carbon coatings. The new design is expected to greatly improve the load-carrying ability of surface coatings on prosthetic implants, in addition to the provision of damage tolerance through crack arrest.

  17. Characterization of the Diamond-like Carbon Based Functionally Gradient Film

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Diamond-like carbon coatings have been used as solid lubricating coatings in vacuum technology for their goodphysical and chemical properties. In this paper, the hybrid technique of unbalanced magnetron sputtering and plasmaimmersion ion implantation (PIll) was adopted to fabricate diamond-like carbon-based functionally gradient film,N/TiN/Ti(N,C)/DLC, on the 304 stainless steel substrate. The film was characterized by using Raman spectroscopyand glancing X-ray diffraction (GXRD), and the topography and surface roughness of the film was observed usingAFM. The mechanical properties of the film were evaluated by nano-indentation. The results showed that the surfaceroughness of the film was approximately 0.732 nm. The hardness and elastic modulus, fracture toughness andinterfacial fracture toughness of N/TiN/Ti(N,C)/DLC functionally gradient film were about 19.84 GPa, 190.03 GPa,3.75 MPa.m1/2 and 5.68 MPa@m1/2, respectively. Compared with that of DLC monolayer and C/TiC/DLC multilayer,this DLC gradient film has better qualities as a solid lubricating coating.

  18. Workshop on diamond and diamond-like-carbon films for the transportation industry

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, F.A.; Moores, D.K. [eds.

    1993-01-01

    Applications exist in advanced transportation systems as well as in manufacturing processes that would benefit from superior tribological properties of diamond, diamond-like-carbon and cubic boron nitride coatings. Their superior hardness make them ideal candidates as protective coatings to reduce adhesive, abrasive and erosive wear in advanced diesel engines, gas turbines and spark-ignited engines and in machining and manufacturing tools as well. The high thermal conductivity of diamond also makes it desirable for thermal management not only in tribological applications but also in high-power electronic devices and possibly large braking systems. A workshop has been recently held at Argonne National Laboratory entitled ``Diamond and Diamond-Like-Carbon Films for Transportation Applications`` which was attended by 85 scientists and engineers including top people involved in the basic technology of these films and also representatives from many US industrial companies. A working group on applications endorsed 18 different applications for these films in the transportation area alone. Separate abstracts have been prepared.

  19. The local crystallization in nanoscale diamond-like carbon films during annealing

    International Nuclear Information System (INIS)

    The local crystallization during annealing at 600 °C in nanoscale diamond-like carbon coatings films grown by pulsed vacuum-arc deposition method was observed using modern techniques of high-resolution transmission electron microscopy. The crystallites formed by annealing have a face-centred cubic crystal structure and grow in the direction [01¯1¯] as a normal to the film surface. The number and size of the crystallites depend on the initial values of the intrinsic stresses before annealing, which in turn depend on the conditions of film growth. The sizes of crystallites are 10 nm for films with initial compressive stresses of 3 GPa and 17 nm for films with initial compressive stresses of 12 GPa. Areas of local crystallization arising during annealing have a structure different from the graphite. Additionally, the investigation results of the structure of nanoscale diamond-like carbon coatings films using Raman spectroscopy method are presented, which are consistent with the transmission electron microscopy research results

  20. Synthesis of functional diamond-like carbon nanocomposite films containing titanium dioxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kuo-Cheng [Department of Chemical Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan (China); Hong, Franklin Chau-Nan, E-mail: hong@mail.ncku.edu.t [Department of Chemical Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Taiwan (China)

    2010-10-01

    Synthesis of diamond-like carbon (DLC) films with UV-induced-hydrophilicity function was studied by inductively-coupled plasma (ICP) chemical vapor deposition. Titanium tetraisopropoxide (TTIP) and oxygen gases were employed as the precursors to deposit diamond-like nanocomposite films containing titanium dioxide (TiO{sub 2}) nanoparticles. X-ray diffraction and high-resolution transmission electron microscopy revealed that TiO{sub 2} nanocrystallites were formed in the DLC films when oxygen concentration was higher than TTIP concentration during deposition. The DLC nanocomposite film was hydrophobic without ultraviolet (UV) irradiation, and became highly hydrophilic under UV irradiation, exhibiting the self-cleaning effect. A very broad peak centered at 1580 cm{sup -1} was observed in the Raman spectra confirming the formation of DLC films. The hardness of the film was about 8 GPa with a stress of 3 GPa. ICP was essential in forming the photocatalytic TiO{sub 2} nanoparticles in the DLC matrix.

  1. Synthesis and characterization of boron incorporated diamond-like carbon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L.L. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Yang, Q., E-mail: qiaoqin.yang@usask.ca [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Tang, Y.; Yang, L.; Zhang, C. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Hu, Y.; Cui, X. [Canadian Light Source Inc., 101 Perimeter Road, Saskatoon, SK S7N 0X4 (Canada)

    2015-08-31

    Boron incorporated diamond-like carbon (B-DLC) (up to 8 wt.% boron) thin films were synthesized on silicon wafers using biased target ion beam deposition technique, where diamond-like carbon (DLC) was deposited by ion beam deposition and boron (B) was simultaneously incorporated by biased target sputtering of a boron carbide (B{sub 4}C) target under different conditions. Pure DLC films and B–C films were also synthesized by ion beam deposition and biased target sputtering of B{sub 4}C under similar conditions, respectively, as reference samples. The microstructure and mechanical properties of the synthesized films have been characterized by various technologies. It has been found that B exists in different states in B-DLC, including carbon-rich and B-rich boron carbides, boron suboxide and boron oxide, and the oxidation of B probably occurs during the film deposition. The incorporation of B into DLC leads to the increase of sp{sup 3} bonded carbon in the films, the increase of both film hardness and elastic modulus, and the decrease of both surface roughness and friction coefficient. Furthermore, the content of sp{sup 3} bonded carbon, film hardness and elastic modulus increase, and the film surface roughness and friction coefficient decrease with the increase of B-rich carbide in the B-DLC films. - Highlights: • Biased target ion beam deposition technique is promising to produce high quality DLC based thin films; • Boron exists in different states in B-DLC thin films; • The incorporation of B to DLC with different levels leads to improved film properties; • The fraction of sp{sup 3} bonded C in B-DLC thin films increase with the increase of B-rich carbide content in the films.

  2. Low temperature crystallization of diamond-like carbon films to graphene

    Energy Technology Data Exchange (ETDEWEB)

    Tinchev, Savcho, E-mail: stinchev@ie.bas.bg [Institute of Electronics, Bulgarian Academy of Sciences, Tzarigradsko Chaussee 72, 1784 Sofia (Bulgaria); Valcheva, Evgenia [Physics Department, Sofia University, J. Bourchier 5, 1164 Sofia (Bulgaria); Petrova, Elitza [Institute of Electronics, Bulgarian Academy of Sciences, Tzarigradsko Chaussee 72, 1784 Sofia (Bulgaria)

    2013-09-01

    Plasma surface modification was used to fabricate graphene on the top of insulating diamond-like carbon films. It is shown that by a combination of pulsed argon plasma treatment and thermal annealing at 350{sup o}C it is possible to achieve crystallization of amorphous carbon to graphene. The observed Raman spectra are typical for defected graphene-splitted D- and G-peaks and a broad 2D-peak. Because interpretation of Raman spectra of such complicated system is not easy we have calculated Raman signals of graphene on an amorphous hydrogenated carbon film deposited on a Si substrate. Our simulation results show that multiple reflections and interference effects lead to enhancement of Raman signal of the system. The characteristic for graphene G and 2D bands reach maximal enhancement for thicknesses of the amorphous hydrogenated carbon film of about 75 nm and 230 nm. We estimate that the interference enhancement of the 2D graphene Raman signal is very weak in contrast to that of the G band signal simulated for the underlying diamond-like carbon films on silicon substrate only. Therefore experimentally measured Raman spectra of the whole graphene/a-C:H/Si system probably will consist of interference enhanced but still weak 2D graphene peak and stronger D and G peaks dominated by G and D Raman bands of the a-C:H. This conclusion is in line with observed experimental Raman spectra. Electrical field effect measurements of the samples show ambipolar dependence, typical for single-layer graphene.

  3. Atomic oxygen resistant behaviors of Mo/diamond-like carbon nanocomposite lubricating films

    International Nuclear Information System (INIS)

    Mo doped diamond-like carbon (Mo/DLC) films were deposited on Si substrates via unbalanced magnetron sputtering of molybdenum combined with plasma chemical vapor deposition of CH4/Ar. The microstructure of the films, characterized by transmission electron microscopy and selected area electron diffraction, was considered as a nanocomposite with nano-sized MoC particles uniformly embedded in the amorphous carbon matrix. The structure, morphology, surface composition and tribological properties of the Mo/DLC films before and after the atomic oxygen (AO) irradiation were investigated and a comparison made with the DLC films. The Mo/DLC films exhibited more excellent degradation resistant behaviors in AO environment than the DLC films, and the MoC nanoparticles were proved to play a critical role of preventing the incursion of AO and maintaining the intrinsic structure and excellent tribological properties of DLC films.

  4. Tribological properties of ion beam deposited diamond-like carbon film on silicon nitride

    International Nuclear Information System (INIS)

    The present article reports on the physical characterization and tribological properties of diamond-like carbon (DLC) films deposited on structural Si3N4 substrates. The films were deposited by the direct ion beam deposition technique. The ion beam was produced by plasma discharge of pre-mixed methane and hydrogen gas in a Kaufman-type ion source. The deposited films were found to be amorphous and contained about 70% carbon and 30% hydrogen. The friction coefficient of an uncoated Si3N4 ball on a DLC coated Si3N4 disc starts at about 0.2, then decreases rapidly to 0.1-0.15 with increasing sliding distance. Increasing humidity results in a slight increase in friction coefficient, but a significant decrease in wear factor. The wear factor for the tests at ≅60% rh (relative humidity) are about an order of magnitude smaller than the tests at 3% rh. (orig.)

  5. Diamond-Like Carbon Film Deposition Using DC Ion Source with Cold Hollow Cathode

    Directory of Open Access Journals (Sweden)

    E. F. Shevchenko

    2014-01-01

    Full Text Available Carbon diamond-like thin films on a silicon substrate were deposited by direct reactive ion beam method with an ion source based on Penning direct-current discharge system with cold hollow cathode. Deposition was performed under various conditions. The pressure (12–200 mPa and the plasma-forming gas composition consisting of different organic compounds and hydrogen (C3H8, CH4, Si(CH32Cl2, H2, the voltage of accelerating gap in the range 0.5–5 kV, and the substrate temperature in the range 20–850°C were varied. Synthesized films were researched using nanoindentation, Raman, and FTIR spectroscopy methods. Analysis of the experimental results was made in accordance with a developed model describing processes of growth of the amorphous and crystalline carbon materials.

  6. Patterned macroarray plates in comparison of bacterial adhesion inhibition of tantalum, titanium, and chromium compared with diamond-like carbon.

    Science.gov (United States)

    Levon, Jaakko; Myllymaa, Katja; Kouri, Vesa-Petteri; Rautemaa, Riina; Kinnari, Teemu; Myllymaa, Sami; Konttinen, Yrjö T; Lappalainen, Reijo

    2010-03-15

    Staphylococcus aureus device-related infection is a common complication in implantology. Bacterial adhesion on implant surfaces is the initial step in the infective process. The aim was to develop a method suitable for quantitative bacterial adherence studies and to test a new diamond-like carbon (DLC) coating against commonly used metallic biomaterials with regards to Staphylococcus aureus adhesion. Patterned silicon chips with spots of tantalum, titanium, chromium, and DLC were produced using ultraviolet lithography and physical vapor deposition. These patterned chips were used as such or glued to array plates, pretreated with serum and exposed to S. aureus (S-15981) for 90 min, followed by acridine orange staining and fluorescence microscopy. An adhesion index showed that the ranking order of the biomaterials was titanium, tantalum, chromium, and DLC, with the DLC being clearly most resistant against colonization with S. aureus. Micropatterned surfaces are useful for quantitative comparison of bacterial adherence on different biomaterials. In the presence of serum, DLC is superior in its ability to resist adhesion and colonization by S. aureus compared with the commonly used biomaterial metals tantalum, titanium, and chromium. PMID:19437436

  7. Diamond like carbon coatings deposited by microwave plasma CVD: XPS and ellipsometric studies

    Indian Academy of Sciences (India)

    R M Dey; M Pandey; D Bhattacharyya; D S Patil; S K Kulkarni

    2007-12-01

    Diamond-like carbon (DLC) films were deposited by microwave assisted chemical vapour deposition system using d.c. bias voltage ranging from –100 V to –300 V. These films were characterized by X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry techniques for estimating 3/2 ratio. The 3/2 ratio obtained by XPS is found to have an opposite trend to that obtained by spectroscopic ellipsometry. These results are explained using sub-plantation picture of DLC growth. Our results clearly indicate that the film is composed of two different layers, having entirely different properties in terms of void percentage and 3/2 ratio. The upper layer is relatively thinner as compared to the bottom layer.

  8. Low-emissivity coating of amorphous diamond-like carbon/Ag-alloy multilayer on glass

    International Nuclear Information System (INIS)

    Transparent low-emissivity (low-e) coatings comprising dielectrics of amorphous diamond-like carbon (DLC) and Ag-alloy films are investigated. All films have been prepared by dc magnetron sputtering. An index of refraction of the DLC film deposited in a gas mixture of Ar/H2 (4%) shows n = 1.80 + 0.047i at 500 nm wavelength. A multilayer stack of DLC (70 nm thick)/Ag87.5Cu12.5-alloy (10 nm)/DLC (140 nm)/Ag87.5Cu12.5-alloy (10 nm)/DLC (70 nm) has revealed clear interference spectra with spectra selectivity. This coating performs low emittance less than 0.1 for black body radiation at 297 K, exhibiting a transparent heat mirror property embedded in DLC films

  9. Electron-beam induced diamond-like-carbon passivation of plasmonic devices

    Science.gov (United States)

    Balaur, Eugeniu; Sadatnajafi, Catherine; Langley, Daniel; Lin, Jiao; Kou, Shan Shan; Abbey, Brian

    2015-12-01

    Engineered materials with feature sizes on the order of a few nanometres offer the potential for producing metamaterials with properties which may differ significantly from their bulk counterpart. Here we describe the production of plasmonic colour filters using periodic arrays of nanoscale cross shaped apertures fabricated in optically opaque silver films. Due to its relatively low loss in the visible and near infrared range, silver is a popular choice for plasmonic devices, however it is also unstable in wet or even ambient conditions. Here we show that ultra-thin layers of Diamond-Like Carbon (DLC) can be used to prevent degradation due to oxidative stress, ageing and corrosion. We demonstrate that DLC effectively protects the sub-micron features which make up the plasmonic colour filter under both atmospheric conditions and accelerated aging using iodine gas. Through a systematic study we confirm that the nanometre thick DLC layers have no effect on the device functionality or performance.

  10. Characterization and development of diamond-like carbon coatings for storing ultracold neutrons

    CERN Document Server

    Grinten, M G D; Shiers, D; Baker, C A; Green, K; Harris, P G; Iaydjiev, P S; Ivanov, S N; Geltenbort, P

    1999-01-01

    In order to determine the suitability of diamond-like carbon (DLC) as a material for storing ultracold neutrons to use in neutron electric-dipole moment (EDM) experiments, a number of tests on DLC coatings have been performed. Thin DLC layers deposited on quartz and aluminium substrates by chemical vapour deposition have been characterised by neutron transmission, neutron reflectometry, electron microscopy and neutron and mercury storage and depolarisation lifetime measurements. Two types of DLC have been compared; DLC made by chemical vapour deposition from natural methane and DLC made by chemical vapour deposition from deuterated methane. With these samples we determined the density, hydrogen concentration and Fermi potential of the coatings. DLC coatings made from deuterated methane are now successfully being used in an experiment to measure the EDM of the neutron.

  11. Tantalum as a buffer layer in diamond-like carbon coated artificial hip joints.

    Science.gov (United States)

    Kiuru, Mirjami; Alakoski, Esa; Tiainen, Veli-Matti; Lappalainen, Reijo; Anttila, Asko

    2003-07-15

    The acid resistance of tantalum coated and uncoated human hip joint prostheses was studied with commercial CrCoMo acetabular cups. The samples were exposed to 10% HCl solution and the quantities of dissolved Cr, Co, and Mo were measured with proton-induced X-ray emission (PIXE). The absolute quantities were obtained with the use of Cr and Se solution standards. Tantalum coatings (thicknesses 4-6 microm) were prepared in vacuum with magnetron sputtering. Tantalum coating decreased the corrosion rate by a factor of 10(6). As a spinoff from recent wear tests on artificial hip joints it was shown that tantalum has excellent mechanical properties as an intermediate layer of diamond-like carbon (DLC) coatings. When tantalum was tested together with DLC on three metal-on-metal hip joint pairs in a hip simulator, no observable defects occurred during 15 million walking cycles with a periodic 50-300-kg load (Paul curve). PMID:12808604

  12. Experimental Study of Diamond Like Carbon (DLC) Coated Electrodes for Pulsed High Gradient Electron Gun

    CERN Document Server

    Paraliev, M; Ivkovic, S; Le Pimpec, F

    2010-01-01

    For the SwissFEL Free Electron Laser project at the Paul Scherrer Institute, a pulsed High Gradient (HG) electron gun was used to study low emittance electron sources. Different metals and surface treatments for the cathode and anode were studied for their HG suitability. Diamond Like Carbon (DLC) coatings are found to perform exceptionally well for vacuum gap insulation. A set of DLC coated electrodes with different coating parameters were tested for both vacuum breakdown and photo electron emission. Surface electric fields over 250MV/m (350 - 400kV, pulsed) were achieved without breakdown. From the same surface, it was possible to photo-emit an electron beam at gradients up to 150MV/m. The test setup and the experimental results are presented

  13. Low-friction behaviour of boundary-lubricated diamond-like carbon coatings containing tungsten

    International Nuclear Information System (INIS)

    It is generally accepted and well described that the mechanism by which extreme-pressure (EP) and antiwear (AW) additives reduce the friction and wear of metallic surfaces under boundary lubrication is the formation of tribochemical films. Although investigations of diamond-like carbon (DLC)-coated surfaces showed improved tribological properties when lubricated by additivated oil, the mechanism responsible is not fully understood. Therefore, the aim of the investigation was to determine the mechanism responsible for the low-friction behaviour of W-containing DLC coatings when lubricated with polyalphaolefin (PAO) oil containing EP or AW additives and to obtain some further understanding to this important area. The results of the present investigation clearly show that low-friction behaviour of boundary-lubricated W-DLC coatings is governed by formation of WS2-containing tribofilms on the steel countersurface or exposed steel substrate, which reduce friction by up to 50%

  14. Influences of ultraviolet irradiation on structure and tribological properties of diamond-like carbon films

    International Nuclear Information System (INIS)

    Two types of diamond-like carbon (DLC) films with different bonding configurations were produced by pulse-assisted and DC-assisted plasma chemical vapor deposition. The chemical composition, surface morphology, microstructure, internal stress and tribological properties of the two films before and after the ultraviolet (UV) irradiation were investigated and compared. It was found that the UV irradiation had little effects on the chemical composition and surface morphology of both the films, but greatly influenced their tribological properties in the opposite trends. This result was attributed to the different changing outcomes of the bonding configuration induced by the UV actions of primary photo-dissociation and secondary recombination, wherein the inherent bonding configuration and internal stress played important roles.

  15. Synthesis and tribological properties of diamond-like carbon films by electrochemical anode deposition

    Science.gov (United States)

    Li, Yang; Zhang, GuiFeng; Hou, XiaoDuo; Deng, DeWei

    2012-06-01

    Diamond-like carbon films (DLC) are deposited on Ti substrate by electrochemical anodic deposition at room temperature in pure methanol solution using a pulsed DC voltage at a range from 200 V to 2000 V. Raman spectroscopy analysis of the films reveals two broaden characteristic absorption peaks centred at ˜1350 cm-1 and 1580 cm-1, relating to D- and G-band of typical DLC films, respectively. A broad peak centred at 1325-1330 cm-1 is observed when an applied potential is 1200 V, which can confirm that the deposited films contained diamond structure phase. Tribological properties of the coated Ti substrates have been measured by means of a ball-on-plate wear test machine. A related growth mechanism of DLC films by the anodic deposition mode has also been discussed.

  16. Hydrogenated diamond-like carbon film deposited on UHMWPE by RF-PECVD

    International Nuclear Information System (INIS)

    In this work, investigations were conducted to analyze the properties of diamond-like carbon (DLC) film deposited on ultra-high molecular weight polyethylene (UHMWPE) by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) at a low temperature of 50 deg. C. Composition and structure of the films were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. Hardness and wettability of the film were tested. Tribological characterizations were carried out on a universal micro-tribometer, and reciprocating friction against ZrO2 ball was adopted with 25% bovine serum as lubrication. Results show that DLC film was successfully deposited on UHMWPE surface by RF-PECVD and the sp3 content was about 20% in the film. The film increased the macrohardness of the substrate by about 42% and the wettability was improved too. Tribology test showed a higher friction coefficient but a much smaller wear volume after the deposition due to the surface roughening and strengthening.

  17. Structure and mechanical properties of tungsten-containing hydrogenated diamond like carbon coatings for space applications

    Science.gov (United States)

    Jun, Zheng; Hui, Zhou; Zhi-hua, Wan; Rui-peng, Sang

    Tungsten-containing diamond like carbon (W-C:H) coatings were prepared by unbalanced magnetron sputtering (UBM) using tungsten carbide targets in Ar/C2H2 atmosphere. The structure and mechanical properties of these coatings with different C2H2 flow (from 40 sccm to 140 sccm) were studied. According to the analysis of Raman spectroscopy and the measurement of hardness and Young's modulus about the coatings, it was showed that sp3/sp2 ratio in the coatings changed and the hardness and Young's modulus decreased with increase of the C2H2 flow. Besides, the adhension and friction wear properties of the coatings were evaluated using the scratch test and dry sliding tests respectively. It was found that the coatings exhibited very good adhension and the C2H2 flow (actually the hydrogen) played a very important role in the tribological behavior of the W-C:H coatings in vacuum.

  18. In Vitro Durability - Pivot bearing with Diamond Like Carbon for Ventricular Assist Devices

    CERN Document Server

    de Sá, Rosa Corrêa Leoncio; Leão, Tarcísio Fernandes; da Silva, Evandro Drigo; da Fonseca, Jeison Willian Gomes; da Silva, Bruno Utiyama; Leal, Edir Branzoni; Moro, João Roberto; de Andrade, Aron José Pazin; Bock, Eduardo Guy Perpétuo

    2015-01-01

    Institute Dante Pazzanese of Cardiology (IDPC) develops Ventricular Assist Devices (VAD) that can stabilize the hemodynamics of patients with severe heart failure before, during and/or after the medical practice; can be temporary or permanent. The ADV's centrifugal basically consist of a rotor suspended for system pivoting bearing; the PIVOT is the axis with movement of rotational and the bearing is the bearing surface. As a whole system of an implantable VAD should be made of long-life biomaterial so that there is no degradation or deformation during application time; surface modification techniques have been widely studied and implemented to improve properties such as biocompatibility and durability of applicable materials. The Chemical Vapour Deposition technique allows substrates having melting point higher than 300 {\\deg}C to be coated, encapsulated, with a diamond like carbon film (DLC); The test simulated the actual conditions in which the system of support remains while applying a ADV. The results hav...

  19. Oxygen plasma etching of silver-incorporated diamond-like carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Marciano, F.R., E-mail: fernanda@las.inpe.b [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010, SP (Brazil); Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial (CTA), Pca. Marechal Eduardo Gomes, 50-Sao Jose dos Campos, 12228-900, SP (Brazil); Bonetti, L.F. [Clorovale Diamantes Industria e Comercio Ltda, Estr. do Torrao de Ouro, 500-Sao Jose dos Campos, 12229-390, SP (Brazil); Pessoa, R.S.; Massi, M. [Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial (CTA), Pca. Marechal Eduardo Gomes, 50-Sao Jose dos Campos, 12228-900, SP (Brazil); Santos, L.V.; Trava-Airoldi, V.J. [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010, SP (Brazil)

    2009-08-03

    Diamond-like carbon (DLC) film as a solid lubricant coating represents an important area of investigation related to space devices. The environment for such devices involves high vacuum and high concentration of atomic oxygen. The purpose of this paper is to study the behavior of silver-incorporated DLC thin films against oxygen plasma etching. Silver nanoparticles were produced through an electrochemical process and incorporated into DLC bulk during the deposition process using plasma enhanced chemical vapor deposition technique. The presence of silver does not affect significantly DLC quality and reduces by more than 50% the oxygen plasma etching. Our results demonstrated that silver nanoparticles protect DLC films against etching process, which may increase their lifetime in low earth orbit environment.

  20. Stress reduction of Cu-doped diamond-like carbon films from ab initio calculations

    Directory of Open Access Journals (Sweden)

    Xiaowei Li

    2015-01-01

    Full Text Available Structure and properties of Cu-doped diamond-like carbon films (DLC were investigated using ab initio calculations. The effect of Cu concentrations (1.56∼7.81 at.% on atomic bond structure was mainly analyzed to clarify the residual stress reduction mechanism. Results showed that with introducing Cu into DLC films, the residual compressive stress decreased firstly and then increased for each case with the obvious deterioration of mechanical properties, which was in agreement with the experimental results. Structural analysis revealed that the weak Cu-C bond and the relaxation of both the distorted bond angles and bond lengths accounted for the significant reduction of residual compressive stress, while at the higher Cu concentration the increase of residual stress attributed to the existence of distorted Cu-C structures and the increased fraction of distorted C-C bond lengths.

  1. Fabrication of Diamond-like Carbon Films by Ion Assisted Middle Frequency Unbalanced Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-chen; SUN Shao-ni; ZHOU Yi; MA Sheng-ge; BA De-chun

    2006-01-01

    Diamond-like carbon (DLC) films are deposited by the Hall ion source assisted by the mid-frequency unbalanced magnetron sputtering technique. The effects of the substrate voltage bias, the substrate temperature, the Hall discharging current and the argon/nitrogen ratio on the DLC film's performance were studied. The experimental results show that the film's surface roughness, the hardness and the Young's modulus increase firstly and then decrease with the bias voltage incrementally increases. Also when the substrate temperature rises, the surface roughness of the film varies slightly, but its hardness and Young's modulus firstly increase followed by a sharp decrease when the temperature surpassing 120 ℃. With the Hall discharging current incrementally rising, the hardness and Young's modulus of the film decrease and the surface roughness of the film on 316L stainless steel firstly decreased and then remains constant.

  2. Properties of Diamond-Like Carbon Films Synthesized by Dual-Target Unbalanced Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    LIU Cui; LI Guo-Qing; GOU Wei; MU Zong-Xin; ZHANG Cheng-Wu

    2004-01-01

    @@ Smooth, dense and uniform diamond-like carbon films (DLC films) for industrial applications have successfully been prepared by dual-target unbalanced magnetron sputtering and the DLC characteristics of the films are confirmed by Raman spectra. It is found that the sputtering current of target plays an important role in the DLC film deposition. Deposition rate of 3.5μm/h is obtained by using the sputtering current of 30 A. The friction coefficient of the films is 0.2-0.225 measured by using a pin-on-disc microtribometer. The structure of the films tends to have a growth of sp3 bonds content at high sputtering current. The compressive residual stress in the films increases with the increasing sputtering current of the target.

  3. Characterization of diamond-like carbon films by SEM, XRD and Raman spectroscopy

    International Nuclear Information System (INIS)

    Diamond-like carbon films were deposited by electrolysis of a water-ethanol solution on Cu at low voltages (60-100 V) at 2 mm interelectrode separation. The films were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD) and Raman spectroscopy. The films were found to be continuous and compact with uniform grain distribution. Raman spectroscopy analysis revealed two broad bands at ∼1350 and ∼1580 cm-1. The downshift of the G band of graphite is indicative of the presence of DLC. For XRD analysis, the three strong peaks located at 2θ values of 43.2 deg., 74.06 deg. and 89.9 deg. can be identified with reflections form (1 1 1), (2 2 0) and (3 1 1) plane of diamond.

  4. Ion-implanted Mechanism of the Deposition Process for Diamond-Like Carbon Films

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-Min; WU Wei-Dong; WANG Yu-Ying; WANG Hai-Ping; GE Fang-Fang; TANG Yong-Jian; JU Xin

    2011-01-01

    Due to the local densification, high-energy C and doped ions can greatly affect the bonding configurations of diamond-like carbon films. We investigate the corresponding affection of different incident ions with energy from WeV to 600eV by Monte Carlo methods. The ion-implanted mechanism called the subplantation (for C, N, O, W, Y, etc.) is confirmed. Obvious thermal effect could be induced by the subplantation of the incident ions. Further, the subplantation of C ions is proved by in situ reflection high energy electron diffraction (RHEED). The observation from an atomic force microscope (AFM) indicates that the initial implantation of C ions might result in the final primitive-cell-like morphology of the smooth film (in an area of 1.2 mm × 0.9 mm, rms roughness smaller than 20 nm by Wyko).

  5. Tribological Characteristic of Diamond-like Carbon Films Investigated by Lateral Force Microscope

    Institute of Scientific and Technical Information of China (English)

    DINGJian-ning; ZHUShou-xing; FANZhen; LIChang-sheng; CAILan; YANGJi-chang

    2004-01-01

    Tribological characteristic of different thick diamond- like carbon (DLC) fihns was stymied. A geometrical method was applied to calibrate the cantilever spring constant and to calculate tbe normal and lateral forces, respectively. Experimental results show that the lateral force under different applied loads is proportional to the normal force for the DLC films with the thickness of 153.4nm and 64.9nm. However, for the thickness of 4.48nm and 2.78nm DLC films, lateral force is nonlinear to normal force, which is opposed to the Amonton's law. The single asperity regime and the DMT model were put forward to predict the possible nanotribological mecb-anism between the probe and DLC film.

  6. Role of atomic transverse migration in growth of diamond-like carbon films

    Institute of Scientific and Technical Information of China (English)

    Ma Tian-Bao; Hu Yuan-Zhong; Wang Hui

    2007-01-01

    The growth of diamond-like carbon (DLC) films is studied using molecular dynamics simulations. The effect of impact angle on film structure is carefully studied, which shows that the transverse migration of the incident atoms is the main channel of film relaxation. A transverse-migration-induced film relaxation model is presented to elucidate the process of film relaxation which advances the original model of subplantation. The process of DLC film growth on a rough surface is also investigated, as well as the evolution of microstructure and surface morphology of the film. A preferential-to-homogeneous growth mode and a smoothing of the film are observed, which are due to the transverse migration of the incident atoms.

  7. Kinetics and thermodynamics of human serum albumin adsorption on silicon doped diamond like carbon

    International Nuclear Information System (INIS)

    To gain a better understanding of protein adsorption onto biomaterial surfaces is required for the control of biocompatibility and bioactivity. Various samples of diamond like carbon (DLC) and silicon-doped DLC were synthesised using plasma enhanced chemical vapour deposition (PECVD). The effects of surface morphology on the interaction of human serum albumin (HSA) with doped and undoped DLC films was investigated using spectroscopic ellipsometry (SE) and other surface analysis techniques. The results highlighted an increase in both contact angle and hydrophobicity with increasing silicon dopant levels. A reduction on the contact angle values. After adsorption of HSA, the films showed a reduction in the contact angle with a significant change in the cosΔ and this gap increased with increasing surface coverage of HSA. The adsorption kinetics of HSA were also investigated and revealed that the maximum adsorption occurred at pH 5.0 and the process involved chemisorption. The experimental isotherm data were analysed using the Langmuir and Freundlich‎ models. The amount of HSA adsorbed increased with contact time and reached saturation ‎after 30 min. The adsorption ‎process was found to be pseudo first order with respect to the bulk concentration and was dependent on both the concentration of protein and surface characteristics of the samples. The amount of adsorbed HSA was higher with higher levels of silicon doping of the DLC. Therefore, doping DLC may provide an approach to controlling the protein adsorption. - Graphical abstract: The average thickness layer of HSA measurement onto surfaces of DLC and Si-DLC. - Highlights: • Diamond Like Carbon (DLC) and Silicon doped DLC were synthesised and characterised. • Si-DLC increases the hydrophobicity and decreases the surface free energy. • Adsorption study using human serum albumin (HSA). • The adsorbed amount of HSA increases with increasing of Silicon content DLC. • Adsorption process follow pseudo

  8. Kinetics and thermodynamics of human serum albumin adsorption on silicon doped diamond like carbon

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Mukhtar H., E-mail: ahmed-m@email.ulster.ac.uk; Byrne, John A.; McLaughlin, James

    2015-03-15

    To gain a better understanding of protein adsorption onto biomaterial surfaces is required for the control of biocompatibility and bioactivity. Various samples of diamond like carbon (DLC) and silicon-doped DLC were synthesised using plasma enhanced chemical vapour deposition (PECVD). The effects of surface morphology on the interaction of human serum albumin (HSA) with doped and undoped DLC films was investigated using spectroscopic ellipsometry (SE) and other surface analysis techniques. The results highlighted an increase in both contact angle and hydrophobicity with increasing silicon dopant levels. A reduction on the contact angle values. After adsorption of HSA, the films showed a reduction in the contact angle with a significant change in the cosΔ and this gap increased with increasing surface coverage of HSA. The adsorption kinetics of HSA were also investigated and revealed that the maximum adsorption occurred at pH 5.0 and the process involved chemisorption. The experimental isotherm data were analysed using the Langmuir and Freundlich‎ models. The amount of HSA adsorbed increased with contact time and reached saturation ‎after 30 min. The adsorption ‎process was found to be pseudo first order with respect to the bulk concentration and was dependent on both the concentration of protein and surface characteristics of the samples. The amount of adsorbed HSA was higher with higher levels of silicon doping of the DLC. Therefore, doping DLC may provide an approach to controlling the protein adsorption. - Graphical abstract: The average thickness layer of HSA measurement onto surfaces of DLC and Si-DLC. - Highlights: • Diamond Like Carbon (DLC) and Silicon doped DLC were synthesised and characterised. • Si-DLC increases the hydrophobicity and decreases the surface free energy. • Adsorption study using human serum albumin (HSA). • The adsorbed amount of HSA increases with increasing of Silicon content DLC. • Adsorption process follow pseudo

  9. Surface properties of diamond-like carbon films prepared by CVD and PVD methods

    Institute of Scientific and Technical Information of China (English)

    Liu Dong-Ping; Liu Yan-Hong; Chen Bao-Xiang

    2006-01-01

    Diamond-like carbon (DLC) films have been deposited using three different techniques: (a) electron cyclotron resonance-plasma source ion implantation, (b) low-pressure dielectric barrier discharge, (c) filtered-pulsed cathodic arc discharge. The surface and mechanical properties of these films are compared using atomic force microscopebased tests. The experimental results show that hydrogenated DLC films are covered with soft surface layers enriched with hydrogen and sp3 hybridized carbon while the soft surface layers of tetrahedral amorphous carbon (ta-C) films have graphite-like structure. The formation of soft surface layers can be associated with the surface diffusion and growth induced by the low-energy deposition process. For typical CVD methods, the atomic hydrogen in the plasmas can contribute to the formation of hydrogen and sp3 hybridized carbon enriched surface layers. The high-energy ion implantation causes the rearrangement of atoms beneath the surface layer and leads to an increase in film density. The ta-C films can be deposited using the medium energy carbon ions in the highly-ionized plasma.

  10. Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies

    International Nuclear Information System (INIS)

    We report a unique tribological system that produces superlubricity under boundary lubrication conditions with extremely little wear. This system is a thin coating of hydrogen-free amorphous Diamond-Like-Carbon (denoted as ta-C) at 353 K in a ta-C/ta-C friction pair lubricated with pure glycerol. To understand the mechanism of friction vanishing we performed ToF-SIMS experiments using deuterated glycerol and 13C glycerol. This was complemented by first-principles-based computer simulations using the ReaxFF reactive force field to create an atomistic model of ta-C. These simulations show that DLC with the experimental density of 3.24 g/cc leads to an atomistic structure consisting of a 3D percolating network of tetrahedral (sp3) carbons accounting for 71.5% of the total, in excellent agreement with the 70% deduced from our Auger spectroscopy and XANES experiments. The simulations show that the remaining carbons (with sp2 and sp1 character) attach in short chains of length 1 to 7. In sliding simulations including glycerol molecules, the surface atoms react readily to form a very smooth carbon surface containing OH-terminated groups. This agrees with our SIMS experiments. The simulations find that the OH atoms are mostly bound to surface sp1 atoms leading to very flexible elastic response to sliding. Both simulations and experiments suggest that the origin of the superlubricity arises from the formation of this OH-terminated surface

  11. Adhesion improvement of hydrogenated diamond-like carbon thin films by pre-deposition plasma treatment of rubber substrate

    NARCIS (Netherlands)

    Bui, X.L.; Pei, Y.T.; Mulder, E.D.G.; Hosson, J.Th.M. De

    2009-01-01

    For reduction of friction and enhancement of wear resistance of dynamic rubber seals, thin films of hydrogenated diamond-like carbon (DLC) have been deposited on hydrogenated nitrile butadiene rubber (HNBR) via magnetron-enhanced plasma chemical vapor deposition (ME-PCVD). Pre-deposition plasma trea

  12. Influence of load on the dry frictional performance of alkyl acrylate copolymer elastomers coated with diamond-like carbon films

    NARCIS (Netherlands)

    Martinez, D. Martinez; Nohava, Jiri; De Hosson, J. Th. M.

    2015-01-01

    In this work, the influence of applied load on the frictional behavior of alkyl acrylate copolymer elastomers coated with diamond- like carbon films is studied at dry conditions. The performance of two coatings with very different microstructure (patched vs. continuous film) is compared with the unc

  13. Preparation and investigation of diamond-like carbon nanocomposite thin films for nanophotonics

    Science.gov (United States)

    Panosyan, Zh.; Gharibyan, A.; Sargsyan, A.; Panosyan, H.; Hayrapetyan, D.; Yengibaryan, Y.

    2010-08-01

    Flexible Plasma Enhanced Chemical Vapor Deposition (PECVD) technology of Diamond Like Carbon (DLC) thin film preparation on the surface of Si and organic glasses has been elaborated. Modification of PECVD equipment has been implemented by integrating ion and magnetron sources. In this paper toluene (C7H8) has been used as a nanocmposite film forming hydrocarbon which decomposition yields to the multi component plasma in vacuum chamber. Nitrogen has been used as a dopand. Investigation of plasma composition influence to the optical and mechanical properties of DLC films has been observed. The presence of sp3 and sp2 hybridization states have been proven by Raman spectroscopy and their ratios have been estimated with the help of ID, IG characteristic lines for different technological conditions. High precision refractive index and thickness measurements of DLC films have been implemented by means of laser ellipsometer. Refractive indices of prepared films have been varied in the region 1.5-3.1 and thicknesses have been varied in the region 50-250 nm. Extraordinary change in refractive index has been explained with the help of formation of differently sized sp2 carbon based clusters in the sp3 matrix. Different types of carbon and hydrogen bonds have been observed in the obtained structures by means of FTIR. Obvious prospectives of DLC nanocomposite film as a promissing nanophotonic material has been discussed.

  14. Effect of source gas chemistry on tribological performance of diamond-like carbon films.

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, A.; Eryilmaz, O. L.; Fenske, G. R.; Nilufer, I. B.

    1999-08-23

    In this study, we investigated the effects of various source gases (i. e., methane, ethane, ethylene, acetylene and methane + hydrogen) on friction and wear performance of diamond-like carbon (DLC) films. Specifically, we described the anomalous nature and fundamental friction and wear mechanisms of DLC films derived from gas discharge plasmas with very low to very high hydrogen content. The films were deposited on steel substrates by a plasma enhanced chemical vapor deposition process at room temperature and the tribological tests were performed in dry nitrogen. The results of tribological tests revealed a close correlation between the friction and wear coefficients of the DLC films and the source gas chemistry. Specifically, films grown in source gases with higher hydrogen-to-carbon ratios had much lower friction coefficients and wear rates than the films derived from source gases with lower hydrogen-to-carbon ratios. The lowest friction coefficient (0.002) was achieved with a film derived from 25% methane--75% hydrogen while the films derived from acetylene had a coefficient of 0.15. Similar correlations were observed on wear rates. Specifically, the films derived from hydrogen rich plasmas had the least wear while the films derived from pure acetylene suffered the highest wear. We used a combination of scanning and transmission electron microscopy and Raman spectroscopy to characterize the structural chemistry of the resultant DLC films.

  15. Electron transport in W-containing amorphous carbon-silicon diamond-like nanocomposites

    International Nuclear Information System (INIS)

    The electron transport in amorphous hydrogenated carbon-silicon diamond-like nanocomposite films containing tungsten over the concentration range 12-40 at.% was studied in the temperature range 80-400 K. The films were deposited onto polycrystalline substrates, placed on the RF-biased substrate holder, by the combination of two methods: PECVD of siloxane vapours in the stimulated dc discharge and dc magnetron sputtering of tungsten target. The experimental dependences of the conductivity on the temperature are well fitted by the power-law dependences over the entire temperature range. The results obtained are discussed in terms of the model of inelastic tunnelling of the electrons in amorphous dielectrics. The average number of localized states (n) in the conducting channels between metal clusters calculated in the framework of this model is characterized by the non-monotonic dependence on the tungsten concentration in the films. The qualitative explanation of the results on the basis of host carbon-silicon matrix structural modifications is proposed. The evolution of the carbon-silicon matrix microstructure by the increase in the tungsten concentration is confirmed by the Raman spectroscopy data

  16. Molecular dynamics simulation of the deposition process of hydrogenated diamond-like carbon (DLC) films

    Institute of Scientific and Technical Information of China (English)

    ZHANG YuJun; DONG GuangNeng; MAO JunHong; XIE YouBai

    2008-01-01

    The deposition process of hydrogenated diamond-like carbon (DLC) film greatly affects its frictional properties. In this study, CH3 radicals are selected as source species to deposit hydrogenated DLC films for molecular dynamics simulation. The growth and structural properties of hydrogenated DLC films are investigated and elucidated in detail. By comparison and statistical analysis, the authors find that the ratio of carbon to hydrogen in the films generally shows a monotonously increasing trend with the increase of impact energy. Carbon atoms are more reactive during deposition and more liable to bond with substrate atoms than hydrogen atoms. In addition, there exists a peak value of the number of hydrogen atoms deposited in hydrogenated DLC films. The trends of the variation are opposite on the two sides of this peak point, and itbecomes stable when impact energy is greater than 80 eV. The average relative density also indicates a rising trend along with the increment of impact energy, while it does not reach the saturation value until impact energy comes to 50 eV. The hydrogen content in source species is a key factor to determine the hydrogen content in hydrogenated DLC films. When the hydrogen content in source species is high, the hydrogen content in hydrogenated DLC films is accordingly high.

  17. Treating orthopedic prosthesis with diamond-like carbon: minimizing debris in Ti6Al4V.

    Science.gov (United States)

    Oliveira, Luciane Y S; Kuromoto, Neide K; Siqueira, Carlos J M

    2014-10-01

    Prostheses are subject to various forms of failing mechanisms, including wear from ordinary patient motion. Superficial treatments can improve tribological properties of the contact pair, minimizing wear and increasing prostheses lifetime. One possibility is the diamond-like carbon (DLC) coating, where Carbon is deposited with variable ratio of sp(2)/sp(3) structures, leading to an increase in surface hardness. So in this research Ti6Al4V samples were coated with DLC using sputtering process to evaluate the debris release. The Ti6Al4V and Ti6Al4V plus DLC coating surfaces were analyzed using Raman spectroscopy and instrumented indentation (hardness). The wear behavior was tested using a reciprocating linear tribometer. The wear rate was smaller in the coated samples, producing less debris than the untreated Ti6Al4V alloy. Debris morphology was also evaluated, using scanning electronic microscopy, and it was observed that debris size from the coated samples were bigger than those observed from the uncoated Ti6Al4V alloy, above the size that generally triggers biological response from the host. PMID:24948374

  18. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Y.S., E-mail: yshzou75@gmail.com [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094 (China); Wu, Y.F.; Yang, H.; Cang, K. [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094 (China); Song, G.H. [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang, Liaoning, 110178 (China); Li, Z.X.; Zhou, K. [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094 (China)

    2011-12-01

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp{sup 3} carbon content and mechanical properties of the deposited DLC films. A maximum sp{sup 3} content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  19. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    International Nuclear Information System (INIS)

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp3 carbon content and mechanical properties of the deposited DLC films. A maximum sp3 content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  20. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    Science.gov (United States)

    Zou, Y. S.; Wu, Y. F.; Yang, H.; Cang, K.; Song, G. H.; Li, Z. X.; Zhou, K.

    2011-12-01

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp3 carbon content and mechanical properties of the deposited DLC films. A maximum sp3 content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  1. Tribological behaviors of hydrogenated diamond-like carbon films in different testing environments

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-min; LI Hong-xuan; XU Tao; ZHOU Hui-di; LIU Hui-wen

    2004-01-01

    Hydrogenated diamond-like carbon (DLC) films were deposited on Si substrate using plasma enhanced chemical vapor deposition(PECVD) technique with CH4 plus H2 as the feedstock. The tribological properties of the hydrogenated DLC films were measured on a ball-on-disk tribometer in different testing environments (humid air,dry air, dry O2, dry Ar and dry N2 ) sliding against Si3 N4 balls. The friction surfaces of the films and Si3 N4 balls were observed on a scanning electron microscope (SEM) and investigated by X-ray photoelectron spectroscopy (XPS). The results show that the tribological properties of the hydrogenated DLC films are strongly dependent on the testing environments. In dry Ar and dry N2 environments, the hydrogenated DLC films provide a superlow friction coefficient of about 0. 008 -0.01 and excellent wear resistance (wear life of above 56 km). In dry air and dry O2, the friction coefficient is increased to 0. 025 - 0.04 and the wear life is decreased to about 30 km. When sliding in moist air, the friction coefficient of the films is further increased to 0. 08 and the wear life is decreased to 10. 4 km. SEM and XPS analyses show that the tribological behaviors appear to rely on the transferred carbon-rich layer processes on the Si3 N4 balls and on the friction-induced oxidation of the films controlled by the nature of the testing environments.

  2. Surface characterization of diamond-like carbon for ultracold neutron storage

    Science.gov (United States)

    Atchison, F.; Bergmaier, A.; Daum, M.; Döbeli, M.; Dollinger, G.; Fierlinger, P.; Foelske, A.; Henneck, R.; Heule, S.; Kasprzak, M.; Kirch, K.; Knecht, A.; Kuźniak, M.; Pichlmaier, A.; Schelldorfer, R.; Zsigmond, G.

    2008-03-01

    We report the characterization of diamond-like carbon (DLC) surfaces to be used for the storage of ultracold neutrons (UCN). The samples investigated were 100-300-nm-thick tetragonal amorphous carbon (ta-C) coatings produced by vacuum-arc technology on thin foils (0.1-0.2 mm aluminum, stainless steel, PET). The diamond sp 3 fraction was determined by X-ray photoelectron spectroscopy (XPS) to be in the range 45-65%. Secondary-ion mass spectroscopy (SIMS) and elastic recoil detection analysis (ERDA) yielded consistent results for the hydrogen contribution (about 1×10 16 cm -2 within the top 20 nm), strongly concentrated within a surface layer of 1 nm thickness. The boron contamination was found to be around 50 at. ppm. The fractional hole area of the coatings is on a level of about 1×10 -4. Temperature cycling of mechanically pre-stressed samples between 77 and 380 K revealed no detrimental effect.

  3. Graphite-like and Diamond-like Carbon Coatings with Exceptional Tribological Properties

    Institute of Scientific and Technical Information of China (English)

    M.Jarratt; S.K.Field; S.Yang; D.G.Teer

    2004-01-01

    Two hard, carbon-based solid lubricant coatings, Graphit-iCTM and Dymon-iCTM, have been developed that offer considerable benefits for industry. Both of these new coatings have a high tribological load-bearing capacity, exceptional wear resistance and very low friction, even in dry or lubricant-starved contact. This is in contrast to many commercial diamond-like carbon, DLC coatings, which tend to be highly stressed and therefore brittle, making them unsuitable for high load bearing industrial applications. The development of the new solid lubricant coatings is described, and details of their tribological performance in dry, water and oil-lubricated environments are given. The structure of the coatings has been investigated and related to the tribological properties, and the mechanism for the low friction and wea rrates is discussed. The coatings have been used to successfully improve the lifetime and efficiency of many highly loaded mechanical parts, including automotive fuel injection components, gears, bearings, tappets (cam followers), gudgeon (wrist) pins, etc. They also offer benefits for tooling and are widely used in forming or machining of non-ferrous alloys, and extensively on dies and moulds. Other industrial application areas include electrical devices that require either high conductivity or insulation, optical devices requiring abrasion resistance and surgical tools and implants.

  4. Graphite-like and Diamond-like Carbon Coatings with Exceptional Tribological Properties

    Institute of Scientific and Technical Information of China (English)

    M. Jarratt; S. K. Field; S. Yang; D.G. Teer

    2004-01-01

    Two hard, carbon-based solid lubricant coatings, Graphit-iCTM and Dymon-iCTM, have been developed that offer considerable benefits for industry. Both of these new coatings have a high tribological load-bearing capacity,exceptional wear resistance and very low friction, even in dry or lubricant-starved contact. This is in contrast to many commercial diamond-like carbon, DLC coatings, which tend to be highly stressed and therefore brittle, making them unsuitable for high load bearing industrial applications. The development of the new solid lubricant coatings is described,and details of their tribological performance in dry, water and oil-lubricated environments are given. The structure of the coatings has been investigated and related to the tribological properties, and the mechanism for the low friction and wear rates is discussed. The coatings have been used to successfully improve the lifetime and efficiency of many highly loaded mechanical parts, including automotive fuel injection components, gears, bearings, tappets (cam followers), gudgeon (wrist)pins, etc. They also offer benefits for tooling and are widely used in forming or machining of non-ferrous alloys, and extensively on dies and moulds. Other industrial application areas include electrical devices that require either high conductivity or insulation, optical devices requiring abrasion resistance and surgical tools and implants.

  5. Target-plane deposition of diamond-like carbon in pulsed laser ablation of graphite

    Energy Technology Data Exchange (ETDEWEB)

    Yap, S.S. [Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia); Tou, T.Y. [Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia)], E-mail: tytou@mmu.edu.my

    2007-10-15

    In pulsed Nd:YAG laser ablation of highly oriented pyrolytic graphite (HOPG) at 10{sup -6} Torr, diamond-like carbon (DLC) are deposited at laser wavelengths of 1064, 532, and 355 nm on substrates placed in the target-plane. These target-plane samples are found to contain varying sp{sup 3} content and composed of nanostructures of 40-200 nm in size depending on the laser wavelength and laser fluence. The material and origin of sp{sup 3} in the target-plane samples is closely correlated to that in the laser-modified HOPG surface layer, and hardly from the backward deposition of ablated carbon plume. The surface morphology of the target-plane samples shows the columnar growth and with a tendency for agglomeration between nanograins, in particular for long laser wavelength at 1064 nm. It is also proposed that DLC formation mechanism at the laser-ablated HOPG is possibly via the laser-induced subsurface melting and resolidification.

  6. Conditions for forming composite carbon nanotube-diamond like carbon material that retain the good properties of both materials

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Wei, E-mail: wei.ren@helsinki.fi; Avchaciov, Konstantin; Nordlund, Kai [Department of Physics, University of Helsinki, P.O. Box 43, FIN-00014 Helsinki (Finland); Iyer, Ajai; Koskinen, Jari [Department of Materials Science and Engineering, School of Chemical Technology, Aalto University, P.O. Box 16200, 00076 Espoo (Finland); Kaskela, Antti; Kauppinen, Esko I. [NanoMaterials Group, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, 00076 Aalto (Finland)

    2015-11-21

    Carbon nanotubes are of wide interest due to their excellent properties such as tensile strength and electrical and thermal conductivity, but are not, when placed alone on a substrate, well resistant to mechanical wear. Diamond-like carbon (DLC), on the other hand, is widely used in applications due to its very good wear resistance. Combining the two materials could provide a very durable pure carbon nanomaterial enabling to benefit from the best properties of both carbon allotropes. However, the synthesis of high-quality diamond-like carbon uses energetic plasmas, which can damage the nanotubes. From previous works it is neither clear whether the quality of the tubes remains good after DLC deposition, nor whether the DLC above the tubes retains the high sp{sup 3} bonding fraction. In this work, we use experiments and classical molecular dynamics simulations to study the mechanisms of DLC formation on various carbon nanotube compositions. The results show that high-sp{sup 3}-content DLC can be formed provided the deposition conditions allow for sidewards pressure to form from a substrate close beneath the tubes. Under optimal DLC formation energies of around 40–70 eV, the top two nanotube atom layers are fully destroyed by the plasma deposition, but layers below this can retain their structural integrity.

  7. Conditions for forming composite carbon nanotube-diamond like carbon material that retain the good properties of both materials

    International Nuclear Information System (INIS)

    Carbon nanotubes are of wide interest due to their excellent properties such as tensile strength and electrical and thermal conductivity, but are not, when placed alone on a substrate, well resistant to mechanical wear. Diamond-like carbon (DLC), on the other hand, is widely used in applications due to its very good wear resistance. Combining the two materials could provide a very durable pure carbon nanomaterial enabling to benefit from the best properties of both carbon allotropes. However, the synthesis of high-quality diamond-like carbon uses energetic plasmas, which can damage the nanotubes. From previous works it is neither clear whether the quality of the tubes remains good after DLC deposition, nor whether the DLC above the tubes retains the high sp3 bonding fraction. In this work, we use experiments and classical molecular dynamics simulations to study the mechanisms of DLC formation on various carbon nanotube compositions. The results show that high-sp3-content DLC can be formed provided the deposition conditions allow for sidewards pressure to form from a substrate close beneath the tubes. Under optimal DLC formation energies of around 40–70 eV, the top two nanotube atom layers are fully destroyed by the plasma deposition, but layers below this can retain their structural integrity

  8. Diamond-Like Carbon Coatings as Encapsulants for Photovoltaic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Pern, F. J.; Panosyan, Zh.; Gippius, A. A.; Kontsevoy, J. A.; Touryan, K.; Voskanyan, S.; Yengibaryan, Y.

    2005-02-01

    High-quality single-layer and bilayer diamond-like carbon (DLC) thin films are fabricated by two technologies, namely, ion-assisted plasma-enhanced deposition (IAPED) and electron cyclotron resonance (ECR) deposition. Deposition on various substrates, such as sapphires and solar cells, has been performed at low substrate temperatures (50 {approx} 80 C). The two deposition technologies allow good control over the growth conditions to produce DLC films with desired optical properties, thickness, and energy bandgap. The bilayer-structured DLC can be fabricated by using IAPED for the bottom layer followed by ECR for the top layer, or just by IAPED for both layers with different compositions. The DLC films have shown good spatial uniformity, density, microhardness, and adhesion strength. They exhibit excellent stability against attack by strong acids, prolonged damp-heat exposure at 85 C and 85% relative humidity, mechanical scratch, ultrasonication, and irradiation by ultraviolet (UV), protons, and electrons. When deposited on crystalline Si and GaAs solar cells in single-layer and/or bilayer structure, the DLC films not only serve as antireflection coating and protective encapsulant, but also improve the cell efficiencies.

  9. Plasma post-processing of diamond-like carbon nano-coated long-period gratings

    Science.gov (United States)

    Śmietana, Mateusz; Krysiński, Adrian; Bock, Wojtek J.; Mikulic, Predrag

    2013-09-01

    This work presents an application of reactive ion etching (RIE) for effective tuning of spectral response and the refractive-index (RI) sensitivity of diamond-like carbon (DLC) nano-coated long-period gratings (LPGs). The technique allows for an efficient and well controlled etching of the DLC by means of O2 and CF4 plasma. The effect of DLC nanocoating etching on spectral properties of the LPGs is discussed. We correlated the decrease in DLC thickness with the shift of the LPG resonance wavelength. The thinning of the overlay effectively changes the distribution of the cladding modes and thus it also has an impact on the device's RI sensitivity. The advantage of this approach is a capability for post-processing of the nano-coated structures with a good precision (etching rate from 4.6 to 8.1 nm/min for O2 plasma), cleaning the samples and their re-coating according to requested needs.

  10. High rate PLD of diamond-like-carbon utilizing high repetition rate visible lasers

    Energy Technology Data Exchange (ETDEWEB)

    McLean, W. II; Fehring, E.J.; Dragon, E.P.; Warner, B.E.

    1994-09-15

    Pulsed Laser Deposition (PLD) has been shown to be an effective method for producing a wide variety of thin films of high-value-added materials. The high average powers and high pulse repetition frequencies of lasers under development at LLNL make it possible to scale-up PLD processes that have been demonstrated in small systems in a number of university, government, and private laboratories to industrially meaningful, economically feasible technologies. A copper vapor laser system at LLNL has been utilized to demonstrate high rate PLD of high quality diamond-like-carbon (DLC) from graphite targets. The deposition rates for PLD obtained with a 100 W laser were {approx} 2000 {mu}m{center_dot}cm{sup 2}/h, or roughly 100 times larger than those reported by chemical vapor deposition (CVD) or physical vapor deposition (PVD) methods. Good adhesion of thin (up to 2 pm) films has been achieved on a small number of substrates that include SiO{sub 2} and single crystal Si. Present results indicate that the best quality DLC films can be produced at optimum rates at power levels and wavelengths compatible with fiber optic delivery systems. If this is also true of other desirable coating systems, this PLD technology could become an extremely attractive industrial tool for high value added coatings.

  11. Annealing Effects on Structure and Optical Properties of Diamond-Like Carbon Films Containing Silver.

    Science.gov (United States)

    Meškinis, Šarūnas; Čiegis, Arvydas; Vasiliauskas, Andrius; Šlapikas, Kęstutis; Gudaitis, Rimantas; Yaremchuk, Iryna; Fitio, Volodymyr; Bobitski, Yaroslav; Tamulevičius, Sigitas

    2016-12-01

    In the present study, diamond-like carbon films with embedded Ag nanoparticles (DLC:Ag) were deposited by reactive magnetron sputtering. Structure of the films was investigated by Raman scattering spectroscopy. Atomic force microscopy was used to define thickness of DLC:Ag films as well as to study the surface morphology and size distribution of Ag nanoparticles. Optical absorbance and reflectance spectra of the films were studied in the 180-1100-nm range. Air annealing effects on structure and optical properties of the DLC:Ag were investigated. Annealing temperatures were varied in the 180-400 °C range. Changes of size and shape of the Ag nanoclusters took place due to agglomeration. It was found that air annealing of DLC:Ag films can result in graphitization following destruction of the DLC matrix. Additional activation of surface-enhanced Raman scattering (SERS) effect in DLC:Ag films can be achieved by properly selecting annealing conditions. Annealing resulted in blueshift as well as significant narrowing of the plasmonic absorbance and reflectance peaks. Moreover, quadrupole surface plasmon resonance peaks appeared. Modeling of absorption spectra of the nanoclusters depending on the shape and surrounding media has been carried out. PMID:26979724

  12. Optical and mechanical properties of diamond like carbon films deposited by microwave ECR plasma CVD

    Indian Academy of Sciences (India)

    S B Singh; M Pandey; N Chand; A Biswas; D Bhattacharya; S Dash; A K Tyagi; R M Dey; S K Kulkarni; D S Patil

    2008-10-01

    Diamond like carbon (DLC) films were deposited on Si (111) substrates by microwave electron cyclotron resonance (ECR) plasma chemical vapour deposition (CVD) process using plasma of argon and methane gases. During deposition, a d.c. self-bias was applied to the substrates by application of 13.56 MHz rf power. DLC films deposited at three different bias voltages (–60 V, –100 V and –150 V) were characterized by FTIR, Raman spectroscopy and spectroscopic ellipsometry to study the variation in the bonding and optical properties of the deposited coatings with process parameters. The mechanical properties such as hardness and elastic modulus were measured by load depth sensing indentation technique. The DLC film deposited at –100 V bias exhibit high hardness (∼ 19 GPa), high elastic modulus (∼ 160 GPa) and high refractive index (∼ 2.16–2.26) as compared to films deposited at –60 V and –150 V substrate bias. This study clearly shows the significance of substrate bias in controlling the optical and mechanical properties of DLC films.

  13. Deodorisation effect of diamond-like carbon/titanium dioxide multilayer thin films deposited onto polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Ozeki, K., E-mail: ozeki@mx.ibaraki.ac.jp [Department of Mechanical Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan); Frontier Research Center for Applied Atomic Sciences, 162-1 Shirakata, Toukai, Ibaraki 319-1106 (Japan); Hirakuri, K.K. [Applied Systems Engineering, Graduate School of Science and Engineering, Tokyo Denki University, Ishizaka, Hatoyama, Hiki, Saitama 350-0394 (Japan); Masuzawa, T. [Department of Mechanical Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan)

    2011-04-15

    Many types of plastic containers have been used for the storage of food. In the present study, diamond-like carbon (DLC)/titanium oxide (TiO{sub 2}) multilayer thin films were deposited on polypropylene (PP) to prevent flavour retention and to remove flavour in plastic containers. For the flavour removal test, two types of multilayer films were prepared, DLC/TiO{sub 2} films and DLC/TiO{sub 2}/DLC films. The residual gas concentration of acetaldehyde, ethylene, and turmeric compounds in bottle including the DLC/TiO{sub 2}-coated and the DLC/TiO{sub 2}/DLC-coated PP plates were measured after UV radiation, and the amount of adsorbed compounds to the plates was determined. The percentages of residual gas for acetaldehyde, ethylene, and turmeric with the DLC/TiO{sub 2} coated plates were 0.8%, 65.2% and 75.0% after 40 h of UV radiation, respectively. For the DLC/TiO{sub 2}/DLC film, the percentages of residual gas for acetaldehyde, ethylene and turmeric decreased to 34.9%, 76.0% and 85.3% after 40 h of UV radiation, respectively. The DLC/TiO{sub 2}/DLC film had a photocatalytic effect even though the TiO{sub 2} film was covered with the DLC film.

  14. Frictional and Optical Properties of Diamond-Like-Carbon Coatings on Polycarbonate

    International Nuclear Information System (INIS)

    In this work, diamond-like-carbon (DLC) films were deposited onto polycarbonate (PC) substrates by radio-frequency plasma-enhanced chemical vapor deposition (RF PECVD), and silicon films were prepared between DLC and PC substrates by magnetron sputtering deposition so as to improve the adhesion of the DLC films. The deposited films were investigated by means of field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Subsequently, the following frictional and optical properties of the films were measured: the friction coefficient by using a ball-on-disk tribometer, the scratch hardness by using a nano-indenter, the optical transmittance by using a UV/visible spectrometer. The effects of incident power upon the frictional and optical properties of the films were investigated. Films deposited at low incident powers showed large optical gaps, which decreased with increasing incident power. The optical properties of DLC films correlated to the sp2 content of the coatings. High anti-scratch properties were obtained at higher values of incident power. The anti-scratch properties of DLC films correlated to the sp3 content of the coatings

  15. Modifying surface properties of diamond-like carbon films via nanotexturing

    Energy Technology Data Exchange (ETDEWEB)

    Corbella, C; Portal-Marco, S; Rubio-Roy, M; Bertran, E; Andujar, J L [FEMAN Group, IN2UB, Departament de Fisica Aplicada i Optica, Universitat de Barcelona, c/ Marti i Franques 1, 08028 Barcelona (Spain); Oncins, G [Serveis CientIfico-Tecnics, Universitat de Barcelona, c/ Marti i Franques s/n, 08028 Barcelona (Spain); Vallve, M A; Ignes-Mullol, J, E-mail: corberoc@hotmail.com [SOC and SAM Group, IN2UB, Departament de Quimica Fisica, Universitat de Barcelona, c/ Marti i Franques 1, 08028 Barcelona (Spain)

    2011-10-05

    Diamond-like amorphous carbon (DLC) films have been grown by pulsed-dc plasma-enhanced chemical vapour deposition on silicon wafers, which were previously patterned by means of colloidal lithography. The substrate conditioning comprised two steps: first, deposition of a self-assembled monolayer of silica sub-micrometre spheres ({approx}300 nm) on monocrystalline silicon ({approx}5 cm{sup 2}) by Langmuir-Blodgett technique, which acted as lithography template; second, substrate patterning via ion beam etching (argon) of the colloid samples (550 eV) at different incidence angles. The plasma deposition of a DLC thin film on the nanotextured substrates resulted in hard coatings with distinctly different surface properties compared with planar DLC. Also, in-plane anisotropy was generated depending on the etching angle. The samples were morphologically characterized by scanning electron microscopy and atomic force microscopy. The anisotropy introduced by the texture was evidenced in the surface properties, as shown by the directional dependences of wettability (water contact angle) and friction coefficient. The latter was measured using a nanotribometer and a lateral force microscope. These two techniques showed how the nanopatterns influenced the tribological properties at different scales of load and contact area. This fabrication technique finds applications in the industry of microelectromechanical systems, anisotropic tribological coatings, nanoimprint lithography, microfluidics, photonic crystals, and patterned surfaces for biomedicine.

  16. Segment-Structured Diamond-Like Carbon Coatings on Polymer Catheter

    Science.gov (United States)

    Nakagawa, Taku; Ohishi, Ryusuke; Ohtake, Naoto; Takai, Osamu; Tsutsui, Nobumasa; Tsutsui, Yasuhiro; Muraki, Yasuhiro; Ogura, Jyunpei

    Diamond-like carbon (DLC) has remarkable mechanical and tribological properties. Besides those mechanical properties, it has been clarified that DLC shows high biocompatibility in recent years. DLC coating can give high strength, abrasion resistance, and biocompatibility for surface of substrates. Hence DLC is a candidate for the coating material for medical devices such as artificial organ, joint, catheter, etc. The objective of this study is to develop safety protection films for implantable medical polymer devices utilizing segment-structured DLC (S-DLC) coatings. S-DLC and continuous-structured DLC were deposited on polyurethane and nylon sheet for balloon catheters. As a result, friction coefficient of DLC coated polyurethane sheet was approximately one-sixth of that of pristine polyurethane sheet, and S-DLC showed very low friction coefficient of μ=0.1-0.15. DLC coating can prevent polyurethane sheet from worn out. The puncture-resistance of nylon sheets increased 0.2MPa on average by DLC coatings regardless of the film structure. It was confirmed that DLC inhibits adsorption of blood coagulation factor. In conclusion, we succeed to verify that these DLC films can improve tribological property, abrasion-resistance, puncture-resistance, and anti-thrombogenicity of polymer catheters. Moreover, segment-structured DLC films exhibits high performance for protection of polymer material for polymer catheters.

  17. Tribological behavior of diamond-like carbon: effects of preparation conditions and annealing

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) films are characterized by, among other properties, very low friction coefficients, high wear resistance, and high corrosion resistance. Depending upon the testing environment, the coefficient of friction can be as low as 0.01. As-deposited films are wear resistant in vacuum as well as in atmospheric ambient. This paper will discuss the general tribological behavior, in different environments, of DLC films deposited under a variety of conditions, and proposed mechanisms explaining the very low friction coefficients observed. The specific properties of DLC films deposited from acetylene by r.f. plasma-enhanced chemical vapor deposition will then be presented. The films were deposited at substrate temperatures between 100degC and 250degC, at various substrate biases. The films were annealed in vacuum at temperatures up to 590degC. The tribological properties of the as-deposited as well as annealed DLC films will be presented as a function of the deposition parameters. The observed behavior will be discussed and related to other physical properties of the films. (orig.)

  18. Modifying surface properties of diamond-like carbon films via nanotexturing

    Science.gov (United States)

    Corbella, C.; Portal-Marco, S.; Rubio-Roy, M.; Bertran, E.; Oncins, G.; Vallvé, M. A.; Ignés-Mullol, J.; Andújar, J. L.

    2011-10-01

    Diamond-like amorphous carbon (DLC) films have been grown by pulsed-dc plasma-enhanced chemical vapour deposition on silicon wafers, which were previously patterned by means of colloidal lithography. The substrate conditioning comprised two steps: first, deposition of a self-assembled monolayer of silica sub-micrometre spheres (~300 nm) on monocrystalline silicon (~5 cm2) by Langmuir-Blodgett technique, which acted as lithography template; second, substrate patterning via ion beam etching (argon) of the colloid samples (550 eV) at different incidence angles. The plasma deposition of a DLC thin film on the nanotextured substrates resulted in hard coatings with distinctly different surface properties compared with planar DLC. Also, in-plane anisotropy was generated depending on the etching angle. The samples were morphologically characterized by scanning electron microscopy and atomic force microscopy. The anisotropy introduced by the texture was evidenced in the surface properties, as shown by the directional dependences of wettability (water contact angle) and friction coefficient. The latter was measured using a nanotribometer and a lateral force microscope. These two techniques showed how the nanopatterns influenced the tribological properties at different scales of load and contact area. This fabrication technique finds applications in the industry of microelectromechanical systems, anisotropic tribological coatings, nanoimprint lithography, microfluidics, photonic crystals, and patterned surfaces for biomedicine.

  19. Fatigue Properties and Fracture Mechanism of Steel Coated with Diamond-Like Carbon Films

    Science.gov (United States)

    Akebono, Hiroyuki; Kato, Masahiko; Sugeta, Atsushi

    Diamond-like carbon (DLC) films have attracted much attention in many industrial fields because of their excellent tribological properties, high hardness, chemical inertness and biocompatibility. In order to examine the fatigue properties and to clear the fracture mechanism of DLC coated materials, AISI4140 steel coated with DLC films by using unbalanced magnetron sputtering method was prepared and two types of fatigue test were carried out by using a tension and compression testing machine with stress ratio -1 and a bending testing machine with stress ratio -1 with a focused on the fatigue crack behavior in detail. The fracture origin changed from the slip deformation to micro defects at surface whose size didn't affect the fatigue crack initiation behavior in the case of Virgin series because the hard coating like DLC films make the defect sensitivity of coated material higher. However, DLC series indicated higher fatigue strengths in finite life region and fatigue limit compared with Virgin series. From the continuously observation by using a plastic replicas technique, it is clear that there are no noticeable differences on fatigue crack propagation rate between the Virgin and DLC series, however the fatigue crack initiation of DLC series was delayed significantly by existence of DLC films compared with Virgin series.

  20. The nano-scratch behaviour of different diamond-like carbon film-substrate systems

    Energy Technology Data Exchange (ETDEWEB)

    Huang Liye [State-Key Laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an, 710049 (China); Lu Jian [LASMIS, Universite de Technologie de Troyes, 10010 Troyes (France); Xu Kewei [State-Key Laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an, 710049 (China)

    2004-08-07

    The nano-scratch behaviour of diamond-like carbon films on a Ti alloy and Si substrate was evaluated. For both samples, three processes-fully elastic recovery, plastic deformation, and delamination and pulling-off of the films, occur successively with increasing load during scratching. The loads (Lc{sub L}) corresponding to the peeling-off of the films during the up-loading were 75 and 70 mN for Ti alloy and Si. However, the films on Si were delaminated during unloading, and the relevant load (Lc{sub U}) was only 45 mN. This probably originates from the distribution status of the plastic deformation both in the films and the substrates. Therefore, the nano-scratch test can be applied not only to obtain the cracking resistance (Lc{sub L}) characterizing the cohesion strength of films during up-loading but also to determine the delamination resistance (Lc{sub U}) related to the adhesion strength of the film-substrate during unloading.

  1. Modifying surface properties of diamond-like carbon films via nanotexturing

    International Nuclear Information System (INIS)

    Diamond-like amorphous carbon (DLC) films have been grown by pulsed-dc plasma-enhanced chemical vapour deposition on silicon wafers, which were previously patterned by means of colloidal lithography. The substrate conditioning comprised two steps: first, deposition of a self-assembled monolayer of silica sub-micrometre spheres (∼300 nm) on monocrystalline silicon (∼5 cm2) by Langmuir-Blodgett technique, which acted as lithography template; second, substrate patterning via ion beam etching (argon) of the colloid samples (550 eV) at different incidence angles. The plasma deposition of a DLC thin film on the nanotextured substrates resulted in hard coatings with distinctly different surface properties compared with planar DLC. Also, in-plane anisotropy was generated depending on the etching angle. The samples were morphologically characterized by scanning electron microscopy and atomic force microscopy. The anisotropy introduced by the texture was evidenced in the surface properties, as shown by the directional dependences of wettability (water contact angle) and friction coefficient. The latter was measured using a nanotribometer and a lateral force microscope. These two techniques showed how the nanopatterns influenced the tribological properties at different scales of load and contact area. This fabrication technique finds applications in the industry of microelectromechanical systems, anisotropic tribological coatings, nanoimprint lithography, microfluidics, photonic crystals, and patterned surfaces for biomedicine.

  2. Gas barrier properties of diamond-like carbon films coated on PTFE

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) films were deposited on polytetrafluoroethylene (PTFE) using radio frequency (RF) plasma-enhanced chemical vapour deposition (PE-CVD). Before the DLC coating, the PTFE substrate was modified with a N2 plasma pre-treatment to enhance the adhesive strength of the DLC to the substrate. The influences of the N2 plasma pre-treatment and process pressure on the gas permeation properties of these DLC-coated PTFE samples were investigated. In the Raman spectra, the G peak position shifted to a lower wave number with increasing process pressure. With scanning electron microscopy (SEM), a network of microcracks was observed on the surface of the DLC film without N2 plasma pre-treatment. The density of these cracks decreased with increasing process pressure. In the film subjected to a N2 plasma pre-treatment, no cracks were observed at any process pressure. In the gas barrier test, the gas permeation decreased drastically with increasing film thickness and saturated at a thickness of 0.2 μm. The DLC-coated PTFE with the N2 plasma pre-treatment exhibited a greater reduction in gas permeation than did the samples without pre-treatment. For both sample types, gas permeation decreased with increasing process pressure.

  3. X-ray reflectivity study of bias graded diamond like carbon film synthesized by ECR plasma

    Indian Academy of Sciences (India)

    R M Dey; S K Deshpande; S B Singh; N Chand; D S Patil; S K Kulkarni

    2013-02-01

    Diamond like carbon (DLC) coatings were deposited on silicon substrates by microwave electron cyclotron resonance (ECR) plasma CVD process using plasma of Ar and CH4 gases under the influence of negative d.c. self bias generated on the substrates by application of RF (13.56 MHz) power. The negative bias voltage was varied from −60 V to −150 V during deposition of DLC films on Si substrate. Detailed X-ray reflectivity (XRR) study was carried out to find out film properties like surface roughness, thickness and density of the films as a function of variation of negative bias voltage. The study shows that the DLC films constituted of composite layer i.e. the upper sub surface layer followed by denser bottom layer representing the bulk of the film. The upper layer is relatively thinner as compared to the bottom layer. The XRR study was an attempt to substantiate the sub-plantation model for DLC film growth.

  4. Synthesis and Characteristics of Diamond-like Carbon Films Deposited on Quartz Substrate

    Institute of Scientific and Technical Information of China (English)

    黄卫东; 丁鼎; 詹如娟

    2004-01-01

    Diamond-like carbon (DLC) films are deposited on quartz substrate using pure CH4 in the surface wave plasma equipment. A direct current negative bias up to -90 V is applied to the substrate to investigate the bias effect on the film characteristics. Deposited films are characterized by Raman spectroscopy, infrared (IR) and ultraviolet-visible absorption techniques.There are two broad Raman peaks around 1340 cm-1 and 1600 cm-1 and the first one has a greater sp3 component with an increased bias. Infrared spectroscopy has three sp3 C-H modes at 2852 cm-1, 2926 cm- 1 and 2962 cm-1, respectively and also shows an intensity increase with the negative bias. Optical band gap is calculated from the ultraviolet-visible absorption spectroscopy and the increased values with negative bias and deposition time are obtained. After a thermal anneal at about 500 ℃ for an hour to the film deposited under the bias of-90 V, we get an almost unchanged Raman spectrum and a peak intensity-reduced IR signal, which indicates a reduced H-content in the film. Meanwhile the optical band gap changed from 0.85 eV to 1.5 eV.

  5. Modification of diamond-like carbon films by nitrogen incorporation via plasma immersion ion implantation

    Science.gov (United States)

    Flege, S.; Hatada, R.; Hoefling, M.; Hanauer, A.; Abel, A.; Baba, K.; Ensinger, W.

    2015-12-01

    The addition of nitrogen to diamond-like carbon films affects properties such as the inner stress of the film, the conductivity, biocompatibility and wettability. The nitrogen content is limited, though, and the maximum concentration depends on the preparation method. Here, plasma immersion ion implantation was used for the deposition of the films, without the use of a separate plasma source, i.e. the plasma was generated by a high voltage applied to the samples. The plasma gas consisted of a mixture of C2H4 and N2, the substrates were silicon and glass. By changing the experimental parameters (high voltage, pulse length and repetition rate and gas flow ratio) layers with different N content were prepared. Additionally, some samples were prepared using a DC voltage. The nitrogen content and bonding was investigated with SIMS, AES, XPS, FTIR and Raman spectroscopy. Their influence on the electrical resistivity of the films was investigated. Depending on the preparation conditions different nitrogen contents were realized with maximum contents around 11 at.%. Those values were compared with the nitrogen concentration that can be achieved by implantation of nitrogen into a DLC film.

  6. Bacterial attachment and removal properties of silicon- and nitrogen-doped diamond-like carbon coatings.

    Science.gov (United States)

    Zhao, Qi; Su, Xueju; Wang, Su; Zhang, Xiaoling; Navabpour, Parnia; Teer, Dennis

    2009-01-01

    Si- and N-doped diamond-like carbon (DLC) coatings with various Si and N contents were deposited on glass slides using magnetron sputter ion-plating and plasma-enhanced chemical vapour deposition. Surface energy analysis of the DLC coatings revealed that with increasing Si content, the electron acceptor gamma(s)(+) value decreased while the electron donor gamma(s)(-) value increased. The antifouling property of DLC coatings was evaluated with the bacterium, Pseudomonas fluorescens, which is one of the most common microorganisms forming biofilms on the surface of heat exchangers in cooling water systems. P. fluorescens had a high value of the gamma(s)(-) component (69.78 mN m(-1)) and a low value of the gamma(s)(+) component (5.97 mN m(-1)), and would be negatively charged with the zeta potential of -16.1 mV. The experimental results showed that bacterial removal by a standardised washing procedure increased significantly with increasing electron donor gamma(s)(-) values and with decreasing electron acceptor gamma(s)(+) values of DLC coatings. The incorporation of 2%N into the Si-doped DLC coatings further significantly reduced bacterial attachment and significantly increased ease of removal. The best Si-N-doped DLC coatings reduced bacterial attachment by 58% and increased removal by 41%, compared with a silicone coating, Silastic T2. Bacterial adhesion strength on the DLC coatings is explained in terms of thermodynamic work of adhesion. PMID:19283517

  7. High-frequency, scaled graphene transistors on diamond-like carbon.

    Science.gov (United States)

    Wu, Yanqing; Lin, Yu-ming; Bol, Ageeth A; Jenkins, Keith A; Xia, Fengnian; Farmer, Damon B; Zhu, Yu; Avouris, Phaedon

    2011-04-01

    Owing to its high carrier mobility and saturation velocity, graphene has attracted enormous attention in recent years. In particular, high-performance graphene transistors for radio-frequency (r.f.) applications are of great interest. Synthesis of large-scale graphene sheets of high quality and at low cost has been demonstrated using chemical vapour deposition (CVD) methods. However, very few studies have been performed on the scaling behaviour of transistors made from CVD graphene for r.f. applications, which hold great potential for commercialization. Here we report the systematic study of top-gated CVD-graphene r.f. transistors with gate lengths scaled down to 40 nm, the shortest gate length demonstrated on graphene r.f. devices. The CVD graphene was grown on copper film and transferred to a wafer of diamond-like carbon. Cut-off frequencies as high as 155 GHz have been obtained for the 40-nm transistors, and the cut-off frequency was found to scale as 1/(gate length). Furthermore, we studied graphene r.f. transistors at cryogenic temperatures. Unlike conventional semiconductor devices where low-temperature performance is hampered by carrier freeze-out effects, the r.f. performance of our graphene devices exhibits little temperature dependence down to 4.3 K, providing a much larger operation window than is available for conventional devices. PMID:21475197

  8. Cavitation erosion resistance of diamond-like carbon coating on stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Feng; Jiang, Shuyun, E-mail: jiangshy@seu.edu.cn

    2014-02-15

    Two diamond-like carbon (DLC) coatings are prepared on stainless steel 304 by cathodic arc plasma deposition technology at different substrate bias voltages and arc currents (−200 V/80 A, labeled DLC-1, and −100 V/60 A, labeled DLC-2). Cavitation tests are performed by using a rotating-disk test rig to explore the cavitation erosion resistance of the DLC coating. The mass losses, surface morphologies, chemical compositions and the phase constituents of the specimens after cavitation tests are examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the DLC-2 coatings can elongate the incubation period of stainless steel, leading to an excellent cavitation erosion resistance as compared to the untreated stainless steel specimens. After duration of 100 h cavitation test, serious damaged surfaces and plenty of scratches can be observed on the surfaces of the stainless steel specimens, while only a few grooves and tiny pits are observed on the DLC-2 coatings. It is concluded that, decreasing micro defects and increasing adhesion can reduce the delamination of DLC coating, and the erosion continues in the stainless steel substrate after DLC coating failure, and the eroded surface of the substrate is subjected to the combined action from cavitation erosion and slurry erosion.

  9. Strength and Fracture Resistance of Amorphous Diamond-Like Carbon Films for MEMS

    Directory of Open Access Journals (Sweden)

    K. N. Jonnalagadda

    2009-01-01

    Full Text Available The mechanical strength and mixed mode I/II fracture toughness of hydrogen-free tetrahedral amorphous diamond-like carbon (ta-C films, grown by pulsed laser deposition, are discussed in connection to material flaws and its microstructure. The failure properties of ta-C were obtained from films with thicknesses 0.5–3 μm and specimen widths 10–20 μm. The smallest test samples with 10 μm gage section averaged a strength of 7.3 ± 1.2 GPa, while the strength of 20-μm specimens with thicknesses 0.5–3 μm varied between 2.2–5.7 GPa. The scaling of the mechanical strength with specimen thickness and dimensions was owed to deposition-induced surface flaws, and, only in the smallest specimens, RIE patterning generated specimen sidewall flaws. The mode I fracture toughness of ta-C films is KIc=4.4±0.4 MPam, while the results from mixed mode I/II fracture experiments with cracks arbitrarily oriented in the plane of the film compared very well with theoretical predictions.

  10. Effects of diamond-like carbon thin film in organic light emitting devices

    Energy Technology Data Exchange (ETDEWEB)

    Yap, Seong-Shan; Yong, Thian-Khok [Faculty of Engineering, Multimedia University, Cyberjaya, 63100 Selangor (Malaysia); Tou, Teck-Yong, E-mail: tytou@mmu.edu.m [Faculty of Engineering, Multimedia University, Cyberjaya, 63100 Selangor (Malaysia)

    2009-07-01

    Ultrathin diamond-like carbon (DLC) was deposited by pulsed Nd:YAG laserablation of graphite target on the indium tin oxide (ITO) surface that functioned as the buffered anode for single-layer organic light emitting devices (OLEDs). Deposited by 355 nm Nd:YAG laser, DLC films were characterized by the Raman spectroscopy and the bulk resistivity measurement. Insertion of DLC in the hole-transport ITO/DLC/TPD/Al device slightly increased the injection current density and reduced the turn-on voltage. But DLC insertion in the electron-transport ITO/DLC/Alq{sub 3}/Al device greatly decreased the injection current density and increased the turn-on voltage. For the ITO/DLC/(TPD + Alq{sub 3} + PVK)/Al device, that was doped with Alq{sub 3} and TPD, improved performance with a higher current density and brightness were consistently obtained. Possible mechanisms for the DLC effect in these single-layer devices were discussed.

  11. Friction force microscopy study of annealed diamond-like carbon film

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Won Seok; Joung, Yeun-Ho [School of Electrical Engineering, Hanbat National University, Daejeon 305-719 (Korea, Republic of); Heo, Jinhee [Materials Safety Evaluation Group, Korea Institute of Materials Science, Changwon 641-831 (Korea, Republic of); Hong, Byungyou, E-mail: byhong@skku.edu [School of Information and Communication Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2012-10-15

    In this paper we introduce mechanical and structural characteristics of diamond-like carbon (DLC) films which were prepared on silicon substrates by radio frequency (RF) plasma enhanced chemical vapor deposition (PECVD) method using methane (CH{sub 4}) and hydrogen (H{sub 2}) gas. The films were annealed at various temperatures ranging from 300 to 900 °C in steps of 200 °C using rapid thermal processor (RTP) in nitrogen ambient. Tribological properties of the DLC films were investigated by atomic force microscopy (AFM) in friction force microscopy (FFM) mode. The structural properties of the films were obtained by high resolution transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The wettability of the films was obtained using contact angle measurement. XPS analysis showed that the sp{sup 3} content is decreased from 75.2% to 24.1% while the sp{sup 2} content is increased from 24.8% to 75.9% when the temperature is changed from 300 to 900 °C. The contact angles of DLC films were higher than 70°. The FFM measurement results show that the highest friction coefficient value was achieved at 900 °C annealing temperature.

  12. Metal-doped diamond-like carbon films synthesized by filter-arc deposition

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) thin films are extensively utilized in the semiconductor, electric and cutting machine industries owing to their high hardness, high elastic modulus, low friction coefficients and high chemical stability. DLC films are prepared by ion beam-assisted deposition (BAD), sputter deposition, plasma-enhanced chemical vapor deposition (PECVD), cathodic arc evaporation (CAE), and filter arc deposition (FAD). The major drawbacks of these methods are the degraded hardness associated with the low sp3/sp2 bonding ratio, the rough surface and poor adhesion caused by the presence of particles. In this study, a self-developed filter arc deposition (FAD) system was employed to prepare metal-containing DLC films with a low particle density. The relationships between the DLC film properties, such as film structure, surface morphology and mechanical behavior, with variation of substrate bias and target current, are examined. Experimental results demonstrate that FAD-DLC films have a lower ratio, suggesting that FAD-DLC films have a greater sp3 bonding than the CAE-DLC films. FAD-DLC films also exhibit a low friction coefficient of 0.14 and half of the number of surface particles as in the CAE-DLC films. Introducing a CrN interfacial layer between the substrate and the DLC films enables the magnetic field strength of the filter to be controlled to improve the adhesion and effectively eliminate the contaminating particles. Accordingly, the FAD system improves the tribological properties of the DLC films

  13. Cavitation erosion resistance of diamond-like carbon coating on stainless steel

    Science.gov (United States)

    Cheng, Feng; Jiang, Shuyun

    2014-02-01

    Two diamond-like carbon (DLC) coatings are prepared on stainless steel 304 by cathodic arc plasma deposition technology at different substrate bias voltages and arc currents (-200 V/80 A, labeled DLC-1, and -100 V/60 A, labeled DLC-2). Cavitation tests are performed by using a rotating-disk test rig to explore the cavitation erosion resistance of the DLC coating. The mass losses, surface morphologies, chemical compositions and the phase constituents of the specimens after cavitation tests are examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the DLC-2 coatings can elongate the incubation period of stainless steel, leading to an excellent cavitation erosion resistance as compared to the untreated stainless steel specimens. After duration of 100 h cavitation test, serious damaged surfaces and plenty of scratches can be observed on the surfaces of the stainless steel specimens, while only a few grooves and tiny pits are observed on the DLC-2 coatings. It is concluded that, decreasing micro defects and increasing adhesion can reduce the delamination of DLC coating, and the erosion continues in the stainless steel substrate after DLC coating failure, and the eroded surface of the substrate is subjected to the combined action from cavitation erosion and slurry erosion.

  14. Antithrombogenicity of Fluorinated Diamond-Like Carbon Films Coated Nano Porous Polyethersulfone (PES Membrane

    Directory of Open Access Journals (Sweden)

    Norihisa Miki

    2013-09-01

    Full Text Available A nano porous polyethersulfone (PES membrane is widely used for aspects of nanofiltration, such as purification, fractionation and dialysis. However, the low-blood-compatibility characteristic of PES membrane causes platelets and blood cells to stick to the surface of the membrane and degrades ions diffusion through membrane, which further limits its application for dialysis systems. In this study, we deposited the fluorinated-diamond-like-carbon (F-DLC onto the finger like structure layer of the PES membrane. By doing this, we have the F-DLC films coating the membrane surface without sacrificing the membrane permeability. In addition, we examined antithrombogenicity of the F-DLC/PES membranes using a microfluidic device, and experimentally found that F-DLC drastically reduced the amount of blood cells attached to the surface. We have also conducted long-term experiments for 24 days and the diffusion characteristics were found to be deteriorated due to fouling without any surface modification. On the other hand, the membranes coated by F-DLC film gave a consistent diffusion coefficient of ions transfer through a membrane porous. Therefore, F-DLC films can be a great candidate to improve the antithrombogenic characteristics of the membrane surfaces in hemodialysis systems.

  15. Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies

    Energy Technology Data Exchange (ETDEWEB)

    Bouchet, M I De Barros [Laboratory of Tribology and System Dynamics, Ecole Centrale de Lyon, 69134 Ecully (France); Matta, C [Laboratory of Tribology and System Dynamics, Ecole Centrale de Lyon, 69134 Ecully (France); Le-Mogne, Th [Laboratory of Tribology and System Dynamics, Ecole Centrale de Lyon, 69134 Ecully (France); Martin, J Michel [Laboratory of Tribology and System Dynamics, Ecole Centrale de Lyon, 69134 Ecully (France); Zhang, Q [Materials and Process Simulation Center, California Institute of Technology, Pasadena CA (United States); III, W Goddard [Materials and Process Simulation Center, California Institute of Technology, Pasadena CA (United States); Kano, M [Nissan Research Center, to Kanagawa Industrial Technology Center, 705-1, 1 Shimo-imaizumi, Ebina, Kanagawa 243-0435 (Japan); Mabuchi, Y [Materials Engineering Department, Nissan Motor Co., Ltd., 6-1, Daikoku-cho, Tsurumi-ku, Yokohama (Japan); Ye, J [Research Department, NISSAN ARC LTD., 1 Natsushima-cho, Yokosuka 237-8523 (Japan)

    2007-11-15

    We report a unique tribological system that produces superlubricity under boundary lubrication conditions with extremely little wear. This system is a thin coating of hydrogen-free amorphous Diamond-Like-Carbon (denoted as ta-C) at 353 K in a ta-C/ta-C friction pair lubricated with pure glycerol. To understand the mechanism of friction vanishing we performed ToF-SIMS experiments using deuterated glycerol and {sup 13}C glycerol. This was complemented by first-principles-based computer simulations using the ReaxFF reactive force field to create an atomistic model of ta-C. These simulations show that DLC with the experimental density of 3.24 g/cc leads to an atomistic structure consisting of a 3D percolating network of tetrahedral (sp{sup 3}) carbons accounting for 71.5% of the total, in excellent agreement with the 70% deduced from our Auger spectroscopy and XANES experiments. The simulations show that the remaining carbons (with sp{sup 2} and sp{sup 1} character) attach in short chains of length 1 to 7. In sliding simulations including glycerol molecules, the surface atoms react readily to form a very smooth carbon surface containing OH-terminated groups. This agrees with our SIMS experiments. The simulations find that the OH atoms are mostly bound to surface sp{sup 1} atoms leading to very flexible elastic response to sliding. Both simulations and experiments suggest that the origin of the superlubricity arises from the formation of this OH-terminated surface.

  16. Preparation and investigation of diamond-like carbon stripper foils by filtered cathodic vacuum arc

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Qiwen, E-mail: fanqiwen0926@163.com [Department of Nuclear Physics, China Institute of Atomic Energy, P.O. Box 275(62), Beijing 102413 (China); Du, Yinghui; Zhang, Rong; Xu, Guoji [Department of Nuclear Physics, China Institute of Atomic Energy, P.O. Box 275(62), Beijing 102413 (China)

    2013-04-21

    Thin diamond-like carbon (DLC) stripper foils ∼5μg/cm{sup 2} in thickness were produced and evaluated as heavy-ion strippers for the Beijing HI-13 Tandem Accelerator. The DLC layers ∼4μg/cm{sup 2} in thickness were produced by the filtered cathodic vacuum arc technology onto glass slides coated with betaine–saccharose as releasing agent, which were previously covered with evaporated carbon layers ∼1μg/cm{sup 2} in thickness by the controlled ac arc-discharge method. Irradiation lifetimes of the DLC stripper foils were tested using the heavy-ion beams at the terminal of the Beijing HI-13 Tandem Accelerator, and compared with those of the standard carbon stripper foils made by the combined dc and ac arc-discharge method. The measurements indicate that the DLC stripper foils outlast the standard combined dc and ac arc-discharge carbon stripper foils by a factor of at least 13 and 4 for the {sup 197}Au{sup −} (∼9MeV, ∼1μA) and {sup 63}Cu{sup −} (∼9MeV, ∼1μA) ion beams, respectively. The structure and properties of the DLC foils deposited onto silicon substrates by the filtered cathodic vacuum arc technology were also evaluated and analyzed by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The scanning electron microscopy images show that the DLC foils contain hardly droplets through the double 90° filters. The X-ray photoelectron spectrum indicates that sp{sup 3} bonds of the DLC foils exceed 70%. The integral intensity ratio of the D peak to the G peak (I{sub D}/I{sub G}) measured by the Raman spectroscopy is 0.78.

  17. Dry And Ringer Solution Lubricated Tribology Of Thin Osseoconductive Metal Oxides And Diamond-Like Carbon Films

    Directory of Open Access Journals (Sweden)

    Waldhauser W.

    2015-09-01

    Full Text Available Achieving fast and strong adhesion to jawbone is essential for dental implants. Thin deposited films may improve osseointegration, but they are prone to cohesive and adhesive fracture due to high stresses while screwing the implant into the bone, leading to bared, less osteoconductive substrate surfaces and nano- and micro-particles in the bone. Aim of this work is the investigation of the cohesion and adhesion failure stresses of osteoconductive tantalum, titanium, silicon, zirconium and aluminium oxide and diamond-like carbon films. The tribological behaviour under dry and lubricated conditions (Ringer solution reveals best results for diamond-like carbon, while cohesion and adhesion of zirconium oxide films is highest.

  18. Fabrication of ZnO nanoparticles-embedded hydrogenated diamond-like carbon films by electrochemical deposition technique

    Institute of Scientific and Technical Information of China (English)

    Zhang Pei-Zeng; Li Rui-Shan; Pan Xiao-Jun; Xie Er-Qing

    2013-01-01

    ZnO nanoparticles-embedded hydrogenated diamond-like carbon (ZnO-DLC) films have been prepared by electrochemical deposition in ambient conditions.The morphology,composition,and microstructure of the films have been investigated.The results show that the resultant films are hydrogenated diamond-like carbon films embedded with ZnO nanoparticles in wurtzite structure,and the content and size of the ZnO nanoparticles increase with increasing deposition voltage,which are confirmed by X-ray photoelectron spectroscopy (XPS),Raman,and transmission electron microscope (TEM).Furthermore,a possible mechanism used to describe the growth process of ZnO-DLC films by electrochemical deposition is also discussed.

  19. Free standing diamond-like carbon thin films by PLD for laser based electrons/protons acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Thema, F.T.; Beukes, P.; Ngom, B.D. [UNESCO Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West, 7129, PO Box722, Western Cape Province (South Africa); Manikandan, E., E-mail: mani@tlabs.ac.za [UNESCO Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West, 7129, PO Box722, Western Cape Province (South Africa); Central Research Laboratory, Sree Balaji Medical College & Hospital (SBMCH), Chrompet, Bharath University, Chennai, 600044 (India); Maaza, M., E-mail: maaza@tlabs.ac.za [UNESCO Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West, 7129, PO Box722, Western Cape Province (South Africa)

    2015-11-05

    This study we reports for the first time on the synthesis and optical characteristics of free standing diamond-like carbon (DLC) deposited by pulsed laser deposition (PLD) onto graphene buffer layers for ultrahigh intensity laser based electron/proton acceleration applications. The fingerprint techniques of micro-Raman, UV–VIS–NIR and the IR spectroscopic investigations indicate that the suitability of such free standing DLC thin-films within the laser window and long wave infrared (LWIR) spectral range and hence their appropriateness for the targeted applications. - Highlights: • We report for the first time synthesis of free standing diamond-like carbon. • Pulsed laser deposition onto graphene buffer layers. • Fingerprint techniques of micro-Raman, UV–VIS–NIR and the IR spectroscopic investigations. • Ultrahigh intensity laser based electron/proton acceleration applications. • This material's suitable for the laser window and long wave infrared (LWIR) spectral range.

  20. A planar diamond-like carbon nanostructure for a low-voltage field emission cathode with a developed surface

    Science.gov (United States)

    Aban'shin, N. P.; Avetisyan, Yu. A.; Akchurin, G. G.; Loginov, A. P.; Morev, S. P.; Mosiyash, D. S.; Yakunin, A. N.

    2016-05-01

    Issues pertaining to the effective solution of problems related to the creation of durable low-voltage field emission cathodes with developed working surface and high density of emission current are considered. Results of practical implementation of the concept of multielectrode field emission planar nanostructures based on diamond-like carbon are presented. High average current density (0.1-0.3 A cm-2) is ensured by the formation of a controlled zone of electrostatic field localization at the planar-edge structure. The working life of cathode samples reaches 700-3000 h due to several positive factors, such as the stabilizing properties of a diamond-like carbon film, protection of the emitter from ion bombardment, use of a system of ballast resistors, and low-voltage operation of submicron interelectrode gaps.

  1. Free standing diamond-like carbon thin films by PLD for laser based electrons/protons acceleration

    International Nuclear Information System (INIS)

    This study we reports for the first time on the synthesis and optical characteristics of free standing diamond-like carbon (DLC) deposited by pulsed laser deposition (PLD) onto graphene buffer layers for ultrahigh intensity laser based electron/proton acceleration applications. The fingerprint techniques of micro-Raman, UV–VIS–NIR and the IR spectroscopic investigations indicate that the suitability of such free standing DLC thin-films within the laser window and long wave infrared (LWIR) spectral range and hence their appropriateness for the targeted applications. - Highlights: • We report for the first time synthesis of free standing diamond-like carbon. • Pulsed laser deposition onto graphene buffer layers. • Fingerprint techniques of micro-Raman, UV–VIS–NIR and the IR spectroscopic investigations. • Ultrahigh intensity laser based electron/proton acceleration applications. • This material's suitable for the laser window and long wave infrared (LWIR) spectral range

  2. Real contact temperatures as the criteria for the reactivity of diamond-like carbon coatings with oil additives

    OpenAIRE

    Kalin, Mitjan; Vižintin, Jože

    2015-01-01

    The operating conditions under which chemical reactions between diamond-like-carbon (DLC) coatings and oil additives occur and the main driving forces, i.e., the activation criteria for these chemical reactions, have not yet been defined. In order to clarify the difference between the test temperature and real contact temperature, and to determine the effect of the real contact temperature for these reactions, we have calculated the contact temperatures using two well-known models and compare...

  3. The influence of anti-wear additive ZDDP on doped and undoped diamond-like carbon coatings

    OpenAIRE

    Austin, L.; Liskiewicz, T; Kolev, I; Zhao, H.; Neville, A.

    2015-01-01

    Diamond-like carbon (DLC) coatings are recognised as a promising way to reduce friction and improve wear performance of automotive engine components. DLC coatings provide new possibilities in the improvement of the tribological performance of automotive components beyond what can be achieved with lubricant design alone. Lubricants are currently designed for metallic surfaces, the tribology of which is well defined and documented. DLC does not share this depth of tribological knowledge; thus, ...

  4. Interpreting the effects of interfacial chemistry on the tribology of diamond-like carbon coatings against steel in distilled water

    OpenAIRE

    Sutton, Daniel; Limbert, Georges; Burdett, Bary; R.J.K. Wood

    2013-01-01

    Three commercially available Diamond?Like Carbon (DLC) coatings were investigated to help understand the dynamics of transfer layer formation and decay, when sliding against AISI 52100 steel balls in distilled water. Optimum tribological behaviour was observed during interfacial sliding between the transfer layer and DLC coating. Alternatively, shear of the carbonaceous transfer layer from the contact region resulted in growth of an iron oxide layer comprised of magnetite, maghemite and hemat...

  5. Antimicrobial Properties of Diamond-Like Carbon/Silver Nanocomposite Thin Films Deposited on Textiles: Towards Smart Bandages

    OpenAIRE

    Tadas Juknius; Modestas Ružauskas; Tomas Tamulevičius; Rita Šiugždinienė; Indrė Juknienė; Andrius Vasiliauskas; Aušrinė Jurkevičiūtė; Sigitas Tamulevičius

    2016-01-01

    In the current work, a new antibacterial bandage was proposed where diamond-like carbon with silver nanoparticle (DLC:Ag)-coated synthetic silk tissue was used as a building block. The DLC:Ag structure, the dimensions of nanoparticles, the silver concentration and the silver ion release were studied systematically employing scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic absorption spectroscopy, respectively. Antimicrobial properties were investigated using micro...

  6. The Comparison of Biocompatibility Properties between Ti Alloys and Fluorinated Diamond-Like Carbon Films

    Directory of Open Access Journals (Sweden)

    Chavin Jongwannasiri

    2012-01-01

    Full Text Available Titanium and titanium alloys have found several applications in the biomedical field due to their unique biocompatibility. However, there are problems associated with these materials in applications in which there is direct contact with blood, for instance, thrombogenesis and protein adsorption. Surface modification is one of the effective methods used to improve the performance of Ti and Ti alloys in these circumstances. In this study, fluorinated diamond-like carbon (F-DLC films are chosen to take into account the biocompatible properties compared with Ti alloys. F-DLC films were prepared on NiTi substrates by a plasma-based ion implantation (PBII technique using acetylene (C2H2 and tetrafluoromethane (CF4 as plasma sources. The structure of the films was characterized by Raman spectroscopy. The contact angle and surface energy were also measured. Protein adsorption was performed by treating the films with bovine serum albumin and fibrinogen. The electrochemical corrosion behavior was investigated in Hanks’ solution by means of a potentiodynamic polarization technique. Cytotoxicity tests were performed using MTT assay and dyed fluorescence. The results indicate that F-DLC films present their hydrophobic surfaces due to a high contact angle and low surface energy. These films can support the higher albumin-to-fibrinogen ratio as compared to Ti alloys. They tend to suppress the platelet adhesion. Furthermore, F-DLC films exhibit better corrosion resistance and less cytotoxicity on their surfaces. It can be concluded that F-DLC films can improve the biocompatibility properties of Ti alloys.

  7. Microstructure and tribological performance of diamond-like carbon films deposited on hydrogenated rubber

    International Nuclear Information System (INIS)

    In this paper, the microstructure and tribological performance of diamond-like carbon (DLC) films prepared by plasma chemical vapor deposition on hydrogenated nitrile butadiene rubbers (HNBR) are studied. Different negative variations of temperature during film growth were selected by proper changes of the bias voltage. Raman measurements show a similar bonding regardless of the voltages used. A columnar growth and a tile-like microstructure of the DLC films were identified by scanning electron microscopy. Patch sizes can be correlated with the deposition conditions. The coefficient of friction (CoF) of DLC film coated HNBR was found to be much lower than that of the unprotected rubber, and more reduced for the DLC films with smaller patch sizes, which is explained by a better flexibility and conformity of the film during testing. In one of the samples, unexpected low CoF was observed, which was attributed to a modification of the mechanical properties of the rubber during the plasma treatment at high voltage. This issue was confirmed by X-ray photoelectron spectroscopy, which indicated a modification of the cross linking in the rubber. - Highlights: ► Bias voltage does not vary the chemical bonding and surface morphology of films. ► Film structure is patched, whose size depends on the etching and deposition voltages. ► The frictional behavior can be correlated with the patch size of the films. ► Surface analysis showed that rubber x-linking is modified by etching at high voltage. ► Modification of rubber x-linking leads to a different frictional behavior.

  8. Characterization of laboratory and industrial CrN/CrCN/diamond-like carbon coatings

    International Nuclear Information System (INIS)

    This work reports on laboratorial and experimental wear behaviour studies about a multi-layered film deposited by PVD (Physical Vapour Deposition) unbalanced magnetron sputtering. The film consists of three different layers: CrN in the bottom, CrCN as intermediate layer and DLC (diamond-like carbon) on the top. Film characterization was done using techniques such as Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Atomic Force Microscopy and X-ray diffraction. Scratch-tests, nanoindentation analysis and ball-cratering wear tests were used in order to measure the adhesion critical load, hardness and wear coefficient, respectively. Experimental tests were developed letting one to realise the suitability of this film for mould cavities used on injection moulding machines that produce automotive parts in polypropylene reinforced with 30% (wt.) glass fibres, because this composite material performs severe abrasion on injection moulding which brings important challenges to surface wear resistance. Experimental tests revealed that, after 135,000 injection cycles, multi-layer coating improved significantly the performance previously revealed by uncoated samples. The good results achieved by this film can be partially assigned to DLC top layer due to its low friction coefficient. This paper discusses these results, comparing them with some other PVD coatings already tested in the same conditions. - Highlights: • This coating presents a very good adhesion to the P20 steel substrate. • Surface wear performance is largely improved by the use of this coating. • Coating wear resistance is about 58.2 times higher than the uncoated substrate. • This film presents high suitability for application in mould cavities

  9. Electrical and magnetic properties of electrodeposited nickel incorporated diamond-like carbon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B., E-mail: pandey.beauty@yahoo.com [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Das, D. [UGC-DAE CSR, Sector III/LB-8, Bidhan Nagar, Kolkata 700098 (India); Kar, A.K. [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India)

    2015-05-15

    Highlights: • Electrical and magnetic properties of DLC and Ni-DLC thin films are studied. • The ohmicity and conductivity of DLC films rise with nickel addition. • The ohmicity of Ni-DLC is enhanced with increase in dilution of electrolyte. • Dielectric loss is high for Ni-DLC and decreases with frequency till 100 kHz. • (m–H) and (m–T) curves of Ni-DLC indicate superparamagnetic behavior. - Abstract: Nanocomposite diamond-like carbon (DLC) thin films have been synthesized by incorporating nickel (Ni) nanoparticles in DLC matrix with varying concentration of nickel. DLC and Ni-DLC thin films have been deposited on ITO coated glass substrates employing low voltage electrodeposition method. Electrical properties of the samples were studied by measuring current–voltage characteristics and dielectric properties. The current approaches toward an ohmic behavior with metal addition. This tendency of increasing ohmicity is enhanced with increase in dilution of the electrolyte. The conductivity increases with Ni addition and interestingly it continues to increase with dilution of Ni concentration in the electrolyte in the range of our study. Magnetic properties for DLC and Ni-DLC thin film samples were examined by electron paramagnetic resonance (EPR) measurements and Super Conducting Quantum Interference Device (SQUID) measurements. g-Value for DLC is 2.074, whereas it decreases to 2.055 with Ni addition in the electrolyte. This decrement arises from the increased sp{sup 2} content in DLC matrix. The magnetic moment vs. magnetic field (m–H) curves of Ni-DLC indicate superparamagnetic behavior which may be due to ferromagnetic contribution from the incorporated nickel nanoparticles in the DLC matrix. The ZFC curve of Ni-DLC after the blocking temperature shows a combined contribution of ferromagnetic, superparamagnetic and paramagnetic nature of the materials persisting up to 300 K.

  10. Engineering analysis of diamond-like carbon coated polymeric materials for biomedical applications.

    Science.gov (United States)

    Alanazi, A; Nojiri, C; Kido, T; Noguchi, T; Ohgoe, Y; Matsuda, T; Hirakuri, K; Funakubo, A; Sakai, K; Fukui, Y

    2000-08-01

    Diamond-like carbon (DLC) films have received much attention recently owing to their properties, which are similar to diamond: hardness, thermal conductivity, corrosion resistance against chemicals, abrasion resistance, good biocompatibility, and uniform flat surface. Furthermore, DLC films can be deposited easily on many substrates for wide area coat at room temperature. DLC films were developed for applications as biomedical materials in blood contacting-devices (e.g., rotary blood pump) and showed good biocompatibility for these applications. In this study, we investigated the surface roughness by Atomic Force Microscopy (AFM) and Hi-vision camera, SEM for surface imaging. The DLC films were produced by radio frequency glow discharge plasma decomposed of hydrocarbon gas at room temperature and low pressure (53 Pa) on several kinds of polycarbonate substrates. For the evaluation of the relation between deposition rate and platelet adhesion that we investigated in a previous study, DLC films were deposited at the same methane pressure for several deposition times, and film thickness was investigated. In addition, the deposition rate of DLC films on polymeric substrates is similar to the deposition rate of those deposited on Si substrates. There were no significant differences in substrates' surface roughness that were coated by DLC films in different deposition rates (16-40 nm). The surface energy and the contact angle of the DLC films were investigated. The chemical bond of DLC films also was evaluated. The evaluation of surface properties by many methods and measurements and the relationship between the platelet adhesion and film thickness is discussed. Finally, the presented DLC films appear to be promising candidates for biomedical applications and merit investigation. PMID:10971249

  11. Diamond-like carbon coatings for the protection of metallic artefacts: effect on the aesthetic appearance

    Science.gov (United States)

    Faraldi, Federica; Angelini, Emma; Caschera, Daniela; Mezzi, Alessio; Riccucci, Cristina; Caro, Tilde De

    2014-03-01

    Plasma-enhanced chemical vapour deposition (PECVD) is an environmentally friendly process used to deposit a variety of nano-structured coatings for the protection or the surface modification of metallic artefacts like the SiO2-like films that have been successfully tested on ancient silver, bronze and iron artefacts as barriers against aggressive agents. This paper deals with the preliminary results of a wider investigation aimed to the development of eco-sustainable coatings for the protection of Cu and Ag-based artefacts of archaeological and historic interest. Diamond-like carbon (DLC) coatings have been deposited by PECVD in different experimental conditions, in a capacitively coupled asymmetric plasma reactor, placing the substrates either on electrically powered electrode (cathodic mode) or grounded electrode (anodic mode) with and without hydrogen addition in the gas mixture. The final goal is to develop a coating with good protective effectiveness against aggressive atmospheres and contemporarily with negligible effects on the aesthetic appearance of the artefacts. The evaluation of possible colour changes of the surface patinas, due to coating process, was performed by optical microscopy and colorimetric measurements. Furthermore, to evaluate the reversibility of the thin DLC layer, an etching treatment in oxygen plasma has been successfully carried out and optimized. The chemical-physical characterization of the deposited DLC coatings was performed by means of the combined use of micro-Raman and XPS spectroscopies. The results show that the DLC films obtained in the anodic mode, may be proposed as a viable alternative to polymeric coatings for the protection of metallic ancient objects.

  12. Effect of nitrogen pressure on optical properties and microstructure of diamond-like carbon films grown by pulsed laser deposition

    Institute of Scientific and Technical Information of China (English)

    DING Xu-Li; LI Qing-Shan; KONG Xiang-he

    2009-01-01

    The effect of nitrogen pressure on optical properties of hydrogen-free diamond-like carbon (DLC) films deposited by pulsed laser ablation graphite in different background pressures of nitrogen is reported. By varying nitrogen pressures from 0.05 to 15.00 Pa, the photoluminescence is gradually increased and optical transmittance is gradually decreased. Atomic force microscopy (AFM) is used to observe the surface morphology of the DLC films. The results indicate that the surface becomes unsmoothed and there are some globose particles on the films surface with the rise of nitrogen pressures. The microstructure of the films is characterized using Raman spectroscopy.

  13. Diamond-like carbon films synthesized on bearing steel surface by plasma immersion ion implantation and deposition

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-xi; TANG Bao-yin; WANG Lang-ping; WANG Xiao-feng; YU Yong-hao; SUN Tao; HU Li-guo

    2004-01-01

    Diamond-like carbon (DLC) films were synthesized by plasma immersion ion implantation and deposition (PIIID) on 9Cr18 bearing steel surface. Influences of working gas pressure and pulse width of the bias voltage on properties of the thin film were investigated. The chemical compositions of the as-deposited films were characterized by Raman spectroscopy. The micro-hardness, friction and wear behavior, corrosion resistance of the samples were evaluated, respectively. Compared with uncoated substrates, micro-hardness results reveal that the maximum is increased by 88.7%. In addition, the friction coefficient decreases to about 0.1, and the corrosion resistance of treated coupons surface are improved significantly.

  14. Molecular dynamics simulations of the structures and mechanical properties of ZDOL polymer films on diamond-like carbon

    OpenAIRE

    Zhang, Yong-Wei

    2014-01-01

    One of the core technologies in the design and manufacture of the next-generation hard disk drives is the head-disk interface (HDI). The design of HDI must provide sufficient stability and durability for tens of thousands of hard drive start/stop cycles. However, the intermittent contacts between the head and disk are often unavoidable. To avoid and minimize disk damage, the surface of hard drive disks is often protected by a diamond-like carbon (DLC) coating, which is in turn covered by a th...

  15. Deposition of Diamond-Like carbon Films by High-Intensity Pulsed Ion Beam Ablation at Various Substrate Temperatures

    Institute of Scientific and Technical Information of China (English)

    梅显秀; 刘振民; 马腾才; 董闯

    2003-01-01

    Diamond-like carbon (DLC) films have been deposited on to Si substrates at substrate temperatures from 25℃to 400 ℃ by a high-intensity pulsed-ion-beam (HIPIB) ablation deposition technique. The formation of DLC is confirmed by Raman spectroscopy. According to an x-ray photoelectron spectroscopy analysis, the concentration of spa carbon in the films is about 40% when the substrate temperature is below 300 ℃. With increasing substrate temperature from 25 ℃ to 400 ℃, the concentration of sp3 carbon decreases from 43% to 8%. In other words,sp3 carbon is graphitized into sp2 carbon when the substrate temperature is above 300 ℃. The results of xray diffraction and atomic force microscopy show that, with increasing the substrate temperature, the surface roughness and the friction coefficient increase, and the microhardness and the residual stress of the films decrease.

  16. Composition and morphology of metal-containing diamond-like carbon films obtained by reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Corbella, C. [FEMAN Group, Departament de Fisica Aplicada i Optica, Universitat de Barcelona, Av. Diagonal 647, E08028 Barcelona (Spain)]. E-mail: corbella@ub.edu; Pascual, E. [FEMAN Group, Departament de Fisica Aplicada i Optica, Universitat de Barcelona, Av. Diagonal 647, E08028 Barcelona (Spain); Oncins, G. [Serveis Cientificotecnics, Universitat de Barcelona, PCB, c/ Josep Samitier 1-5, E08028 Barcelona (Spain); Canal, C. [Departamento de Tecnologia de Tensioactivos IQAB-CSIC, c/ Jordi Girona 18-26, E08034 Barcelona (Spain); Andujar, J.L. [FEMAN Group, Departament de Fisica Aplicada i Optica, Universitat de Barcelona, Av. Diagonal 647, E08028 Barcelona (Spain); Bertran, E. [FEMAN Group, Departament de Fisica Aplicada i Optica, Universitat de Barcelona, Av. Diagonal 647, E08028 Barcelona (Spain)

    2005-06-22

    The addition of metal atoms within the matrix of diamond-like carbon films leads to the improvement of their mechanical properties. The present paper discusses the relationship between the composition and morphology of metal-containing (W, Nb, Mo, Ti) diamond-like carbon thin films deposited at room temperature by reactive magnetron sputtering from a metal target in an argon and methane atmosphere. Composition was measured either by electron microprobe technique or by X-ray photoelectron spectroscopy and shows a smooth variation with relative methane flow. High relative methane flows lead to a bulk saturation of carbon atoms, which leads to a lack of homogeneity in the films as confirmed by secondary ion mass spectrometry. Cross-section micrographs were observed by transmission electron microscopy and revealed a structure strongly influenced by the metal inserted and its abundance. The surface pattern obtained by scanning electrochemical potential microscopy provided the metallicity distribution. These measurements were completed with atomic force microscopy of the surface. Selected area electron diffraction and X-ray diffraction measurements provided data of the crystalline structure along with nano-crystallite size. High-resolution transmission electron microscopy provided images of these crystallites.

  17. Gas Permeation, Mechanical Behavior and Cytocompatibility of Ultrathin Pure and Doped Diamond-Like Carbon and Silicon Oxide Films

    Directory of Open Access Journals (Sweden)

    Juergen M. Lackner

    2013-12-01

    Full Text Available Protective ultra-thin barrier films gather increasing economic interest for controlling permeation and diffusion from the biological surrounding in implanted sensor and electronic devices in future medicine. Thus, the aim of this work was a benchmarking of the mechanical oxygen permeation barrier, cytocompatibility, and microbiological properties of inorganic ~25 nm thin films, deposited by vacuum deposition techniques on 50 µm thin polyetheretherketone (PEEK foils. Plasma-activated chemical vapor deposition (direct deposition from an ion source was applied to deposit pure and nitrogen doped diamond-like carbon films, while physical vapor deposition (magnetron sputtering in pulsed DC mode was used for the formation of silicon as well as titanium doped diamond-like carbon films. Silicon oxide films were deposited by radio frequency magnetron sputtering. The results indicate a strong influence of nanoporosity on the oxygen transmission rate for all coating types, while the low content of microporosity (particulates, etc. is shown to be of lesser importance. Due to the low thickness of the foil substrates, being easily bent, the toughness as a measure of tendency to film fracture together with the elasticity index of the thin films influence the oxygen barrier. All investigated coatings are non-pyrogenic, cause no cytotoxic effects and do not influence bacterial growth.

  18. Ultra hydrophobic/superhydrophilic modified cotton textiles through functionalized diamond-like carbon coatings for self-cleaning applications.

    Science.gov (United States)

    Caschera, Daniela; Cortese, Barbara; Mezzi, Alessio; Brucale, Marco; Ingo, Gabriel Maria; Gigli, Giuseppe; Padeletti, Giuseppina

    2013-02-26

    A stable and improved control of the wettability of textiles was obtained by using a coating of diamond like carbon (DLC) films on cotton by PECVD. By controlling different plasma pretreatments of argon, oxygen, and hydrogen on the cotton fibers' surface, we have shown that the pretreatments had a significant impact on wettability behavior resulting from an induced nanoscale roughness combined with an incorporation of selected functional groups. Upon subsequent deposition of diamond like carbon (DLC) films, the cotton fibers yield to a highly controlled chemical stability and hydrophobic state and could be used for self-cleaning applications. By controlling the nature of the plasma pretreatment we have shown that the oxygen plasma pretreatment was more effective than the argon and hydrogen for the superhydrophilic/ultra hydrophobic properties. The chemical and morphological changes of the cotton fibers under different treatments were characterized using X-ray photoelectron and Raman spectroscopy, AFM, and water contact angle measurements. The mechanism underlying the water-repellent properties of the cotton fibers provides a new and innovative pathway into the development of a range of advanced self-cleaning textiles. PMID:23379650

  19. Development of a radio frequency atmospheric pressure plasma jet for diamond-like carbon coatings on stainless steel substrates

    Science.gov (United States)

    Sohbatzadeh, F.; Samadi, O.; Siadati, S. N.; Etaati, G. R.; Asadi, E.; Safari, R.

    2016-10-01

    In this paper, an atmospheric pressure plasma jet with capacitively coupled radio frequency discharge was developed for diamond-like carbon (DLC) coatings on stainless steel substrates. The plasma jet was generated by argon-methane mixture and its physical parameters were investigated. Relation between the plasma jet length and width of the powered electrode was discussed. Optical and electrical characteristics were studied by optical emission spectroscopy, voltage and current probes, respectively. The evolutions of various species like ArI, C2 and CH along the jet axis were investigated. Electron temperature and density were estimated by Boltzmann plot method and Saha-Boltzmann equation, respectively. Finally, a diamond-like carbon coating was deposited on stainless steel-304 substrates by the atmospheric pressure radio frequency plasma jet in ambient air. Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy and Vickers hardness test were used to study the deposited films. The length of the jet was increased by increasing the width of the powered electrode. The estimated electron temperature and density were 1.43 eV and 1.39 × 1015 cm-3, respectively. Averaged Vicker's hardness of the coated sample was three times greater than that of the substrate. The SEM images of the deposited thin films revealed a 4.5 μm DLC coated for 20 min.

  20. Ultrathin diamond-like carbon films deposited by filtered carbon vacuum arcs

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre; Fong, Walton; Kulkarni, Ashok; Ryan, Francis W.; Bhatia, C. Singh

    2001-07-13

    Ultrathin (< 5 nm) hard carbon films are of great interest to the magnetic storage industry as the areal density approaches 100 Gbit/in{sup 2}. These films are used as overcoats to protect the magnetic layers on disk media and the active elements of the read-write slider. Tetrahedral amorphous carbon films can be produced by filtered cathodic arc deposition, but the films will only be accepted by the storage industry only if the ''macroparticle'' issue has been solved. Better plasma filters have been developed over recent years. Emphasis is put on the promising twist filter system - a compact, open structure that operates with pulsed arcs and high magnetic field. Based on corrosion tests it is shown that the macroparticle reduction by the twist filter is satisfactory for this demanding application, while plasma throughput is very high. Ultrathin hard carbon films have been synthesized using S-filter and twist filter systems. Film properties such as hardness, elastic modulus, wear, and corrosion resistance have been tested.

  1. Characteristics of Nitrogen Doped Diamond-Like Carbon Films Prepared by Unbalanced Magnetron Sputtering for Electronic Devices.

    Science.gov (United States)

    Lee, Jaehyeong; Choi, Byung Hui; Yun, Jung-Hyun; Park, Yong Seob

    2016-05-01

    Synthetic diamond-like carbon (DLC) is a carbon-based material used mainly in cutting tool coatings and as an abrasive material. The market for DLC has expanded into electronics, optics, and acoustics because of its distinct electrical and optical properties. In this work, n-doped DLC (N:DLC) films were deposited on p-type silicon substrates using an unbalanced magnetron sputtering (UBMS) method. We investigated the effect of the working pressure on the microstructure and electrical properties of n-doped DLC films. The structural properties of N:DLC films were investigated by Raman spectroscopy and SEM-EDX, and the electrical properties of films were investigated by observing the changes in the resistivity and current-voltage (I-V) properties. The N:DLC films prepared by UBMS in this study demonstrated good conducting and physical properties with n-doping. PMID:27483841

  2. Characteristics of Nitrogen Doped Diamond-Like Carbon Films Prepared by Unbalanced Magnetron Sputtering for Electronic Devices.

    Science.gov (United States)

    Lee, Jaehyeong; Choi, Byung Hui; Yun, Jung-Hyun; Park, Yong Seob

    2016-05-01

    Synthetic diamond-like carbon (DLC) is a carbon-based material used mainly in cutting tool coatings and as an abrasive material. The market for DLC has expanded into electronics, optics, and acoustics because of its distinct electrical and optical properties. In this work, n-doped DLC (N:DLC) films were deposited on p-type silicon substrates using an unbalanced magnetron sputtering (UBMS) method. We investigated the effect of the working pressure on the microstructure and electrical properties of n-doped DLC films. The structural properties of N:DLC films were investigated by Raman spectroscopy and SEM-EDX, and the electrical properties of films were investigated by observing the changes in the resistivity and current-voltage (I-V) properties. The N:DLC films prepared by UBMS in this study demonstrated good conducting and physical properties with n-doping.

  3. Structural characteristics of surface-functionalized nitrogen-doped diamond-like carbon films and effective adjustment to cell attachment

    Science.gov (United States)

    Liu, Ai-Ping; Liu, Min; Yu, Jian-Can; Qian, Guo-Dong; Tang, Wei-Hua

    2015-05-01

    Nitrogen-doped diamond-like carbon (DLC:N) films prepared by the filtered cathodic vacuum arc technology are functionalized with various chemical molecules including dopamine (DA), 3-Aminobenzeneboronic acid (APBA), and adenosine triphosphate (ATP), and the impacts of surface functionalities on the surface morphologies, compositions, microstructures, and cell compatibility of the DLC:N films are systematically investigated. We demonstrate that the surface groups of DLC:N have a significant effect on the surface and structural properties of the film. The activity of PC12 cells depends on the particular type of surface functional groups of DLC:N films regardless of surface roughness and wettability. Our research offers a novel way for designing functionalized carbon films as tailorable substrates for biosensors and biomedical engineering applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 51272237, 51272231, and 51010002) and the China Postdoctoral Science Foundation (Grant Nos. 2012M520063, 2013T60587, and Bsh1201016).

  4. The effect of temperature on the tribological mechanisms and reactivity of hydrogenerated, amorphous diamond-like carbon coatings under oil-lubricated conditions

    OpenAIRE

    Roman, E.; Kalin, Mitjan; Vižintin, Jože

    2015-01-01

    In this work we present the wear and friction behaviour of boundary-lubricated, hydrogenated, amorphous, diamond-like carbon coatings (a-C:H), in self-mated a-C:H/a-C:H contacts, at three different testing temperaturesČ 20, 80, 150 °C. We present results from Auger electron spectroscopy, X-ray photoelectron spectroscopy and Raman analyses relating to the chemical and structural changes in the diamond-like carbon coatings duringsliding in the presence of mineral oil, with and without additives...

  5. Synthesis of diamond-like carbon films on Si substrates by photoemission-assisted plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Meng [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Ogawa, Shuichi, E-mail: ogasyu@tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Takabayashi, Susumu; Otsuji, Taiichi [Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Core Research for Evolutionary Science and Technology, Japan Science and Technology Agency, K' s Gobancho Bldg., 7 Gobancho, Chiyoda-ku, Tokyo 102-0076 (Japan); Takakuwa, Yuji [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2012-11-15

    Diamond-like carbon (DLC) films grown by photoemission-assisted plasma-enhanced chemical vapor deposition (PA-PECVD) have attracted attention as a gate insulator for graphene-channel field effect transistors (GFETs). In this study, the possibility of using PA-PECVD to grow insulating DLC films for GFETs is explored by focusing on the growth rate and uniformity of DLC films on Si substrates. Initially, the DLC films were formed at a constant rate but the growth rate decreased rapidly when the thickness reached approximately 400 nm. This is because of a decrease in photoelectron emissions from the Si substrates as they are covered by DLC films which absorb UV photons. However, the DLC films formed uniformly at thicknesses less than 16%. This result indicates that PA-PECVD is a promising method for growing DLC films as the gate dielectric layer of GFETs.

  6. Thermal effects on structure and photoluminescence properties of diamond-like carbon films prepared by pulsed laser deposition

    Institute of Scientific and Technical Information of China (English)

    CHEN Da; LI Qing-shan; WANG Jing-jing; ZHENG Xue-gang

    2006-01-01

    Un-hydrogenated Diamond-like Carbon (DLC) films were prepared by pulsed laser deposition technique at different substrate temperature.The Raman spectra,the absorption and the photoluminescence spectra were measured.The dependence of structure and photoluminescence properties on deposition temperature were studied in detail.The experimental results indicate that the sp2 sites form small clusters that consist of both olefinic chains and aromatic ring groups within the sp3 matrix.With raising deposition temperature,the optical band gaps increase from 1.87 to 2.85 eV.The main band of photoluminescence centered at around 700nm shifts to short wavelength,and the intensity of this band increases.The photoluminescence can be attributed to carrier localization within an increasing sp2 clusters.It was clarified that the DLC films are ordered with increasing deposition temperature.

  7. Hydrophobic and high transparent honeycomb diamond-like carbon thin film fabricated by facile self-assembled nanosphere lithography

    Science.gov (United States)

    Peng, Kai-Yu; Wei, Da-Hua; Lin, Chii-Ruey; Yu, Yueh-Chung; Yao, Yeong-Der; Lin, Hong-Ming

    2014-01-01

    In this paper, we take advantage of a facile fabrication technique called self-assembled nanosphere lithography (SANSL) combining with proper two-step reactive ion etching (RIE) method and radio frequency (RF) sputtering deposition process for manufacturing honeycomb diamond-like carbon (DLC) thin film structures with hydrophobic and high transparent properties. It is found that the DLC thin films deposited on clean glass substrates at the RF power of 100 W with the surface roughness (Ra) of 2.08 nm and the ID/IG ratio of 1.96 are realized. With a fill-factor of 0.691, the honeycomb DLC patterned thin film shows the best transmittance performance of 87% in the wavelength of visible light, and the optimized contact angle measurement is ˜108°. Compared with the pure DLC thin film and original glass substrate, the hydrophobic property of the patterned DLC films is significantly improved by 80 and 160%, respectively.

  8. Defect effect on tribological behavior of diamond-like carbon films deposited with hydrogen diluted benzene gas in aqueous environment

    Science.gov (United States)

    Yi, Jin Woo; Park, Se Jun; Moon, Myoung-Woon; Lee, Kwang-Ryeol; Kim, Seock-Sam

    2009-05-01

    This study examined the friction and wear behavior of diamond-like carbon (DLC) films deposited from a radio frequency glow discharge using a hydrogen diluted benzene gas mixture. The DLC films were deposited on Si (1 0 0) and polished stainless steel substrates by radio frequency plasma-assisted chemical vapor deposition (r.f.-PACVD) at hydrogen to benzene ratios, or the hydrogen dilution ratio, ranging from 0 to 2.0. The wear test was carried out in both ambient and aqueous environments using a homemade ball-on-disk type wear rig. The stability of the DLC coating in an aqueous environment was improved by diluting the benzene precursor gas with hydrogen, suggesting that hydrogen dilution during the deposition of DLC films suppressed the initiation of defects in the film and improved the adhesion of the coating to the interface.

  9. Durability evaluation of perfluoropolyether-lubricant-coated protective diamond-like carbon film by the lateral vibration friction test

    International Nuclear Information System (INIS)

    An investigation of the perfluoropolyether (PFPE) lubricant effect on the tribological properties of diamond-like carbon (DLC) film magnetic hard disks was conducted. On the basis of friction force microscopy techniques, we carried out lateral oscillation wear tests to detect DLC film disks with and without PFPE lubricant. The results reveal that the DLC film without lubricant easily fractures and swells. In contrast, the transfer of free lubricant and the progressive destruction of bonding lubricant were observed on the DLC film coated with a PFPE lubricant. The dynamic deformation and durability evaluation of the PFPE lubricant and DLC film system were observed in the lateral oscillation wear test by changing the experimental load and amplitude of lateral vibration applied to a cantilever tip. The destruction of the PFPE-DLC film occurred in the test of the 10 nm oscillation amplitude due to the breaking off of the molecular chain of PFPE

  10. Synthesis and tribological behaviors of diamond-like carbon films by electrodeposition from solution of acetonitrile and water

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) films were prepared on silicon substrates by liquid phase electrodeposition from a mixture of acetonitrile and deionized water. The deposition voltage was clearly reduced owing to the presence of deionized water in the electrolyte by changing the basic properties (dielectric constant and dipole moment) of the electrolyte. Raman spectra reveal that the ratio of sp3/sp2 in the DLC films is related to the concentration of acetonitrile. The surface roughness and grain morphology determined by atomic force microscopy are also influenced by the concentration of the acetonitrile. The UMT-2 universal micro-tribometer was used to test the friction properties of the DLC films obtained from electrolytes with different concentration. The results convey that the DLC film prepared from the electrolyte containing 10 vol.% acetonitrile has the better surface morphology and friction behavior comparing with the other. In addition the growth mechanism of the film was also discussed

  11. Nanopatterning on silicon surface using atomic force microscopy with diamond-like carbon (DLC-coated Si probe

    Directory of Open Access Journals (Sweden)

    Zhou Jingfang

    2011-01-01

    Full Text Available Abstract Atomic force microscope (AFM equipped with diamond-like carbon (DLC-coated Si probe has been used for scratch nanolithography on Si surfaces. The effect of scratch direction, applied tip force, scratch speed, and number of scratches on the size of the scratched geometry has been investigated. The size of the groove differs with scratch direction, which increases with the applied tip force and number of scratches but decreases slightly with scratch speed. Complex nanostructures of arrays of parallel lines and square arrays are further fabricated uniformly and precisely on Si substrates at relatively high scratch speed. DLC-coated Si probe has the potential to be an alternative in AFM-based scratch nanofabrication on hard surfaces.

  12. Corrosion behavior of aluminum doped diamond-like carbon thin films in NaCl aqueous solution.

    Science.gov (United States)

    Khun, N W; Liu, E

    2010-07-01

    Aluminum doped diamond-like carbon (DLC:Al) thin films were deposited on n-Si(100) substrates by co-sputtering a graphite target under a fixed DC power (650 W) and an aluminum target under varying DC power (10-90 W) at room temperature. The structure, adhesion strength and surface morphology of the DLC:Al films were characterized by X-ray photoelectron spectroscopy (XPS), micro-scratch testing and atomic force microscopy (AFM), respectively. The corrosion performance of the DLC:Al films was investigated by means of potentiodynamic polarization testing in a 0.6 M NaCl aqueous solution. The results showed that the polarization resistance of the DLC:Al films increased from about 18 to 30.7 k(omega) though the corrosion potentials of the films shifted to more negative values with increased Al content in the films. PMID:21128496

  13. Preparation of diamond-like carbon and boron nitirde films by high-intensity pulsed ion beam deposition

    Energy Technology Data Exchange (ETDEWEB)

    Rej, D.J.; Davis, H.A. [Los Alamos National Lab., NM (United States); Remnev, G.E. [Tomsk Polytechnic Univ., Tomsk (Russian Federation). Nuclear Physics Institute.] [and others

    1995-05-01

    Intense ion beams (300-keV C{sup +}, O{sup +}, and H{sup +}, 20--30 kA, 50 to 400-ns pulsewidth, up to 0.3-Hz repetition rate) were used to prepare diamond-like carbon (DLC) and boron nitride (BN) films. Deposition rates of up to 25{plus_minus}5 nm/pulse were obtained with instantaneous rates exceeding 1 mm/s. Most films were uniform, light brown, translucent, and nonporous with some micron-size particulates. Raman and parallel electron energy loss spectroscopy indicated the presence of DLC. The films possessed favorable electron field-emission characteristics desirable for cold-cathode displays. Transmission electron microscopy (TEM) and transmission electron diffraction (TED) revealed that the C films contained diamond crystals with 25 to 125-nm grain size. BN films were composed of hexagonal, cubic and wurtzite phases.

  14. Preparation of Diamond-Like carbon Films in methane by Electron Cyclotron Resonance Microwave Plasma Source Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    李新; 唐祯安; 马国佳; 吴志猛; 邓新绿

    2003-01-01

    Diamond-like carbon (DLC) films were prepared on Si (100) substrates by ion implantation from an electron cyclotron resonance microwave plasma source. During the implantation, 650 W microwave power was used to produce discharge plasma with methane as working gas, and -20 kV voltage pulses were applied to the substrate holder to accelerate ions in the plasma. Confocal Raman spectra confirmed the DLC characteristics of the films.Fourier-transform infrared characterization indicates that the DLC films were composed of sp3 and sp2 carbonbonded hydrogen. The hardness of the films was evaluated with a Nano Indenter-XP System. The result shows that the highest hardness value was 14.6GPa. The surface rms roughness of the films was as low as 0. 104nm measured with an atomic force microscope. The friction coefficient of the films was checked using a ball-on-disk microtribometer. The average friction coefficient is approximately 0.122.

  15. Investigation of Physical Properties and Electrochemical Behavior of Nitrogen-Doped Diamond-Like Carbon Thin Films

    Directory of Open Access Journals (Sweden)

    Rattanakorn Saensak

    2014-03-01

    Full Text Available This work reports characterizations of diamond-like carbon (DLC films used as electrodes for electrochemical applications. DLC thin films are prepared on glass slides and silicon substrates by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD using a gas mixture of methane and hydrogen. In addition, the DLC films are doped with nitrogen in order to reduce electrical resistivity. Compared to the undoped DLC films, the electrical resistivity of nitrogen-doped (N-doped DLC films is decreased by three orders of magnitude. Raman spectroscopy and UV/Vis spectroscopy analyses show the structural transformation in N-doped DLC films that causes the reduction of band gap energy. Contact angle measurement at N-doped DLC films indicates increased hydrophobicity. The results obtained from the cyclic voltammetry measurements with Fe(CN63-/Fe(CN64- redox species exhibit the correlation between the physical properties and electrochemical behavior of DLC films.

  16. Impact of the difference in power frequency on diamond-like carbon thin film coating over 3-dimensional objects

    International Nuclear Information System (INIS)

    With a type of capacitatively coupled plasma enhanced chemical vapor deposition (PECVD) technique, where two specially designed electrodes face to each other, the inner surface of hollow 3-dimensional objects such as poly(ethylene terephthalate) (PET) bottles can be coated with diamond-like carbon (DLC) thin film. DLC-coated PET bottles obtained with this technique have an enhanced gas barrier property, and therefore are applicable to industrial use such as for the extension of the shelf-life of contents sensitive to gas permeation. In this paper, the impact of power frequency ranging from 2.5 to 13.56 MHz was studied in order to research the behavior of plasma inside PET bottles and resultant properties. Different power frequency turned out to be influential on gas barrier property, the overall and distribution of tint, and adhesion between DLC and PET substrate. In addition, positron annihilation turned out to be powerful tool for the comparison of different coating conditions because it clarifies the homogeneity of DLC thin films through providing information on overall structure and thickness of them. These findings can be used for the optimization not only in the beverage PET bottle application, but also in other capacitatively coupled PECVD devices. - Highlights: • We demonstrated an effective methodology for the homogeneity of thin films. • We described the influence of power frequency on plasma and resultant thin film. • Diamond-like carbon coated on poly(ethylene terephthalate) bottles was used. • Different frequency provided homogenous thin films based on the above methodology. • For the industrial performance of the bottles, optimization was found at 6 MHz

  17. Impact of the difference in power frequency on diamond-like carbon thin film coating over 3-dimensional objects

    Energy Technology Data Exchange (ETDEWEB)

    Nakaya, Masaki, E-mail: m-nakaya@kirin.co.jp [Packaging Technology Development Center, Technology Development Department, Kirin Brewery Co., Ltd., 1-17-1 Namamugi, Tsurumi-ku, Yokohama, Kanagawa 230-8682 (Japan); Shimizu, Mari [Packaging Technology Development Center, Technology Development Department, Kirin Brewery Co., Ltd., 1-17-1 Namamugi, Tsurumi-ku, Yokohama, Kanagawa 230-8682 (Japan); Uedono, Akira [Division of Applied Physics, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)

    2014-08-01

    With a type of capacitatively coupled plasma enhanced chemical vapor deposition (PECVD) technique, where two specially designed electrodes face to each other, the inner surface of hollow 3-dimensional objects such as poly(ethylene terephthalate) (PET) bottles can be coated with diamond-like carbon (DLC) thin film. DLC-coated PET bottles obtained with this technique have an enhanced gas barrier property, and therefore are applicable to industrial use such as for the extension of the shelf-life of contents sensitive to gas permeation. In this paper, the impact of power frequency ranging from 2.5 to 13.56 MHz was studied in order to research the behavior of plasma inside PET bottles and resultant properties. Different power frequency turned out to be influential on gas barrier property, the overall and distribution of tint, and adhesion between DLC and PET substrate. In addition, positron annihilation turned out to be powerful tool for the comparison of different coating conditions because it clarifies the homogeneity of DLC thin films through providing information on overall structure and thickness of them. These findings can be used for the optimization not only in the beverage PET bottle application, but also in other capacitatively coupled PECVD devices. - Highlights: • We demonstrated an effective methodology for the homogeneity of thin films. • We described the influence of power frequency on plasma and resultant thin film. • Diamond-like carbon coated on poly(ethylene terephthalate) bottles was used. • Different frequency provided homogenous thin films based on the above methodology. • For the industrial performance of the bottles, optimization was found at 6 MHz.

  18. Preparation of self-supporting diamond-like carbon nanofoils with thickness less than 5 nm for laser-driven ion acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Ma Wenjun [Faculty for Physics, LMU Munich, Am Coulombwall 1, D-85748 Garching (Germany); Max-Planck-Institute for Quantumoptics, Hans-Kopfermann-Str. 1, 85748 Garching (Germany); Liechtenstein, V.Kh. [RRC Kurchatov Institute, 123182 Moscow (Russian Federation); Szerypo, J. [Faculty for Physics, LMU Munich, Am Coulombwall 1, D-85748 Garching (Germany); Maier-Leibnitz Laboratory (MLL), D-85748 Garching (Germany); Jung, D. [Faculty for Physics, LMU Munich, Am Coulombwall 1, D-85748 Garching (Germany); Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hilz, P. [Faculty for Physics, LMU Munich, Am Coulombwall 1, D-85748 Garching (Germany); Hegelich, B.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Maier, H.J. [Faculty for Physics, LMU Munich, Am Coulombwall 1, D-85748 Garching (Germany); Maier-Leibnitz Laboratory (MLL), D-85748 Garching (Germany); Schreiber, J. [Max-Planck-Institute for Quantumoptics, Hans-Kopfermann-Str. 1, 85748 Garching (Germany); Habs, D., E-mail: Dietrich.Habs@Physik.Uni-Muenchen.de [Faculty for Physics, LMU Munich, Am Coulombwall 1, D-85748 Garching (Germany); Max-Planck-Institute for Quantumoptics, Hans-Kopfermann-Str. 1, 85748 Garching (Germany)

    2011-11-01

    Ultrathin (<5 nm) self-supporting diamond-like carbon (DLC) foils are prepared by filtered cathodic vacuum arc (FCVA) deposition method as targets for laser-driven ion acceleration. The thickness and the morphology of these foils are characterized by atomic force microscope (AFM) and scanning electron microscope (SEM).

  19. Ion beam deposition of amorphous carbon films with diamond like properties

    Science.gov (United States)

    Angus, John C.; Mirtich, Michael J.; Wintucky, Edwin G.

    1982-01-01

    Carbon films were deposited on silicon, quartz, and potassium bromide substrates from an ion beam. Growth rates were approximately 0.3 micron/hour. The films were featureless and amorphous and contained only carbon and hydrogen in significant amounts. The density and carbon/hydrogen ratio indicate the film is a hydrogen deficient polymer. One possible structure, consistent with the data, is a random network of methylene linkages and tetrahedrally coordinated carbon atoms.

  20. Transition Metal Ion Implantation into Diamond-Like Carbon Coatings: Development of a Base Material for Gas Sensing Applications

    Directory of Open Access Journals (Sweden)

    Andreas Markwitz

    2015-01-01

    Full Text Available Micrometre thick diamond-like carbon (DLC coatings produced by direct ion deposition were implanted with 30 keV Ar+ and transition metal ions in the lower percentage (<10 at.% range. Theoretical calculations showed that the ions are implanted just beneath the surface, which was confirmed with RBS measurements. Atomic force microscope scans revealed that the surface roughness increases when implanted with Ar+ and Cu+ ions, whereas a smoothing of the surface from 5.2 to 2.7 nm and a grain size reduction from 175 to 93 nm are measured for Ag+ implanted coatings with a fluence of 1.24×1016 at. cm−2. Calculated hydrogen and carbon depth profiles showed surprisingly significant changes in concentrations in the near-surface region of the DLC coatings, particularly when implanted with Ag+ ions. Hydrogen accumulates up to 32 at.% and the minimum of the carbon distribution is shifted towards the surface which may be the cause of the surface smoothing effect. The ion implantations caused an increase in electrical conductivity of the DLC coatings, which is important for the development of solid-state gas sensors based on DLC coatings.

  1. STRUCTURE, MECHANICAL PROPERTIES AND THERMAL STABILITY OF DIAMOND-LIKE CARBON FILMS PREPARED BY ARC ION PLATING

    Institute of Scientific and Technical Information of China (English)

    Y.S. Zou; J.D. Zheng; J. Gong; C. Sun; R.F. Huang; L.S. Wen

    2005-01-01

    Diamond-like Carbon (DLC) films have been prepared on Si(100) substrates by arc ion plating in conjunction with pulse bias voltage under H2 atmosphere. The deposited films have been characterized by scanning electron microscopy and atomic force microscopy. The results show that the surface of the film is smooth and dense without any cracks, and the surface roughness is low. The bonding characteristic of the films has been studied by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. It shows the sp3 bond content of the film deposited at -200V is 26.7%. The hardness and elastic modulus of the film determined by nanoindentation technique are 30.8 and 250.1GPa, respectively. The tribological characteristic of the films reveals that they have low friction coefficient and good wear-resistance. After deposition, the films have been annealed in the range of 350-700℃ for 1h in vacuum to investigate the thermal stability. Raman spectra indicate that the ID/IG ratio and G peak position have few detectable changes below 500℃. Further increasing the annealing temperature, the hydrogen can be released, the structure rearranges, and the phase transition of sp3 configured carbon to sp2 configured carbon appears.

  2. Study of Fluorine Addition Influence in the Dielectric Constant of Diamond-Like Carbon Thin Film Deposited by Reactive Sputtering

    Science.gov (United States)

    Trippe, S. C.; Mansano, R. D.

    The hydrogenated amorphous carbon films (a-C:H) or DLC (Diamond-Like Carbon) films are well known for exhibiting high electrical resistivity, low dielectric constant, high mechanical hardness, low friction coefficient, low superficial roughness and also for being inert. In this paper, we produced fluorinated DLC films (a-C:F), and studied the effect of adding CF4 on the above-mentioned properties of DLC films. These films were produced by a reactive RF magnetron sputtering system using a target of pure carbon in stable graphite allotrope. We performed measurements of electrical characteristic curves of capacitance as a function of applied tension (C-V) and current as a function of the applied tension (I-V). We showed the dielectric constant (k) and the resistivity (ρ) as functions of the CF4 concentration. On films with 65% CF4, we found that k = 2.7, and on films with 70% CF4, ρ = 12.3 × 1011 Ω cm. The value of the electrical breakdown field to films with 70% CF4 is 5.3 × 106 V/cm.

  3. Acetylene - Argon Plasmas Measured at a Biased Substrate Electrode for Diamond-Like Carbon Deposition. Part 2: Ion Energy Distributions

    CERN Document Server

    Baby, A; Lemoine, P; Maguire, P D

    2008-01-01

    Ion energy distributions have been determined at the rf-bias electrode in an inductively-coupled acetylene-argon plasma for various substrate bias voltages and frequencies under conditions suitable for film deposition. These are compared with those obtained at the grounded wall of a capacitively coupled plasma. In the former, for pressures up to 25 mTorr, the IEDs exhibit bimodal structures with peak separation values that follow the expected dependence on voltage and frequency. At higher pressures, 120 mTorr, the bimodal structure is replaced by a single peak. For all conditions, the dominant ion is Ar+ or ArH+ despite a set C2H2:Ar flow ratio of 2:1, and this can be attributed to the high electron dissociation of the parent molecule. Diamond-like carbon films indicate a peak hardness at an ion energy of around 90 eV and a very sharp fall in hardness is noted beyond this value. This is similar to the observed bombardment energy relationship for sp3 bond formation in hydrogen-free tetragonal amorphous carbon ...

  4. Time-resolved electrical measurements of a pulsed-dc methane discharge used in diamond-like carbon films production

    International Nuclear Information System (INIS)

    Amorphous hydrogenated carbon (a-C:H) thin films were obtained at room temperature via asymmetric bipolar pulsed-dc methane glow discharge. The power frequency values were varied from 100 to 200 kHz and the maximum amplitude voltage from -600 to -1400 V. Such films present diamond-like carbon (DLC) properties [J.L. Andujar, M. Vives, C. Corbella, E. Bertran, Diamond Relat. Mater. 12 (2003) 98]. The plasma, powered by a pulse frequency of 100 kHz, was electrically studied by a Langmuir probe. The next parameters were calculated within the pulse cycle from I-V measurements with 1 μs resolution: plasma and floating potentials, electron temperature, and electron and ion densities. The presence of a population of hot electrons (10 eV) was detected at high bias voltage region. The density of cold electrons grows one order of magnitude after each negative pulse, whereas the ion density suffers a prompt increase during each positive pulse. The surface topography of DLC films was scanned by atomic force microscopy (AFM). A smoothly varying friction coefficient (between 0.2 and 0.3) was measured by AFM in contact mode. X-ray reflectivity (XRR) analysis provided a wide characterization of the films, involving density, thickness and roughness. The C/H ratio, as directly obtained by elemental analysis (EA), shows an increase at higher bias voltages. All these features are discussed in terms of process parameters varied in film growth

  5. Preparation of diamond-like carbon films in methane by electron cyclotron resonance microwave plasma source ion implantation

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) films were prepared on Si(100) substrates by ion implantation from an electron cyclotron resonance microwave plasma source. During the implantation, 650 W microwave power was used to produce discharge plasma with methane as working gas, and -20 kV voltage pulses were applied to the substrate holder to accelerate ions in the plasma. Confocal Raman spectra confirmed the DLC characteristics of the films. Fourier-transform infrared characterization indicates that the DLC films were composed of sp3 and sp2 carbon-bonded hydrogen. The hardness of the films was evaluated with a Nano Indenter-XP System. The result shows that the highest hardness value was 14.6 GPa. The surface rms roughness of the films was as low as 0.104 nm measured with an atomic force microscope. The friction coefficient of the films was checked using a ball-on-disk microtribometer. The average friction coefficient is approximately 0.122

  6. Structure analysis of silicon-doped diamond-like carbon films by X-ray and neutron reflectivity measurements

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) is an amorphous material with an intermediate chemical structure between diamond and graphite. While the DLC coatings show low friction and little wear, the tribological properties are improved by doping of silicon. Since the effect of the silicon on the improvement is not unveiled, we coated silicon wafers with Si-doped DLC (DLC-Si) films by direct-current plasma CVD process, evaluated their friction coefficient and wear depth, and investigated the cross-section profiles of the films. Ball-on-disk test revealed that the tribological properties improved most when silicon is added by 6-10 at.% against carbon in the DLC-Si films. X-ray reflectometry suggested the existence of a thin layer with a different scattering length density (SLD) on the surfaces of the DLC-Si films. The thickness of the layers is around 20 nm. Neutron reflectivity measurements confirmed the formation similar SLD structure, the composition and mass density of the films. It is concluded that the surface thin layers, which are not observed for a DLC film free from or without silicon, should be responsible for the enhanced tribological properties. (author)

  7. Effect of relative humidity on the tribological properties of hydrogenated diamond-like carbon films in a nitrogen environment

    International Nuclear Information System (INIS)

    Hydrogenated diamond-like carbon (DLC) films were deposited on Si (100) wafers by a plasma enhanced chemical vapour deposition technique using CH4 plus Ar as the feedstock. The friction and wear properties of the resulting films under different relative humidities, ranging from 5% to 100%, in a nitrogen environment, were measured using a ball-on-disc tribometer, with Si3N4 balls as the counterparts. The friction surfaces of the films and Si3N4 balls were observed on a scanning electron microscope, and investigated by x-ray photoelectron spectroscopy. The results showed that the friction coefficient increased continuously from 0.025 to 0.09 with increase in relative humidity from 5% to 100%, while the wear rate of the films sharply decreased and reached a minimum at a relative humidity of 40%, then it increased with further increase of the relative humidity. The interruption of the transferred carbon-rich layer on the Si3N4 ball, and the friction-induced oxidation of the films at higher relative humidity were proposed as the main reasons for the increase in the friction coefficient. Moreover, the oxidation and hydrolysis of the Si3N4 ball at higher relative humidity, leading to the formation of a tribochemical film, which mainly consists of silica gel, on the friction surface, are also thought to influence the friction and wear behaviour of the hydrogenated DLC films

  8. Debris reduction for copper and diamond-like carbon thin films produced by magnetically guided pulsed laser deposition

    CERN Document Server

    Tsui, Y Y; Vick, D; Fedosejevs, R

    2002-01-01

    The effectiveness of debris reduction using magnetically guided pulsed laser deposition (MGPLD) is reported here. KrF laser pulses (248 nm) of 100 mJ energy were focused to intensities of 6x10 sup 9 W/cm sup 2 onto the surface of a copper or a carbon source target and a magnetic field of 0.3 T as used to steer the plasma around a curved arc of 0.5 m length to the deposition substrate. Debris counts were compared for films produced by the MGPLD and conventional PLD (nonguided) techniques. A significant reduction in particulates of size greater than 0.1 mu m was achieved using MGPLD. For the copper films, particulate count was reduced from 150 000 particles/cm sup 2 /nm to 50 particulates/cm sup 2 /nm and for diamond-like carbon thin films particulate count was reduced from 25 000 particles/cm sup 2 /nm to 1200 particles/cm sup 2 /nm.

  9. Improved wear resistance of functional diamond like carbon coated Ti-6Al-4V alloys in an edge loading conditions.

    Science.gov (United States)

    Choudhury, Dipankar; Lackner, Jürgen M; Major, Lukasz; Morita, Takehiro; Sawae, Yoshinori; Bin Mamat, Azuddin; Stavness, Ian; Roy, Chanchal K; Krupka, Ivan

    2016-06-01

    This study investigates the durability of functional diamond-like carbon (DLC) coated titanium alloy (Ti-6Al-4V) under edge loading conditions for application in artificial hip joints. The multilayered (ML) functional DLC coatings consist of three key layers, each of these layers were designed for specific functions such as increasing fracture strength, adapting stress generation and enhancing wear resistance. A 'ball-on-disk' multi-directional wear tester was used in the durability test. Prior to the wear testing, surface hardness, modulus elasticity and Raman intensity were measured. The results revealed a significant wear reduction to the DLC coated Ti-6Al-4V disks compared to that of non-coated Ti-6Al-4V disks. Remarkably, the counterpart Silicon Nitride (Si3N4) balls also yielded lowered specific wear rate while rubbed against the coated disks. Hence, the pairing of a functional multilayered DLC and Si3N4 could be a potential candidate to orthopedics implants, which would perform a longer life-cycle against wear caused by edge loading. PMID:27085502

  10. Tribological investigation of diamond-like carbon coated micro-dimpled surface under bovine serum and osteoarthritis oriented synovial fluid

    Science.gov (United States)

    Ghosh, Subir; Choudhury, Dipankar; Roy, Taposh; Mamat, Azuddin Bin; Masjuki, H. H.; Pingguan-Murphy, Belinda

    2015-06-01

    Osteoarthritis-oriented synovial fluid (OASF), i.e., that typical of a patient with osteoarthritis, has different physical and biological characteristics than bovine serum (BS), a lubricant widely used in biotribological investigations. Micro-dimpled and diamond-like carbon- (DLC) coated surfaces are key emerging interfaces for orthopedic implants. In this study, tribological performances of dimpled surfaces, with and without DLC coating, have been investigated under both BS and OASF. The friction tests were performed utilizing a pin on a disk tribometer, whereas contact pressure, speed, and temperature were simulated to a ‘medium walking gait’ of hip joint conditions. The mechanical properties of the specimen and the physical properties of the lubricant were characterized before the friction test. Raman analysis was conducted to identify the coating condition both before and after the test. The DLC-coated dimpled surface showed maximum hardness and residual stress. A DLC-coated dimpled surface under an OASF lubricated condition yielded a lower friction coefficient and wear compared to those of plain and dimpled specimens. The higher graphitization of coated materials with increasing load was confirmed by Raman spectroscopy.

  11. Deposition and field-emission characterization of electrically conductive nitrogen-doped diamond-like amorphous carbon films

    International Nuclear Information System (INIS)

    For the fabrication of high performance field emitters, diamond-like amorphous carbon films doped with nitrogen (DAC:N) were formed using an intermittent supermagnetron plasma chemical vapor deposition technique. DAC:N films were deposited using isobutane plasma to investigate the influence of discharge-off time and electrode spacing on the physical properties of the films at upper- and lower-electrode radio frequency (rf) powers (LORF) of 800 W/50-800 W. At LORF of 100 W, a discharge-on time of 1 min, and a discharge-off time (cooling time) of 30 s-10 min, resistivity was decreased with a decrease of the cooling time. By reducing the electrode spacing from 60 to 20 mm at a LORF of 50 and 800 W, the optical band gap of DAC:N film was decreased from 0.85 and 0.23 eV to 0.6 and 0 eV, respectively. A flat DAC:N film of 700 A thickness was deposited on a n-Si wafer at rf powers of 800 W/800 W. Using this flat DAC:N film, a threshold electric field of 18 V/μm was observed and maximum field-emission current density of 2.2 mA/cm2 was observed at the electric field of 32 V/μm

  12. Physical properties of nitrogen-doped diamond-like amorphous carbon films deposited by supermagnetron plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Diamond-like amorphous carbon films doped with nitrogen (DAC:N) were deposited on Si and glass wafers intermittently using i-C4H10/N2 repetitive supermagnetron plasma chemical vapor deposition. Deposition duration, which is equal to a plasma heating time of wafer, was selected to be 40 or 60 s, and several layers were deposited repetitively to form one thick film. DAC:N films were deposited at a lower-electrode temperature of 100 deg. C as a function of upper- and lower-electrode rf powers (200 W/200 W-1 kW/1 kW) and N2 concentration (0%-80%). With an increase in N2 concentration and rf power, the resistivity and the optical band gap decreased monotonously. With increase of the deposition duration from 40 to 60 s, resistivity decreased to 0.03Ω cm and optical band gap decreased to 0.02 eV (substantially equal to 0 eV within the range of experimental error), at an N2 concentration of 80% and rf power of 1 kW(/1 kW)

  13. Tribological behaviors of diamond-like carbon coatings on plasma nitrided steel using three BN-containing lubricants

    Energy Technology Data Exchange (ETDEWEB)

    Jia Zhengfeng [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 73000 (China); College of Materials Science and Engineering, Liaocheng University, Liaocheng 252059 (China); Graduate School of the Chinese Academy of Sciences, Beijing 10039 (China); Wang Peng [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 73000 (China); Xia Yanqiu, E-mail: xiayanqiu@yahoo.com [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 73000 (China); Zhang Haobo; Pang Xianjuan [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 73000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 10039 (China); Li Bin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 73000 (China)

    2009-04-15

    In this work, diamond-like carbon (DLC) coatings were deposited on plasma nitrided AISI 1045 steel by magnetron sputtering. Three BN-containing additives and molybdenum dithiocarbamate (MoDTC) were added to poly-alpha-olefin (PAO) as additives. The additive content (mass fraction) in PAO was fixed at 0.5 wt%. The friction and wear characters of DLC coatings on nitrided steel discs sliding against AISI 52100 steel balls were tested under the lubricated conditions. It was found that borate esters have a higher load carrying capacity and much better anti-wear and friction-reducing ability than that of MoDTC. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were employed to explore the properties of the worn surface and the mechanism of friction and wear. According to the XPS analysis, the adsorbed organic N-containing compounds and BN are, possibly, the primary reason for the novel borate esters to possess a relatively constant coefficient of friction and lower wear rate. On the other hand, possibly, the MoDTC molecules break down during sliding and produce many Mo-oxides, and then the Mo-oxides destroy the DLC coating because of its sharp edge crystalline solid structure. After destroying the DLC coating, the MoDTC react with metals and form MoS{sub 2} tribofilm, and decrease coefficient of friction of rubbing pairs.

  14. In vitro and in vivo investigations into the biocompatibility of diamond-like carbon (DLC) coatings for orthopedic applications.

    Science.gov (United States)

    Allen, M; Myer, B; Rushton, N

    2001-05-01

    Diamond-like carbon (DLC) shows great promise as a durable, wear- and corrosion-resistant coating for biomedical implants. The effects of DLC coatings on the musculoskeletal system have not been investigated in detail. In this study, DLC coatings were deposited on polystyrene 24-well tissue culture plates by fast-atom bombardment from a hexane precursor. Two osteoblast-like cell lines were cultured on uncoated and DLC-coated plates for periods of up to 72 h. The effects of DLC coatings on cellular metabolism were investigated by measuring the production of three osteoblast-specific marker proteins: alkaline phosphatase, osteocalcin, and type I collagen. There was no evidence that the presence of the DLC coating had any adverse effect on any of the parameters measured in this study. In a second series of experiments, DLC-coated cobalt-chromium cylinders were implanted in intramuscular locations in rats and in transcortical sites in sheep. Histologic analysis of specimens retrieved 90 days after surgery showed that the DLC-coated specimens were well tolerated in both sites. These data indicate that DLC coatings are biocompatible in vitro and in vivo, and further investigations into their long-term biological and tribological performance are now warranted. PMID:11319748

  15. Wetting behavior and nanotribological properties of silicon nanopatterns combined with diamond-like carbon and perfluoropolyether films

    International Nuclear Information System (INIS)

    A large number of silicon (Si) patterns consisting of nanopillars of varying diameter and pitch have been fabricated and further coated with diamond-like carbon (DLC) and perfluoropolyether (Z-DOL) films. The wetting behavior and nano-adhesion/friction of the patterns are investigated experimentally in relation to the nanostructures and the hydrophobicity of the materials. Measurements of water contact angle illustrate that the patterning-enhanced wettability of the Si flat surface, along with two distinct wettings which are in good agreement with the Wenzel and hemi-wicking states, depended on the value of the pitch-over-diameter ratio. In the case of the coated patterns, three wetting states are observed: the Cassie-Baxter, the Wenzel, and a transition from the Cassie-Baxter into the Wenzel, which varies with regard to the hydrophobic properties of the DLC and Z-DOL. In terms of tribological properties, it is demonstrated that a combination of the nanopatterns and the films is effective in reducing adhesive and frictional forces. In addition, the pitch and diameter of the patterns are found to significantly influence their adhesion/friction behaviors.

  16. Wetting behavior and nanotribological properties of silicon nanopatterns combined with diamond-like carbon and perfluoropolyether films

    Science.gov (United States)

    Pham, D. C.; Na, K.; Piao, S.; Cho, I.-J.; Jhang, K.-Y.; Yoon, E.-S.

    2011-09-01

    A large number of silicon (Si) patterns consisting of nanopillars of varying diameter and pitch have been fabricated and further coated with diamond-like carbon (DLC) and perfluoropolyether (Z-DOL) films. The wetting behavior and nano-adhesion/friction of the patterns are investigated experimentally in relation to the nanostructures and the hydrophobicity of the materials. Measurements of water contact angle illustrate that the patterning-enhanced wettability of the Si flat surface, along with two distinct wettings which are in good agreement with the Wenzel and hemi-wicking states, depended on the value of the pitch-over-diameter ratio. In the case of the coated patterns, three wetting states are observed: the Cassie-Baxter, the Wenzel, and a transition from the Cassie-Baxter into the Wenzel, which varies with regard to the hydrophobic properties of the DLC and Z-DOL. In terms of tribological properties, it is demonstrated that a combination of the nanopatterns and the films is effective in reducing adhesive and frictional forces. In addition, the pitch and diameter of the patterns are found to significantly influence their adhesion/friction behaviors.

  17. Tribological behavior of diamond-like carbon film with different tribo-pairs: A size effect study

    International Nuclear Information System (INIS)

    A friction force microscope (FFM) with different probes and a ball-on-disk (BOD) tribo-meter were used to investigate the tribological properties of diamond-like carbon (DLC) films. DLC films were prepared by chemical vapor deposition (CVD) method by altering the deposition parameters, and their morphologies and structural information were examined with an atomic force microscope (AFM) and the Raman spectrum. The wear traces of the DLC films after frictional tests were analyzed by an optical microscope. It is found that surface roughness and adhesion play important roles in characterizing the tribological properties of DLC films using FFM. Moreover, the debris accumulation is another significant factor affecting the frictional behavior of DLC films, especially for the sharp tip. The difference in coefficients of friction (COFs) obtained by the BOD method among different DLC films under water lubrication is much smaller than the case without water lubrication. The variation trends in COF for the flat tip and the BOD test are similar in comparison with the result obtained with the sharp tip. The wear traces after frictional tests suggest that DLC films under water lubrication are prone to be damaged more readily

  18. Tribological behaviors of diamond-like carbon coatings on plasma nitrided steel using three BN-containing lubricants

    Science.gov (United States)

    Jia, Zheng-feng; Wang, Peng; Xia, Yan-qiu; Zhang, Hao-bo; Pang, Xian-juan; Li, Bin

    2009-04-01

    In this work, diamond-like carbon (DLC) coatings were deposited on plasma nitrided AISI 1045 steel by magnetron sputtering. Three BN-containing additives and molybdenum dithiocarbamate (MoDTC) were added to poly-alpha-olefin (PAO) as additives. The additive content (mass fraction) in PAO was fixed at 0.5 wt%. The friction and wear characters of DLC coatings on nitrided steel discs sliding against AISI 52100 steel balls were tested under the lubricated conditions. It was found that borate esters have a higher load carrying capacity and much better anti-wear and friction-reducing ability than that of MoDTC. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were employed to explore the properties of the worn surface and the mechanism of friction and wear. According to the XPS analysis, the adsorbed organic N-containing compounds and BN are, possibly, the primary reason for the novel borate esters to possess a relatively constant coefficient of friction and lower wear rate. On the other hand, possibly, the MoDTC molecules break down during sliding and produce many Mo-oxides, and then the Mo-oxides destroy the DLC coating because of its sharp edge crystalline solid structure. After destroying the DLC coating, the MoDTC react with metals and form MoS 2 tribofilm, and decrease coefficient of friction of rubbing pairs.

  19. Tribological behaviors of diamond-like carbon coatings on plasma nitrided steel using three BN-containing lubricants

    International Nuclear Information System (INIS)

    In this work, diamond-like carbon (DLC) coatings were deposited on plasma nitrided AISI 1045 steel by magnetron sputtering. Three BN-containing additives and molybdenum dithiocarbamate (MoDTC) were added to poly-alpha-olefin (PAO) as additives. The additive content (mass fraction) in PAO was fixed at 0.5 wt%. The friction and wear characters of DLC coatings on nitrided steel discs sliding against AISI 52100 steel balls were tested under the lubricated conditions. It was found that borate esters have a higher load carrying capacity and much better anti-wear and friction-reducing ability than that of MoDTC. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were employed to explore the properties of the worn surface and the mechanism of friction and wear. According to the XPS analysis, the adsorbed organic N-containing compounds and BN are, possibly, the primary reason for the novel borate esters to possess a relatively constant coefficient of friction and lower wear rate. On the other hand, possibly, the MoDTC molecules break down during sliding and produce many Mo-oxides, and then the Mo-oxides destroy the DLC coating because of its sharp edge crystalline solid structure. After destroying the DLC coating, the MoDTC react with metals and form MoS2 tribofilm, and decrease coefficient of friction of rubbing pairs.

  20. Friction and wear performance of diamond-like carbon, boron carbide, and titanium carbide coatings against glass

    International Nuclear Information System (INIS)

    Protection of glass substrates by direct ion beam deposited diamond-like carbon (DLC) coatings was observed using a commercial pin-on-disk instrument at ambient conditions without lubrication. Ion beam sputter-deposited titanium carbide and boron carbide coatings reduced sliding friction, and provided tribological protection of silicon substrates, but the improvement factor was less than that found for DLC. Observations of unlubricated sliding of hemispherical glass pins at ambient conditions on uncoated glass and silicon substrates, and ion beam deposited coatings showed decreased wear in the order: uncoated glass>uncoated silicon>boron carbide>titanium carbide>DLC>uncoated sapphire. Failure mechanisms varied widely and are discussed. Generally, the amount of wear decreased as the sliding friction decreased, with the exception of uncoated sapphire substrates, for which the wear was low despite very high friction. There is clear evidence that DLC coatings continue to protect the underlying substrate long after the damage first penetrates through the coating. The test results correlate with field use data on commercial products which have shown that the DLC coatings provide substantial extension of the useful lifetime of glass and other substrates. copyright 1997 Materials Research Society

  1. Comparative surface and nano-tribological characteristics of nanocomposite diamond-like carbon thin films doped by silver

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Han-Shen; Endrino, Jose L.; Anders, Andre

    2008-07-10

    In this study we have deposited silver-containing hydrogenated and hydrogen-free diamond-like carbon (DLC) nanocomposite thin films by plasma immersion ion implantation-deposition methods. The surface and nano-tribological characteristics were studied by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and nano-scratching experiments. The silver doping was found to have no measurable effect on sp2-sp3 hybridization of the hydrogenated DLC matrix and only a slight effect on the hydrogen-free DLC matrix. The surface topography was analyzed by surface imaging. High- and low-order roughness determined by AFM characterization was correlated to the DLC growth mechanism and revealed the smoothing effect of silver. The nano-tribological characteristics were explained in terms of friction mechanisms and mechanical properties in correlation to the surface characteristics. It was discovered that the adhesion friction was the dominant friction mechanism; the adhesion force between the scratching tip and DLC surface was decreased by hydrogenation and increased by silver doping.

  2. The Improvement of Tribological and Fatigue Properties of Casting Magnesium Alloy AZ91 Performed Diamond Like Carbon Coating

    Science.gov (United States)

    Akebono, Hiroyuki; Suzuki, Hideto

    In recent years, magnesium alloy has been widely used because of its low weight and ease of recycling. However, because magnesium alloys provide inferior wear resistance, it is necessary to improve this property to use magnesium alloy for more machine parts. For this study, we produced a diamond like carbon (DLC) coating that has high hardness, low friction, and excellent wear resistance. With DLC coated onto a soft material such as magnesium alloy, the adhesion strength between the substrate and the coating poses an important problem. Therefore, in this study, to acquire high adhesion strength, the DLC coating process was performed using unbalanced magnetron sputtering (UBMS). A tungsten-doped inter-layer was formed on the substrate. Onto the inter-layer, nano-order DLC coatings of two kinds were laminated. Wear tests and fatigue tests were carried out. The DLC-coated magnesium alloy exhibited excellent wear friction. Furthermore, DLC coatings raised its fatigue reliability over that of the substrate alone.

  3. Effects of molybdenum dithiocarbamate and zinc dialkyl dithiophosphate additives on tribological behaviors of hydrogenated diamond-like carbon coatings

    International Nuclear Information System (INIS)

    Highlights: • For MoDTC, DLC coating showed better anti-friction and worse anti-wear behaviors. • The improved anti-friction property was due to graphitization and MoS2. • Formation of MoOx resulted in a high wear volume. • For ZDDP, DLC coating showed the best anti-wear and the worst anti-friction behaviors. • Absence of friction reducing product and graphitized layer resulted in a higher friction. - Abstract: The tribological behaviors of hydrogenated diamond-like carbon (DLC) coatings under varied load conditions lubricated with polyalpha olefin (PAO), molybdenum dithiocarbamate (MoDTC) and zinc dialkyl dithiophosphate (ZDDP) additives were investigated in this paper. Hydrogenated DLC coatings were synthesized through the decomposition of acetylene by the ion source. The tribological performances were measured on a SRV tribometer. The morphologies and chemical structures of the DLC coatings were investigated by the scanning electron microscope (SEM), Raman spectrometer (Raman) and X-ray photoelectron spectroscope (XPS). It was shown that the low friction and high wear were achieved on the hydrogenated DLC coating under MoDTC lubrication, while low wear was found on the hydrogenated DLC coating lubricated by ZDDP. The primary reason was attributed to different tribofilms formed on the contact area and the formation of graphitic layer. Both factors working together leaded to quite different tribological behaviors

  4. Comparative study of the tribological behavior under hybrid lubrication of diamond-like carbon films with different adhesion interfaces

    Science.gov (United States)

    Costa, R. P. C.; Lima-Oliveira, D. A.; Marciano, F. R.; Lobo, A. O.; Corat, E. J.; Trava-Airoldi, V. J.

    2013-11-01

    This paper reports the influence of the adhesion interlayer between stainless steel and diamond-like carbon (DLC) films in two different contact conditions: in dry air and deionized water. The water was the liquid used to understand the mechanism and chemical reactions of the tribolayer formation under boundary lubrication. The effect of silicon and carbonitride adhesion interlayer was investigated on uncoated and coated DLC films. The results show that DLC/DLC pairs using carbonitride in air (30% RH) showed 60% less friction coefficient and wear less than three orders of magnitude than DLC/DLC pairs using silicon as interlayer. In deionized water, DLC/DLC pairs using carbonitride as interlayer showed 31% less friction coefficient when compared to DLC/DLC pairs with silicon. Raman related the chemical and structural changes in the DLC films during sliding in air and in the presence of water. Scratch tests showed a critical load of 14 N and 33 N in DLC films with silicon and carbonitride, respectively.

  5. Functionalization of Hydrogen-free Diamond-like Carbon Films using Open-air Dielectric Barrier Discharge Atmospheric Plasma Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Instituto de Materiales de Madrid, C.S.I.C., Cantoblanco, 28049 Madrid, Spain; Instituto de Quimica-Fisica" Rocasolano" C.S.I.C., 28006 Madrid, Spain; Mahasarakham University, Mahasarakham 44150, Thailand; CASTI, CNR-INFM Regional Laboratory, L' Aquila 67100, Italy; SUNY Upstate Medical University, Syracuse, NY 13210, USA; Endrino, Jose; Endrino, J. L.; Marco, J. F.; Poolcharuansin, P.; Phani, A.R.; Allen, M.; Albella, J. M.; Anders, A.

    2007-12-28

    A dielectric barrier discharge (DBD) technique has been employed to produce uniform atmospheric plasmas of He and N2 gas mixtures in open air in order to functionalize the surface of filtered-arc deposited hydrogen-free diamond-like carbon (DLC) films. XPS measurements were carried out on both untreated and He/N2 DBD plasma treated DLC surfaces. Chemical states of the C 1s and N 1s peaks were collected and used to characterize the surface bonds. Contact angle measurements were also used to record the short- and long-term variations in wettability of treated and untreated DLC. In addition, cell viability tests were performed to determine the influence of various He/N2 atmospheric plasma treatments on the attachment of osteoblast MC3T3 cells. Current evidence shows the feasibility of atmospheric plasmas in producing long-lasting variations in the surface bonding and surface energy of hydrogen-free DLC and consequently the potential for this technique in the functionalization of DLC coated devices.

  6. Silver nanoparticle-enriched diamond-like carbon implant modification as a mammalian cell compatible surface with antimicrobial properties

    Science.gov (United States)

    Gorzelanny, Christian; Kmeth, Ralf; Obermeier, Andreas; Bauer, Alexander T.; Halter, Natalia; Kümpel, Katharina; Schneider, Matthias F.; Wixforth, Achim; Gollwitzer, Hans; Burgkart, Rainer; Stritzker, Bernd; Schneider, Stefan W.

    2016-03-01

    The implant-bone interface is the scene of competition between microorganisms and distinct types of tissue cells. In the past, various strategies have been followed to support bony integration and to prevent bacterial implant-associated infections. In the present study we investigated the biological properties of diamond-like carbon (DLC) surfaces containing silver nanoparticles. DLC is a promising material for the modification of medical implants providing high mechanical and chemical stability and a high degree of biocompatibility. DLC surface modifications with varying silver concentrations were generated on medical-grade titanium discs, using plasma immersion ion implantation-induced densification of silver nanoparticle-containing polyvinylpyrrolidone polymer solutions. Immersion of implants in aqueous liquids resulted in a rapid silver release reducing the growth of surface-bound and planktonic Staphylococcus aureus and Staphylococcus epidermidis. Due to the fast and transient release of silver ions from the modified implants, the surfaces became biocompatible, ensuring growth of mammalian cells. Human endothelial cells retained their cellular differentiation as indicated by the intracellular formation of Weibel-Palade bodies and a high responsiveness towards histamine. Our findings indicate that the integration of silver nanoparticles into DLC prevents bacterial colonization due to a fast initial release of silver ions, facilitating the growth of silver susceptible mammalian cells subsequently.

  7. Effects of nitrogen content on structure and electrical properties of nitrogen-doped fluorinated diamond-like carbon films

    Institute of Scientific and Technical Information of China (English)

    XIAO Jian-rong; LI Xin-hai; WANG Zhi-xing

    2009-01-01

    Nitrogen-doped fluorinated diamond-like carbon (FN-DLC) films were prepared on single crystal silicon substrate by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) under different deposited conditions with CF4,CH4 and nitrogen as source gases.The influence of nitrogen content on the structure and electrical properties of the films was studied.The films were investigated in terms of surface morphology,microstructure,chemical composition and electrical properties.Atomic force microscopy (AFM) results revealed that the surface morphology of the films became smooth due to doping nitrogen.Fourier transform infrared absorption spectrometry (FTIR) results showed that amouts of C=N and C≡N bonds increased gradually with increasing nitrogen partial pressure r (r=p(N_2)/p(N_2+CF_4+CH_4)).Gaussian fit results of C 1s and N 1s in X-ray photoelectron spectra (XPS) showed that the incorporation of nitrogen presented mainly in the forms of β-C_3N_4 and a-CN_x (x=1,2,3) in the films.The current-voltage (I-V) measurement results showed that the electrical conductivity of the films increased with increasing nitrogen content.

  8. Deep-drawing of aluminum sheets without lubricant by use of diamond-like carbon coated dies

    Energy Technology Data Exchange (ETDEWEB)

    Murakawa, M. [Nippon Inst. of Technol., Saitama (Japan). Dept. of Mech. Eng.; Koga, N. [Nippon Inst. of Technol., Saitama (Japan). Dept. of Mech. Eng.; Kumagai, T. [Nanotec Corporation, Saitama (Japan)

    1995-12-01

    In this article we propose the use of a diamond-like carbon (DLC) film coated onto the die in order to deep-draw aluminum sheets without lubricant. The use of a DLC coating has, surprisingly, been found to eliminate the need for any lubricant to prevent adhesion of aluminum to the die material during up to about 6200 deep-drawing operations in which square cups, each with a size of 20 x 20 x 12 (depth) mm, were produced. The DLC was coated onto a WC-Co alloy drawing die by means of an ion plating apparatus in which a tri-electrode-type DC arc discharge ion source with a hot filament, an anode and a reflector were used with a precursor of benzene. The work material was 1 mm thick A5000 aluminum sheet. In contrast to the DLC-coated die, an uncoated WC-Co alloy deep-drawing die operated without any lubricant caused fracture of the aluminum sheet after only five repetitions of deep-drawing because of the strong adhesion of the material to the die. This demonstrates the dramatic effects of the DLC coating. (orig.)

  9. Extraordinary self-lubrication properties of non-hydrogenated diamond-like carbon films under humid atmosphere

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Tribological properties of non-hydrogenated diamond-like carbon (DLC) films were investigated under humid (RH=80%) and dry (RH=5%) air. These films were deposited by pulsed laser deposition (PLD) at different substrate temperatures. Tribological properties of DLC fabricated by PLD is not sensitive to the relative humidity of testing environment. Because of the unique growth mechanism of DLC pre- pared by PLD, DLC is of "soft-hard" double layers, having a very low friction coefficient and wear rate under humid atmosphere. The minimum coefficient and wear rate of film under humid circumstance are 0.045 and 5.94×10?10 mm3N-1m-1, respectively, just a little bit more than those under dry condition. The root means square roughness of film is less than 1 nm. The sp3 content of film grown at room tem- perature (RT) is 72%, and the sp3 content decreases with temperature. Raman spectrum shows that the micro-structure is amorphous network. The largest hardness and elastic modulus of film are 51 GPa and 350 GPa, respectively and they reduce with increase of deposition temperature too. Water contact angles on surface are more than 90° which indicates that films fabricated by PLD are hydrophobic with low surface energy.

  10. Fluorine and boron co-doped diamond-like carbon films deposited by pulsed glow discharge plasma immersion ion processing

    CERN Document Server

    He, X M; Peters, A M; Taylor, B; Nastasi, M

    2002-01-01

    Fluorine (F) and boron (B) co-doped diamond-like carbon (FB-DLC) films were prepared on different substrates by the plasma immersion ion processing (PIIP) technique. A pulse glow discharge plasma was used for the PIIP deposition and was produced at a pressure of 1.33 Pa from acetylene (C sub 2 H sub 2), diborane (B sub 2 H sub 6), and hexafluoroethane (C sub 2 F sub 6) gas. Films of FB-DLC were deposited with different chemical compositions by varying the flow ratios of the C sub 2 H sub 2 , B sub 2 H sub 6 , and C sub 2 F sub 6 source gases. The incorporation of B sub 2 H sub 6 and C sub 2 F sub 6 into PIIP deposited DLC resulted in the formation of F-C and B-C hybridized bonding structures. The levels of the F and B concentrations effected the chemical bonding and the physical properties as was evident from the changes observed in density, hardness, stress, friction coefficient, and contact angle of water on films. Compared to B-doped or F-doped DLC films, the F and B co-doping of DLC during PIIP deposition...

  11. Influence of Hydrogen Content on Optical and Mechanical Performances of Diamond-Like Carbon Films on Glass Substrate

    Science.gov (United States)

    Sun, Yao; Huang, Xing-Ye; Wang, Hong

    2016-04-01

    The protective layer for cover glass of touch panel screen for electronic mobile devices is required to have good mechanical properties and decent optical transparency simultaneously. The hydrogenated diamond-like carbon (a-C:H) films were deposited on glass substrate by RF-PECVD in the negative stage potential mode (NP mode), as well as the ground stage potential mode (GP mode). The impact of hydrogen content, affected by stage potential and RF power, on optical and mechanical properties was investigated. The results show that hydrogen content decreases with increasing RF power, due to the dehydrogenation effect. Higher hydrogen content in films results in lower refractive index, lower extinction coefficient, lower optical absorptions, larger optical band gap and higher transmittance, but lower hardness and wearing resistance. Therefore, although the GP mode DLC is optically favorable because of higher hydrogen content, the NP mode one is far more superior from mechanical standpoint. A compromise can be reached to deposit an ultrathin layer of DLC in NP mode, which offers a good combination of properties to meet the requirement for the protective layer of cover glass.

  12. Antimicrobial Properties of Diamond-Like Carbon/Silver Nanocomposite Thin Films Deposited on Textiles: Towards Smart Bandages

    Directory of Open Access Journals (Sweden)

    Tadas Juknius

    2016-05-01

    Full Text Available In the current work, a new antibacterial bandage was proposed where diamond-like carbon with silver nanoparticle (DLC:Ag-coated synthetic silk tissue was used as a building block. The DLC:Ag structure, the dimensions of nanoparticles, the silver concentration and the silver ion release were studied systematically employing scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic absorption spectroscopy, respectively. Antimicrobial properties were investigated using microbiological tests (disk diffusion method and spread-plate technique. The DLC:Ag layer was stabilized on the surface of the bandage using a thin layer of medical grade gelatin and cellulose. Four different strains of Staphylococcus aureus extracted from humans’ and animals’ infected wounds were used. It is demonstrated that the efficiency of the Ag+ ion release to the aqueous media can be increased by further RF oxygen plasma etching of the nanocomposite. It was obtained that the best antibacterial properties were demonstrated by the plasma-processed DLC:Ag layer having a 3.12 at % Ag surface concentration with the dominating linear dimensions of nanoparticles being 23.7 nm. An extra protective layer made from cellulose and gelatin with agar contributed to the accumulation and efficient release of silver ions to the aqueous media, increasing bandage antimicrobial efficiency up to 50% as compared to the single DLC:Ag layer on textile.

  13. Tribological behavior of diamond-like carbon film with different tribo-pairs: A size effect study

    Science.gov (United States)

    Xie, Guoxin; Zheng, Beirong; Li, Wei; Xue, Wei

    2008-08-01

    A friction force microscope (FFM) with different probes and a ball-on-disk (BOD) tribo-meter were used to investigate the tribological properties of diamond-like carbon (DLC) films. DLC films were prepared by chemical vapor deposition (CVD) method by altering the deposition parameters, and their morphologies and structural information were examined with an atomic force microscope (AFM) and the Raman spectrum. The wear traces of the DLC films after frictional tests were analyzed by an optical microscope. It is found that surface roughness and adhesion play important roles in characterizing the tribological properties of DLC films using FFM. Moreover, the debris accumulation is another significant factor affecting the frictional behavior of DLC films, especially for the sharp tip. The difference in coefficients of friction (COFs) obtained by the BOD method among different DLC films under water lubrication is much smaller than the case without water lubrication. The variation trends in COF for the flat tip and the BOD test are similar in comparison with the result obtained with the sharp tip. The wear traces after frictional tests suggest that DLC films under water lubrication are prone to be damaged more readily.

  14. Silver nanoparticle-enriched diamond-like carbon implant modification as a mammalian cell compatible surface with antimicrobial properties

    Science.gov (United States)

    Gorzelanny, Christian; Kmeth, Ralf; Obermeier, Andreas; Bauer, Alexander T.; Halter, Natalia; Kümpel, Katharina; Schneider, Matthias F.; Wixforth, Achim; Gollwitzer, Hans; Burgkart, Rainer; Stritzker, Bernd; Schneider, Stefan W.

    2016-01-01

    The implant-bone interface is the scene of competition between microorganisms and distinct types of tissue cells. In the past, various strategies have been followed to support bony integration and to prevent bacterial implant-associated infections. In the present study we investigated the biological properties of diamond-like carbon (DLC) surfaces containing silver nanoparticles. DLC is a promising material for the modification of medical implants providing high mechanical and chemical stability and a high degree of biocompatibility. DLC surface modifications with varying silver concentrations were generated on medical-grade titanium discs, using plasma immersion ion implantation-induced densification of silver nanoparticle-containing polyvinylpyrrolidone polymer solutions. Immersion of implants in aqueous liquids resulted in a rapid silver release reducing the growth of surface-bound and planktonic Staphylococcus aureus and Staphylococcus epidermidis. Due to the fast and transient release of silver ions from the modified implants, the surfaces became biocompatible, ensuring growth of mammalian cells. Human endothelial cells retained their cellular differentiation as indicated by the intracellular formation of Weibel-Palade bodies and a high responsiveness towards histamine. Our findings indicate that the integration of silver nanoparticles into DLC prevents bacterial colonization due to a fast initial release of silver ions, facilitating the growth of silver susceptible mammalian cells subsequently. PMID:26955791

  15. Substrate and material transfer effects on the surface chemistry and texture of diamond-like carbon deposited by plasma-enhanced chemical vapour deposition

    OpenAIRE

    Jones, Benjamin; Ojeda, J. J.

    2012-01-01

    Diamond-like carbon (DLC), a thin amorphous carbon film, has many uses in tribological systems. Exploiting alternative substrates and interlayers can enable the control of the hardness and modulus of the multilayer system and improve wear or friction properties. We used XPS and atomic force microscopy to examine DLC that had been concurrently coated on an epoxy interlayer and a steel substrate by plasma-enhanced chemical vapour deposition. sp2/sp3 ratios were calculated both by the deconvolut...

  16. Studies of diamond-like carbon (DLC) films deposited on stainless steel substrate with Si/SiC intermediate layers

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Liu Gui-Chang; Wang Li-Da; Deng Xin-Lü; Xu Jun

    2008-01-01

    In this work, diamond-like carbon (DLC) films were deposited on stainless steel substrates with Si/SiC intermediate layers by combining plasma enhanced sputtering physical vapour deposition (PEUMS-PVD) and microwave electron cyclotron resonance plasma enhanced chemical vapour deposition (MW-ECRPECVD) techniques. The influence of substrate negative self-bias voltage and Si target power on the structure and nano-mechanical behaviour of the DLC films were investigated by Raman spectroscopy, nano-indentation, and the film structural morphology by atomic force microscopy (AFM). With the increase of deposition bias voltage, the G band shifted to higher wave-number and the integrated intensity ratio ID/IG increased. We considered these as evidences for the development of graphitization in the films. As the substrate negative self-bias voltage increased, particle bombardment function was enhanced and thesp3-bond carbon density reducing, resulted in the peak values of hardness (H) and elastic modulus (E). Silicon addition promoted the formation of sp3 bonding and reduced the hardness. The incorporated Si atoms substituted sp2- bond carbon atoms in ring structures, which promoted the formation of sp3-bond. The structural transition from C-C to C-Si bonds resulted in relaxation of the residual stress which led to the decrease of internal stress and hardness. The results of AFM indicated that the films was dense and homogeneous, the roughness of the films was decreased due to the increase of substrate negative self-bias voltage and the Si target power.

  17. Optical and interfacial electronic properties of diamond-like carbon films

    Science.gov (United States)

    Woollam, J. A.; Natarajan, V.; Lamb, J.; Khan, A. A.; Bu-Abbud, G.; Banks, B.; Pouch, J.; Gulino, D. A.; Domitz, S.; Liu, D. C.

    1984-01-01

    Hard, semitransparent carbon films were prepared on oriented polished crystal wafers of silicon, indium phosphide and gallium arsenide, as well as on KBr and quartz. Properties of the films were determined using IR and visible absorption spectrocopy, ellipsometry, conductance-capacitance spectroscopy and alpha particle-proton recoil spectroscopy. Preparation techniques include RF plasma decomposition of methane (and other hydrocarbons), ion beam sputtering, and dual-ion-beam sputter deposition. Optical energy band gaps as large as 2.7 eV and extinction coefficients lower than 0.1 at long wavelengths are found. Electronic state densities at the interface with silicon as low as 10 to the 10th states/eV sq cm per were found.

  18. [The possibilities for the application of the fluoroplast-based prostheses with a diamond-like carbon nanocoating in ear surgery (an experimental study)].

    Science.gov (United States)

    Sitnikov, V P; Shil'ko, S V; Khusam, Él'-Refaĭ; Nadyrov, É A; Kazachenko, V P; Dzhaĭnakbaev, N T

    2014-01-01

    The objective of the present study was to elucidate general and local characteristics of the tissue reactions to the implantation of radiation-modified polytetrafluoroethylene (PTFE)-based fluoroplast F-4PM20 with a diamond-like carbon (DLC) nanocoating or with the diamond-like carbon coating containing the dispersed nano-sized silver particles to the experimental animals (rats). A total of 150 inbred white rats were included into the experiment; they were divided into 3 groups comprised of 50 animals each. The rats in group 1 were implanted with the 5 nm thick strips of fluoroplast F-4PM20 having the diamond-like carbon nanocoating. The animals of group 2 were implanted with the same material containing nanoparticles of chemically pure silver dispersed in the coating, those in group 3 (controls) were implanted with the fluoroplast F-4PM20 without a coating. The animals were sacrificed on days 7, 21, 30, and 60 days after the onset of the experiment. The tissues surrounding the implant as well as heart, lung, spleen, liver, and kidney tissues were taken for the histological study. The local reactions of different tissues were found to be uniform even though there was an apparent tendency toward the less pronounced granulation and scarification processes in the animals implanted with the diamond-like carbon coating containing the dispersed nano-sized silver particles. In none of the groups, the animals exhibited statistically significant lymphoid tissue hyperplasia in the spleen which suggested the activation of the immune system in response to implantation. It is concluded that the PTFE-based fluoroplast F-4PM20 implants with the 5 nm thick DLC coating and a similar coating containing the dispersed nano-sized silver particles can be applied for middle ear reconstructive surgery, being a histologically compatible material that does not cause an inflammatory degenerative response of the tissues. PMID:25246203

  19. Wear resistance of thick diamond like carbon coatings against polymeric materials used in single screw plasticizing technology

    Science.gov (United States)

    Zitzenbacher, G.; Liu, K.; Forsich, C.; Heim, D.

    2015-05-01

    Wear on the screw and barrel surface accompany polymer single screw plasticizing technology from the beginning. In general, wear on screws can be reduced by using nitrided steel surfaces, fused armour alloys on the screw flights and coatings. However, DLC-coatings (Diamond Like Carbon) comprise a number of interesting properties such as a high hardness, a low coefficient of friction and an excellent corrosion resistance due to their amorphous structure. The wear resistance of about 50 µm thick DLC-coatings against polyamide 6.6, polybutylene terephthalate and polypropylene is investigated in this paper. The tribology in the solids conveying zone of a single screw extruder until the beginning of melting is evaluated using a pin on disc tribometer and a so called screw tribometer. The polymeric pins are pressed against coated metal samples using the pin on disc tribometer and the tests are carried out at a defined normal force and sliding velocity. The screw tribometer is used to perform tribological experiments between polymer pellets and rotating coated metal shafts simulating the extruder screw. Long term experiments were performed to evaluate the wear resistance of the DLC-coating. A reduction of the coefficient of friction can be observed after a frictional distance of about 20 kilometers using glass fibre reinforced polymeric materials. This reduction is independent on the polymer and accompanied by a black layer on the wear surface of the polymeric pins. The DLC-coated metal samples show an up to 16 µm deep wear track after the 100 kilometer test period against the glass fiber filled materials only.

  20. On Interlayer Stability and High-Cycle Simulator Performance of Diamond-Like Carbon Layers for Articulating Joint Replacements

    Directory of Open Access Journals (Sweden)

    Kerstin Thorwarth

    2014-06-01

    Full Text Available Diamond like carbon (DLC coatings have been proven to be an excellent choice for wear reduction in many technical applications. However, for successful adaption to the orthopaedic field, layer performance, stability and adhesion in physiologically relevant setups are crucial and not consistently investigated. In vitro wear testing as well as adequate corrosion tests of interfaces and interlayers are of great importance to verify the long term stability of DLC coated load bearing implants in the human body. DLC coatings were deposited on articulating lumbar spinal disks made of CoCr28Mo6 biomedical implant alloy using a plasma-activated chemical vapor deposition (PACVD process. As an adhesion promoting interlayer, tantalum films were deposited by magnetron sputtering. Wear tests of coated and uncoated implants were performed in physiological solution up to a maximum of 101 million articulation cycles with an amplitude of ±2° and −3/+6° in successive intervals at a preload of 1200 N. The implants were characterized by gravimetry, inductively coupled plasma optical emission spectrometry (ICP-OES and cross section scanning electron microscopy (SEM analysis. It is shown that DLC coated surfaces with uncontaminated tantalum interlayers perform very well and no corrosive or mechanical failure could be observed. This also holds true in tests featuring overload and third-body wear by cortical bone chips present in the bearing pairs. Regarding the interlayer tolerance towards interlayer contamination (oxygen, limits for initiation of potential failure modes were established. It was found that mechanical failure is the most critical aspect and this mode is hypothetically linked to the α-β tantalum phase switch induced by increasing oxygen levels as observed by X-ray diffraction (XRD. It is concluded that DLC coatings are a feasible candidate for near zero wear articulations on implants, potentially even surpassing the performance of ceramic vs

  1. Atomic force microscopy and tribology study of the adsorption of alcohols on diamond-like carbon coatings and steel

    International Nuclear Information System (INIS)

    Polar molecules are known to affect the friction and wear of steel contacts via adsorption onto the surface, which represents one of the fundamental boundary-lubrication mechanisms. Since the basic chemical and physical effects of polar molecules on diamond-like carbon (DLC) coatings have been investigated only very rarely, it is important to find out whether such molecules have a similar effect on DLC coatings as they do on steel. In our study the adsorption of hexadecanol in various concentrations (2–20 mmol/l) on DLC was studied under static conditions using an atomic force microscope (AFM). The amount of surface coverage, the size and the density of the adsorbed islands of alcohol molecules were analyzed. Tribological tests were also performed to correlate the wear and friction behaviours with the adsorption of molecules on the surface. In this case, steel surfaces served as a reference. The AFM was successfully used to analyze the adsorption ability of polar molecules onto the DLC surfaces and a good correlation between the AFM results and the tribological behaviour of the DLC and the steel was found. We confirmed that alcohols can adsorb physically and chemically onto the DLC surfaces and are, therefore, potential boundary-lubrication agents for the DLC coatings. The adsorption of alcohol onto the DLC surfaces reduces the wear of the coatings, but it is less effective in reducing the friction because of the already inherently low-friction properties of DLC. Tentative adsorption mechanisms that include the environmental species effect, the temperature effect and the tribological rubbing effect are proposed for DLC and steel surfaces.

  2. Atomic force microscopy and tribology study of the adsorption of alcohols on diamond-like carbon coatings and steel

    Energy Technology Data Exchange (ETDEWEB)

    Kalin, M., E-mail: mitjan.kalin@tint.fs.uni-lj.si [University of Ljubljana, Faculty of Mechanical Engineering, Laboratory for Tribology and Interface Nanotechnology, Bogišićeva 8, 1000 Ljubljana (Slovenia); Simič, R. [University of Ljubljana, Faculty of Mechanical Engineering, Laboratory for Tribology and Interface Nanotechnology, Bogišićeva 8, 1000 Ljubljana (Slovenia)

    2013-04-15

    Polar molecules are known to affect the friction and wear of steel contacts via adsorption onto the surface, which represents one of the fundamental boundary-lubrication mechanisms. Since the basic chemical and physical effects of polar molecules on diamond-like carbon (DLC) coatings have been investigated only very rarely, it is important to find out whether such molecules have a similar effect on DLC coatings as they do on steel. In our study the adsorption of hexadecanol in various concentrations (2–20 mmol/l) on DLC was studied under static conditions using an atomic force microscope (AFM). The amount of surface coverage, the size and the density of the adsorbed islands of alcohol molecules were analyzed. Tribological tests were also performed to correlate the wear and friction behaviours with the adsorption of molecules on the surface. In this case, steel surfaces served as a reference. The AFM was successfully used to analyze the adsorption ability of polar molecules onto the DLC surfaces and a good correlation between the AFM results and the tribological behaviour of the DLC and the steel was found. We confirmed that alcohols can adsorb physically and chemically onto the DLC surfaces and are, therefore, potential boundary-lubrication agents for the DLC coatings. The adsorption of alcohol onto the DLC surfaces reduces the wear of the coatings, but it is less effective in reducing the friction because of the already inherently low-friction properties of DLC. Tentative adsorption mechanisms that include the environmental species effect, the temperature effect and the tribological rubbing effect are proposed for DLC and steel surfaces.

  3. Atomic force microscopy and tribology study of the adsorption of alcohols on diamond-like carbon coatings and steel

    Science.gov (United States)

    Kalin, M.; Simič, R.

    2013-04-01

    Polar molecules are known to affect the friction and wear of steel contacts via adsorption onto the surface, which represents one of the fundamental boundary-lubrication mechanisms. Since the basic chemical and physical effects of polar molecules on diamond-like carbon (DLC) coatings have been investigated only very rarely, it is important to find out whether such molecules have a similar effect on DLC coatings as they do on steel. In our study the adsorption of hexadecanol in various concentrations (2-20 mmol/l) on DLC was studied under static conditions using an atomic force microscope (AFM). The amount of surface coverage, the size and the density of the adsorbed islands of alcohol molecules were analyzed. Tribological tests were also performed to correlate the wear and friction behaviours with the adsorption of molecules on the surface. In this case, steel surfaces served as a reference. The AFM was successfully used to analyze the adsorption ability of polar molecules onto the DLC surfaces and a good correlation between the AFM results and the tribological behaviour of the DLC and the steel was found. We confirmed that alcohols can adsorb physically and chemically onto the DLC surfaces and are, therefore, potential boundary-lubrication agents for the DLC coatings. The adsorption of alcohol onto the DLC surfaces reduces the wear of the coatings, but it is less effective in reducing the friction because of the already inherently low-friction properties of DLC. Tentative adsorption mechanisms that include the environmental species effect, the temperature effect and the tribological rubbing effect are proposed for DLC and steel surfaces.

  4. Cell adhesion and growth on ultrananocrystalline diamond and diamond-like carbon films after different surface modifications

    Energy Technology Data Exchange (ETDEWEB)

    Miksovsky, J. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Institute of Physics ASCR, Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Voss, A. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Kozarova, R. [Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia (Bulgaria); Kocourek, T.; Pisarik, P. [Institute of Physics ASCR, Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Ceccone, G. [Unit Nanobiosciences, European Commission Joint Research Centre, Ispra (Italy); Kulisch, W. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Jelinek, M. [Institute of Physics ASCR, Prague (Czech Republic); Czech Technical University in Prague, Faculty of Biomedical Engineering, Kladno (Czech Republic); Apostolova, M.D. [Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia (Bulgaria); Reithmaier, J.P. [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany); Popov, C., E-mail: popov@ina.uni-kassel.de [Institute of Nanostructure Technologies and Analytics, Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel (Germany)

    2014-04-01

    Graphical abstract: - Highlights: • UNCD and DLC films were modified by UV/O{sub 3} treatments, O{sub 2} or NH{sub 3}-containing plasmas. • Surface composition, wettability and surface energy change upon modifications. • Higher efficiency of UNCD modifications was observed. • Cell attachment and growth were influenced by the surface termination and roughness. - Abstract: Diamond and diamond-like carbon (DLC) films possess a set of excellent physical and chemical properties which together with a high biocompatibility make them attractive candidates for a number of medical and biotechnological applications. In the current work thin ultrananocrystalline diamond (UNCD) and DLC films were comparatively investigated with respect to cell attachment and proliferation after different surface modifications. The UNCD films were prepared by microwave plasma enhanced chemical vapor deposition, the DLC films by pulsed laser deposition (PLD). The films were comprehensively characterized with respect to their basic properties, e.g. crystallinity, morphology, chemical bonding nature, etc. Afterwards the UNCD and DLC films were modified applying O{sub 2} or NH{sub 3}/N{sub 2} plasmas and UV/O{sub 3} treatments to alter their surface termination. The surface composition of as-grown and modified samples was studied by X-ray photoelectron spectroscopy (XPS). Furthermore the films were characterized by contact angle measurements with water, formamide, 1-decanol and diiodomethane; from the results obtained the surface energy with its dispersive and polar components was calculated. The adhesion and proliferation of MG63 osteosarcoma cells on the different UNCD and DLC samples were assessed by measurement of the cell attachment efficiency and MTT assays. The determined cell densities were compared and correlated with the surface properties of as-deposited and modified UNCD and DLC films.

  5. In vitro Cyto and Blood Compatibility of Titanium Containing Diamond-Like Carbon Prepared by Hybrid Sputtering Method

    Institute of Scientific and Technical Information of China (English)

    Krishnasamy NAVANEETHA PANDIYARAJ; Jan HEEG; Andreas LAMPKA; Fabian JUNGE; Torsten BARFELS; Marion WIENECKE; Young Ha RHEE; Hyoung Woo KIM

    2012-01-01

    In recent years, diamond-like carbon films (DLC) have been given more attention in research in the biomedical industry due to their potential application as surface coating on biomedical materials such as metals and polymer substrates. There are many ways to prepare metal containing DLC films deposited on polymeric film substrates, such as coatings from car- bonaceous precursors and some means that incorporate other elements. In this study, we in- vestigated both the surface and biocompatible properties of titanium containing DLC (Ti-DLC) films. The Ti-DLC films were prepared on the surface of poly (ethylene terephthalate) (PET) film as a function of the deposition power level using reactive sputtering technique. The films' hydrophilicity was studied by contact angle and surface energy tests. Their surface morphology was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Their elemental chemical composition was analyzed using energy dispersive X-spectra (EDX) and X-ray photoelectron spectroscopy (XPS). Their blood and cell compatibility was studied by in vitro tests, including tests on platelet adhesion, thrombus formation, whole blood clotting time and osteoblast cell compatibility. Significant changes in the morphological and chemical composition of the Ti-DLC films were observed and found to be a function of the deposition level. These morphological and chemical changes reduced the interfacial tension between Ti-DLC and blood proteins as well as resisted the adhesion and activation of platelets on the surface of the Ti-DLC films. The cell compatibility results exhibited significant growth of osteoblast cells on the surface of Ti incorporated DLC film compared with that of DLC film surface.

  6. Diamond-like carbon coatings enhance the hardness and resilience of bearing surfaces for use in joint arthroplasty.

    Science.gov (United States)

    Roy, M E; Whiteside, L A; Xu, J; Katerberg, B J

    2010-04-01

    The purpose of this study was to evaluate the potential of a hard diamond-like carbon (DLC) coating to enhance the hardness and resilience of a bearing surface in joint replacement. The greater hardness of a magnesium-stabilized zirconium (Mg-PSZ) substrate was expected to provide a harder coating-substrate composite microhardness than the cobalt-chromium alloy (CoCr) also used in arthroplasty. Three femoral heads of each type (CoCr, Mg-PSZ, DLC-CoCr and DLC-Mg-PSZ) were examined. Baseline (non-coated) and composite coating/substrate hardness was measured by Vickers microhardness tests, while nanoindentation tests measured the hardness and elastic modulus of the DLC coating independent of the Mg-PSZ and CoCr substrates. Non-coated Mg-PSZ heads were considerably harder than non-coated CoCr heads, while DLC coating greatly increased the microhardness of the CoCr and Mg-PSZ substrates. On the nanoscale the non-coated heads were much harder than on the microscale, with CoCr exhibiting twice as much plastic deformation as Mg-PSZ. The mechanical properties of the DLC coatings were not significantly different for both the CoCr and Mg-PSZ substrates, producing similar moduli of resilience and plastic resistance ratios. DLC coatings greatly increased hardness on both the micro and nano levels and significantly improved resilience and resistance to plastic deformation compared with non-coated heads. Because Mg-PSZ allows less plastic deformation than CoCr and provides a greater composite microhardness, DLC-Mg-PSZ will likely be more durable for use as a bearing surface in vivo.

  7. The effect of temperature on the tribological mechanisms and reactivity of hydrogenated, amorphous diamond-like carbon coatings under oil-lubricated conditions

    International Nuclear Information System (INIS)

    In this work we present the wear and friction behaviour of boundary-lubricated, hydrogenated, amorphous, diamond-like carbon coatings (a-C:H), in self-mated a-C:H/a-C:H contacts, at three different testing temperatures: 20, 80, 150 deg. C. We present results from Auger electron spectroscopy, X-ray photoelectron spectroscopy and Raman analyses relating to the chemical and structural changes in the diamond-like carbon coatings during sliding in the presence of mineral oil, with and without additives. We show, that chemical reactions between the a-C:H coatings and the oil additives take place, which are dependent on the temperature, on the presence of additives and the type of additives used. At high temperatures the extreme pressure additive interacts with the diamond-like carbon surface and forms a tribochemical layer with a four-times lower sulphur/phosphorous ratio than the additive formulation. In the absence of additives, however, graphitisation of the coating occurs under these conditions, which results in high-wear and low-friction behaviour. Another result from this study is that a-C:H coatings can oxidise during room-temperature experiments, suggesting that some interactions and adsorptions are also possible at lower temperatures

  8. Structural Analysis of Planar sp3 and sp2 Films: Diamond-Like Carbon and Graphene Overlayers

    KAUST Repository

    Mansour, Ahmed

    2011-07-07

    The special electronic configuration of carbon enables the existence of wide ranging allotropes taking all possible dimensionalities. The allotropes of carbon are characterized by the type of hybridized bonding forming its structure, ranging from pure sp2 as in graphene, carbon nanotubes and fullerenes, to pure sp3 as in diamond. Amorphous and diamond-like carbon consists of a mixture of both hybridizations. This variation in hybridization in carbon materials enables a wide spectrum of properties, ranging from high bulk mechanical hardness, tribological properties and chemical inertness made possible by moving towards pure sp3 bonding to the extraordinary electrical conductivity, optical properties and in-plane mechanical strength resulting from pure sp2 bonding. Two allotropes at the extremes of this spectrum, diamond like carbon (DLC) and graphene, are investigated in this thesis; the former is investigated as a protective coating in hard drive applications, while the latter is investigated in the context of chemically derived graphene as material for transparent conducting electrode applications. DLC thin films are a main component in computer hard drives, acting as a protective coating against corrosion and mechanical wear of the magnetic layer and read-write head. The thickness of DLC films greatly affects the storage density in such devices, as larger separation between the read/write head and the magnetic layer decreases the storage density. A targeted DLC thickness of 2 nm would increase the storage density towards 1 Tbits/inch2. However, difficulty achieving continuous films at such thicknesses by commonly used sputtering methods challenges the industry to investigate alternative methods. Filtered cathodic vacuum arc (FCVA) has been proposed as an efficient technique to provide continuous, smooth and ultra-thin DLC films. We investigate the influence of deposition angle, deposition time, and substrate biasing to define the optimum process window to obtain

  9. Improvement in the degradation resistance of silicon nanostructures by the deposition of diamond-like carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Klyui, N. I., E-mail: klyui@isp.kiev.ua; Semenenko, M. A.; Khatsevich, I. M.; Makarov, A. V.; Kabaldin, A. N. [National Academy of Sciences of Ukraine, Lashkarev Institute of Semiconductor Physics (Ukraine); Fomovskii, F. V. [Kremenchug National University (Ukraine); Han, Wei [Jilin University, College of Physics (China)

    2015-08-15

    It is established that the deposition of a diamond-like film onto a structure with silicon nanoclusters in a silicon dioxide matrix yields an increase in the long-wavelength photoluminescence intensity of silicon nanoclusters due to the passivation of active-recombination centers with hydrogen and a shift of the photoluminescence peak to the region of higher photosensitivity of silicon-based solar cells. It is also shown that, due to the deposited diamond-like film, the resistance of such a structure to degradation upon exposure to γ radiation is improved, which is also defined by the effect of the passivation of radiation-induced activerecombination centers by hydrogen that is released from the films during treatment.

  10. Structure and properties of Mo-containing diamond-like carbon films produced by ion source assisted cathodic arc ion-plating

    International Nuclear Information System (INIS)

    Ion source assisted cathodic arc ion-plating was used to synthesize molybdenum containing diamond-like carbon films. The element of molybdenum is uniformly distributed in our sample as analyzed by Rutherford backscattering spectroscopy. The surface morphology of the films was analyzed by scanning electron microscope and atomic force microscope. The structure and bond state of the molybdenum containing diamond-like carbon films were characterized by X-ray diffraction, high resolution transmission electron microscopy, Raman spectra, and X-ray photoelectron spectroscopy. The Mo content in the films was controlled by varying of the acetylene gas flow rates. The root-mean square roughness of the as-deposited sample was found in the range of 1.5 nm. The hardness of 35 GPa has been achieved at the optimum conditions of synthesis. This can be attributed to formation multilayer structure during deposition process and the formation of hard molybdenum carbide phase with C=Mo bonding. The results show that ion source assisted cathodic arc ion-plating is an effective technique to fabricate metal-containing carbon films with controlled metal contents.

  11. Preparation of Ag-containing diamond-like carbon films on the interior surface of tubes by a combined method of plasma source ion implantation and DC sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Hatada, R., E-mail: hatada@ca.tu-darmstadt.de [Technische Universität Darmstadt, Department of Materials Science, 64287 Darmstadt (Germany); Flege, S.; Bobrich, A.; Ensinger, W.; Dietz, C. [Technische Universität Darmstadt, Department of Materials Science, 64287 Darmstadt (Germany); Baba, K. [Industrial Technology Center of Nagasaki, Applied Technology Division, Omura, Nagasaki 856-0026 (Japan); Sawase, T.; Watamoto, T. [Nagasaki University, Department of Applied Prosthodontics, Nagasaki 852-8523 (Japan); Matsutani, T. [Technische Universität Darmstadt, Department of Materials Science, 64287 Darmstadt (Germany); Kinki University, Department of Electric and Electronic Engineering, Higashi-osaka 577-2332 (Japan)

    2014-08-15

    Highlights: • Deposition of Ag-containing diamond-like carbon films inside of tubes. • Combination of plasma source ion implantation and DC sputtering. • Antibacterial effect against S. aureus bacteria. - Abstract: Adhesive diamond-like carbon (DLC) films can be prepared by plasma source ion implantation (PSII), which is also suitable for the treatment of the inner surface of a tube. Incorporation of a metal into the DLC film provides a possibility to change the characteristics of the DLC film. One source for the metal is DC sputtering. In this study PSII and DC sputtering were combined to prepare DLC films containing low concentrations of Ag on the interior surfaces of stainless steel tubes. A DLC film was deposited using a C{sub 2}H{sub 4} plasma with the help of an auxiliary electrode inside of the tube. This electrode was then used as a target for the DC sputtering. A mixture of the gases Ar and C{sub 2}H{sub 4} was used to sputter the silver. By changing the gas flow ratios and process time, the resulting Ag content of the films could be varied. Sample characterizations were performed by X-ray photoelectron spectroscopy, secondary ion mass spectrometry, atomic force microscopy and Raman spectroscopy. Additionally, a ball-on-disk test was performed to investigate the tribological properties of the films. The antibacterial activity was determined using Staphylococcus aureus bacteria.

  12. Friction reduction in powertrain and engine components by coating with diamond-like, amorphous carbon; Reibungsminderung an Antriebs- und Motorkomponenten durch Beschichtungen mit diamantaehnlichem amorphen Kohlenstoff

    Energy Technology Data Exchange (ETDEWEB)

    Schork, Willi Sebastian

    2010-07-01

    The author investigated inhowfar coatings with diamond-like amorphous carbon (ta-C) in combination with suitable lubricants may help to reduce friction in selected powertrain and engine components. The influence of the microstructure on the stresses on layers in tribological contact was investigated using simulations. By varying the parameters of the background gas in the coating plant, hydrogen-free amorphous carbon layers of different elasticities and compositions were deposited reproducibly using a pulsed arc technology. For selective analyses of damage mechanisms in high-wear conditions, a novel tribometer for increasing loads was designed and constructed, with oscillating sliding contact and dynamic load. Failure models were established for various stress-related damge mechanisms of layered systems measured by the new tribometer. Practical tests with engines with ta-C coated piston rings proved the applicability of hydrogen-free amorphous carbon in engine applications.

  13. In vitro evaluation of diamond-like carbon coatings with a Si/SiC {sub x} interlayer on surgical NiTi alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Dalian 116024 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)]. E-mail: paul.chu@cityu.edu.hk; Yang, D.Z. [State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Dalian 116024 (China)

    2007-04-15

    Diamond-like carbon (DLC) coatings were produced with a Si/SiC {sub x} interlayer by a hybrid plasma immersion ion implantation and deposition process to improve the adhesion between the carbon layer and surgical NiTi alloy substrate. The structure, mechanical properties, corrosion resistance and biocompatibility of the coatings were evaluated in vitro by Raman spectroscopy, pin-on-disk tests, potentiodynamic polarization tests and simulated fluid immersion tests. The DLC coatings with a Si/SiC {sub x} interlayer of a suitable thickness have better adhesion, lower friction coefficients and enhanced corrosion resistance. In the simulated body fluid tests, the coatings exhibit effective corrosion protection and good biocompatibility as indicated by PC12 cell cultures. DLC films fabricated on a Si/SiC {sub x} interlayer have high potential as protective coatings for biomedical NiTi materials.

  14. Nano-hillock formation in diamond-like carbon induced by swift heavy projectiles in the electronic stopping regime: Experiments and atomistic simulations

    Science.gov (United States)

    Schwen, D.; Bringa, E.; Krauser, J.; Weidinger, A.; Trautmann, C.; Hofsäss, H.

    2012-09-01

    The formation of surface hillocks in diamond-like carbon is studied experimentally and by means of large-scale molecular dynamics simulations with 5 × 106 atoms combined with a thermal spike model. The irradiation experiments with swift heavy ions cover a large electronic stopping range between ˜12 and 72 keV/nm. Both experiments and simulations show that beyond a stopping power threshold, the hillock height increases linearly with the electronic stopping, and agree extremely well assuming an efficiency of approximately 20% in the transfer of electronic energy to the lattice. The simulations also show a transition of sp3 to sp2 bonding along the tracks with the hillocks containing almost no sp3 contribution.

  15. Hydrogen-free diamond-like carbon films prepared by microwave electron cyclotron resonance plasma-enhanced direct current magnetron sputtering

    International Nuclear Information System (INIS)

    Hydrogen-free diamond-like carbon (DLC) films were prepared by means of microwave electron cyclotron resonance plasma enhanced direct current magnetron sputtering. To study the influence of enhanced plasma on film fabrication and properties, the structures as well as mechanical and electrical properties of these films were studied as a function of applied microwave power. Results showed that higher microwave power could induce higher plasma density and electron temperature. The hardness increased from 3.5 GPa to 13 GPa with a variation of microwave power from 0 W to 1000 W. The resistivity showed a drastic increase from 4.5 x 104 Ωcm at 0 W to 1.3 x 1010 Ωcm at 1000 W. The variation of the intensity ratio I(D)/I(G) and the position of the G-peak of the DLC films with respect to changes in microwave power were also investigated by Raman spectroscopy.

  16. Nano-hillock formation in diamond-like carbon induced by swift heavy projectiles in the electronic stopping regime: Experiments and atomistic simulations

    International Nuclear Information System (INIS)

    The formation of surface hillocks in diamond-like carbon is studied experimentally and by means of large-scale molecular dynamics simulations with 5 × 106 atoms combined with a thermal spike model. The irradiation experiments with swift heavy ions cover a large electronic stopping range between ∼12 and 72 keV/nm. Both experiments and simulations show that beyond a stopping power threshold, the hillock height increases linearly with the electronic stopping, and agree extremely well assuming an efficiency of approximately 20% in the transfer of electronic energy to the lattice. The simulations also show a transition of sp3 to sp2 bonding along the tracks with the hillocks containing almost no sp3 contribution.

  17. Structure and Performance of TiC-containing Diamond-like Carbon Nanocomposite Coatings Deposited by Rectangular Cathodic Arc Ion-plating

    Institute of Scientific and Technical Information of China (English)

    XIE Guosheng; YIN Zhimin; DING Hui; LI Xiaohong; YANG Bing

    2009-01-01

    TiC-containing diamond-like carbon(TiC-DLC)nanocomposite coatings were deposited by a rectangular cathodic arc ion-plating system using C_2H_2 as reacting gas.Raman spectroscopy and transmission electron microscopy analysis show that with increasing flow rate of C_2H_2,the structure of nanocomposite coatings changes from TiC nanograin-containing to graphite nanograin-containing DLC.The hardness measurements show that the hardness decreases from 28 GPa to 18 GPa with increasing C_2H_2 flow rate.The scratch test show that a high critical load(>40 N)was obtained and exhibited a good adhesion between the coating and the substrate.Wear experiment shows that the friction coefficient of TiC-DLC nanocomposite coatings decreases with increasing C_2H_2.A low friction coefficient of 0.07 was obtained at 480 sccm C_2H_2.

  18. Thickness Effects of TiC Interlayer on Tribological Properties of Diamond-Like Carbon Prepared by Unbalanced Magnetron Sputtering Method.

    Science.gov (United States)

    Park, Chulmin; Lee, Jaehyeong; Park, Yong Seob

    2015-11-01

    We investigated the tribological properties of diamond-like carbon (DLC) films prepared with TiC interlayer of various thicknesses as the adhesive layer. DLC and TiC thin films were prepared using unbalanced magnetron (UBM) sputtering method using graphite and titanium as targets. TiC films as the interlayer were deposited under DLC films and various physical, tribological, and structural properties of the films fabricated with various TiC interlayer thicknesses were investigated. With various TiC interlayer thicknesses under DLC films, the tribological properties of films were improved with increasing thickness and the DLC/TiC layer fabricated by unbalanced magnetron sputtering method are exhibited maximum high hardness over 27 GPa and high elastic modulus over 242 GPa, and a smooth surface below 0.09 nm.

  19. Diamond-like-carbon nanoparticle production and agglomeration following UV multi-photon excitation of static naphthalene/helium gas mixtures

    Science.gov (United States)

    Walsh, A. J.; Tielens, A. G. G. M.; Ruth, A. A.

    2016-07-01

    We report the formation of nanoparticles with significant diamond character after UV multi-photon laser excitation of gaseous naphthalene, buffered in static helium gas, at room temperature. The nanoparticles are identified in situ by their absorption and scattering spectra between 400 and 850 nm, which are modeled using Mie theory. Comparisons of the particles' spectroscopic and optical properties with those of carbonaceous materials indicate a sp3/sp2 hybridization ratio of 8:1 of the particles formed. The particle extinction in the closed static (unstirred) gas-phase system exhibits a complex and quasi-oscillatory time dependence for the duration of up to several hours with periods ranging from seconds to many minutes. The extinction dynamics of the system is based on a combination of transport features and particle interaction, predominantly agglomeration. The relatively long period of agglomeration allows for a unique analysis of the agglomeration process of diamond-like carbon nanoparticles in situ.

  20. Microstructure and surface properties of chromium-doped diamond-like carbon thin films fabricated by high power pulsed magnetron sputtering

    International Nuclear Information System (INIS)

    High power pulsed magnetron sputtering (HPPMS) has attracted much interest due to the large plasma density and high ionization rate of sputtered materials. It is expected to produce a highly ionized C flux from a graphite target but unfortunately, the ionization rate of carbon is still very small and the discharge on a solid carbon target is unstable as well. In this work, a stable discharged chromium target is used in the preparation of chromium-doped diamond-like carbon (Cr-DLC) films in HPPMS in reactive C2H2 gas, but the unstable graphite. The chromium concentration in the Cr-DLC films is limited by surface poisoning due to reactive gas. Less than 2% of Cr is incorporated into the DLC films at C2H2 flow rate of 5 sccm or higher. However, as a result of the high ionization rate of the reactive gas in HPPMS, intense ion bombardment of the substrate is realized. The films show a smooth surface and a dense structure with a large sp3 concentration. As the C2H2 flow increase, the sp3 fraction increase and the sp3 to sp2 ratio increase to 0.75 at a C2H2 flow rate of 10 sccm. Compared to the substrate, the Cr-DLC films have lower friction and exhibit excellent corrosion resistance.

  1. Optical properties of diamond like carbon films containing copper, grown by high power pulsed magnetron sputtering and direct current magnetron sputtering: Structure and composition effects

    International Nuclear Information System (INIS)

    In the present study chemical composition, structure and optical properties of hydrogenated diamond like carbon films containing copper (DLC:Cu films) deposited by reactive magnetron sputtering were studied. Different modes of deposition — direct current (DC) sputtering and high power pulsed magnetron sputtering (HIPIMS) as well as two configurations of the magnetron magnetic field (balanced and unbalanced) were applied. X-ray diffractometry, Raman scattering spectroscopy, energy-dispersive X-ray spectroscopy and atomic force microscopy were used to study the structure and composition of the films. It was shown that by using HIPIMS mode contamination of the cathode during the deposition of DLC:Cu films can be suppressed. In all cases oxygen atomic concentration in the films was in 5–10 at.% range and it increased with the copper atomic concentration. The highest oxygen content was observed in the films deposited employing low ion/neutral ratio balanced DC magnetron sputtering process. According to the analysis of the parameters of Raman scattering spectra, sp3/sp2 bond ratio decreased with the increase of Cu atomic concentration in the DLC films. Clear dependence of the extinction, absorbance and reflectance spectra on copper atomic concentration in the films was observed independently of the method of deposition. Surface plasmon resonance effect was observed only when Cu atomic concentration in DLC:Cu film was at least 15 at.%. The maximum of the surface plasmon resonance peak of the absorbance spectra of DLC:Cu films was in 600–700 nm range and redshifted with the increase of Cu amount. The ratio between the intensities of the plasmonic peak and hydrogenated amorphous carbon related peak at ~ 220 nm both in the extinction and absorbance spectra as well as peak to background ratio of DLC:Cu films increased linearly with Cu amount in the investigated 0–40 at.% range. Reflectance of the plasmonic DLC:Cu films was in 30–50% range that could be important in

  2. Crack formation mechanisms during micro and macro indentation of diamond-like carbon coatings on elastic-plastic substrates

    DEFF Research Database (Denmark)

    Thomsen, N.B.; Fischer-Cripps, A.C.; Swain, M.V.

    1998-01-01

    In the present study crack formation is investigated on both micro and macro scale using spherical indenter tips. in particular, systems consisting of elastic coatings that are well adhered to elastic-plastic substrates are studied. Depth sensing indentation is used on the micro scale and Rockwell...... indentation on the macro scale. The predominant driving force for coating failure and crack formation during indentation is plastic deformation of the underlying substrate. The aim is to relate the mechanisms creating both delamination and cohesive cracking on both scales with fracture mechanical models...

  3. Reciprocating sliding behaviour of self-mated amorphous diamond-like carbon coatings on Si3N4 ceramics under tribological stress

    International Nuclear Information System (INIS)

    Amorphous diamond-like carbon films grown by magnetron sputtering have been deposited on silicon nitride based substrates for tribological purposes. A conductive Si3N4/30% vol.TiN composite was produced for bias substrate application. Friction and wear properties of carbon coated self-mated pairs were assessed using a reciprocal motion ball-on-flat setup in unlubricated conditions with applied normal loads of 3 N and 5 N. The worn surfaces were studied by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) in order to identify the prevalent wear mechanism. Unbiased and biased substrates behaved differently, the former undergoing premature delamination while the latter endured the tribological test conditions (3 N, ∼ 43 m). Very low friction coefficient values of ∼ 0.015 were sustained assuring remarkable wear behaviour. Surface grooving and wear debris accumulation in the sliding track lead to a roughness increase from the nominal rms value of ∼ 12 nm to ∼ 97 nm, although no weight loss and surface profile modification was quantifiable

  4. Ion induced transformation of polymer films into diamond-like carbon incorporating silver nano particles; Ioneninduzierte Umwandlung von Polymerschichten zu diamantaehnlichem Kohlenstoff mit darin enthaltenen Silber-Nanopartikeln

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Florian P.

    2010-03-26

    Silver containing diamond-like carbon (DLC) is an interesting material for medical engineering from several points of view. On the one hand DLC provides high mechanical robustness. It can be used as biocompatible and wear resistant coating for joint replacing implants. On the other hand silver has antimicrobial properties, which could reduce post-operative inflammations. However conventional production of Ag-DLC by co-deposition of silver and carbon in a plasma process is problematic since it does not allow for a separate control of nano particle morphology and matrix properties. In this work an alternative production method has been developed to circumvent this problem. In metall-DLC-production by ion implantation into a nano composite, silver nano particles are initially formed in solution and then incorporated within a polymer matrix. Finally the polymer is transformed into DLC by ion implantation. The aspects and single steps of this method were investigated with regard to the resulting material's properties. The goal was to design an economically relevant deposition method. Based on experimental results a model of the transformation process has been established, which has also been implemented in a computer simulation. Finally the antibacterial properties of the material have been checked in a biomedical test. Here a bacterial killing rate of 90% could be achieved. (orig.)

  5. Fabrication of High Transparency Diamond-Like Carbon Film Coating on D263T Glass at Room Temperature as an Antireflection Layer

    Directory of Open Access Journals (Sweden)

    Chii-Ruey Lin

    2013-01-01

    Full Text Available This study intends to deposit high transmittance diamond-like carbon (DLC thin films on D263T glass substrate at room temperature via a diamond powder target using the radio frequency (RF magnetron sputtering technique. Moreover, various process parameters were used to tune the properties of the thin films by using the Taguchi method. Experimental results show that the content of sp3 bonded carbon decreases in accordance with the effect of the substrate temperature. In addition, the hardness of all as-deposited single-layer DLC films ranges from 13.2 to 22.5 GPa, and the RMS surface roughness was improved significantly with the decrease in sputtering pressure. The water repellent of the deposited DLC films improved significantly with the increase of the sp3 content, and its contact angle was larger than that of the noncoated one by 1.45 times. Furthermore, the refraction index (n of all as-deposited DLC films ranges from 1.95 to 2.1 at λ = 600 nm. These results demonstrate that the thickness increased as the reflectance increased. DLC film under an RF power of 150 W possesses high transmissive ability (>81% and low average reflectance ability (<9.5% in the visible wavelengths (at λ = 400–700 nm.

  6. Nanostructured diamond-like carbon on digital versatile disc as a matrix-free target for laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Najam-ul-Haq, Muhammad; Rainer, Matthias; Huck, Christian W; Hausberger, Peter; Kraushaar, Harald; Bonn, Günther K

    2008-10-01

    A nanostructured diamond-like carbon (DLC) coated digital versatile disk (DVD) target is presented as a matrix-free sample support for application in laser desorption/ionization mass spectrometry (LDI-MS). A large number of vacancies, defects, relative sp(2) carbon content, and nanogrooves of DLC films support the LDI phenomenon. The observed absorptivity of DLC is in the range of 305-330 nm (nitrogen laser, 337 nm). The universal applicability is demonstrated through different analytes like amino acids, carbohydrates, lipids, peptides, and other metabolites. Carbohydrates and amino acids are analyzed as sodium and potassium adducts. Peptides are detectable in their protonated forms, which avoid the extra need of additives for ionization. A bovine serum albumin (BSA) digest is analyzed to demonstrate the performance for peptide mixtures, coupled with the material-enhanced laser desorption/ionization (MELDI) approach. The detection limit of the described matrix-free target is investigated to be 10 fmol/microL for [Glu(1)]-fibrinopeptide B (m/z 1570.6) and 1 fmol/microL for L-sorbose (Na(+) adduct). The device does not require any chemical functionalization in contrast to other matrix-free systems. The inertness of DLC provides longer lifetimes without any deterioration in the detection sensitivity. Broad applicability allows high performance analysis in metabolomics and peptidomics. Furthermore the DLC coated DVD (1.4 GB) sample support is used as a storage device for measured and processed data together with sampling on a single device. PMID:18729472

  7. Preparation of diamond-like carbon films using reactive Ar/CH4 high power impulse magnetron sputtering system with negative pulse voltage source for substrate

    Science.gov (United States)

    Kimura, Takashi; Kamata, Hikaru

    2016-04-01

    Diamond-like carbon films were prepared using a reactive Ar/CH4 high-power impulse magnetron sputtering system with a negative pulse voltage source for the substrate, changing the CH4 fraction up to 15% in the total pressure range from 0.3 to 2 Pa. The magnitude of the negative pulse voltage for the substrate was also varied up to about 500 V. The hardness of films monotonically increased with increasing magnitude of the negative pulse voltage. The films with hardnesses between 16.5 and 23 GPa were prepared at total pressures less than 0.5 Pa and CH4 fractions less than 10% by applying an appropriate negative pulse voltage of 300-400 V. In X-ray photoelectron spectroscopy, the area ratio C-C sp3/(C-C sp2 + C-C sp3) in the C 1s core level was higher than 30% at pressures less than 0.5 Pa and CH4 fractions less than 15%. On the other hand, the films with hardnesses between 5 and 10 GPa were prepared with a relatively high growth rate at the partial pressures of CH4 higher than 0.1 Pa. However, the observation of the photoluminescence background in Raman spectroscopy indicated a relatively high hydrogen content.

  8. Influence of Microwave Power on the Properties of Hydrogenated Diamond-Like Carbon Films Prepared by ECR Plasma Enhanced DC Magnetron Sputtering

    International Nuclear Information System (INIS)

    Electron cyclotron resonance (ECR) plasma was applied to enhance the direct current magnetron sputtering to prepare hydrogenated diamond-like carbon (H-DLC) films. For different microwave powers, both argon and hydrogen gas are introduced separately as the ECR working gas to investigate the influence of microwave power on the microstructure and electrical property of the H-DLC films deposited on P-type silicon substrates. A series of characterization methods including the Raman spectrum and atomic force microscopy are used. Results show that, within a certain range, the increase in microwave power affects the properties of the thin films, namely the sp3 ratio, the hardness, the nanoparticle size and the resistivity all increase while the roughness decreases with the increase in microwave power. The maximum of resistivity amounts to 1.1 x 109 Ω · cm. At the same time it is found that the influence of microwave power on the properties of H-DLC films is more pronounced when argon gas is applied as the ECR working gas, compared to hydrogen gas.

  9. Intermittent chemical vapor deposition of thick electrically conductive diamond-like amorphous carbon films using i-C4H10/N2 supermagnetron plasma

    International Nuclear Information System (INIS)

    Electrically conductive diamond-like amorphous carbon (DAC) films with nitrogen (DAC:N) were deposited on Si and SiO2 wafers using the i-C4H10/N2 supermagnetron plasma chemical vapor deposition (CVD) method. Resistivity and hardness decreased with increase of upper electrode rf power (UPRF) under constant lower electrode rf power (LORF). Film thickness increased linearly to over 0.3 μm with deposition time via intermittent deposition. The film exhibited good adhesion to the substrate. Low-resistance thick films were deposited using alternating multilayer CVD at UPRF/LORFs of 1 kW/1 kW and 300 W/300 W. In the deposited alternating multiple layers, resistivity significantly decreased with the increase of H layer (1 kW/1 kW) thickness, and film thickness significantly increased with the increase of L layer (300 W/300 W) thickness. By the deposition of H/L multiple layers, a film of 2.1 μm thickness and 0.14 Ω cm resistivity was obtained

  10. Effect of tetramethylsilane flow on the deposition and tribological behaviors of silicon doped diamond-like carbon rubbed against poly(oxymethylene)

    Science.gov (United States)

    Deng, Xingrui; Lim, Yankuang; Kousaka, Hiroyuki; Tokoroyama, Takayuki; Umehara, Noritsugu

    2014-11-01

    In this study, silicon doped diamond-like carbon (Si-DLC) was deposited on stainless steel (JIS SUS304) by using surface wave-excited plasma (SWP). The effects of tetramethylsilane (TMS) flow on the composition, topography, mechanical properties and tribological behavior were investigated. Pin-on-disc tribo-meter was used to investigate the tribological behavior of the Si-DLC coating rubbed against poly(oxymethylene) (POM). The results show that the deposition rate, roughness of Si-DLC increased and the hardness of Si-DLC decreased with the increase of TMS flow rate from 2 to 4 sccm; the roughness increase therein led to the increase of ploughing term of friction. The increase of adhesion term was also seen with the increase of TMS flow rate, being attributed to the decrease of hydrogen concentration in the coating. It was considered that more POM transferred onto the Si-DLC deposited at higher TMS flow rate due to larger heat generation by friction.

  11. Effects of frequency of pulsed substrate bias on structure and properties of silicon-doped diamond-like carbon films by plasma deposition

    International Nuclear Information System (INIS)

    We have investigated the effects of the frequency of pulsed substrate bias on the structure and properties of Si-doped diamond-like carbon (Si-DLC) films deposited by radio-frequency plasma-enhanced chemical vapor deposition using CH4, Ar, and monomethylsilane (CH3SiH3) as the Si source. The Si/(Si + C) ratios in the Si-DLC films deposited using pulsed bias were higher than that of the dc-biased Si-DLC film, and the Si fraction increased with decreasing frequency. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses revealed that Si–C, Si–Hn, and C–Hn bonds in the Si-DLC films increased with decreasing frequency. The internal stress decreased as the frequency decreased, which is probably due to the increase in Si–C, Si–Hn, and C–Hn bonds in the films. It was found that the wear rate of the pulse-biased Si-DLC film deposited at the highest frequency in this study is comparable to that of the dc-biased, undoped DLC film. Furthermore, the friction coefficient of the former is about one third of that of the latter. - Highlights: • The tribological properties of Si-doped films were improved at higher frequencies. • The internal stress of Si-doped films was lowered at lower frequencies. • The adhesion of pulse-biased films was improved at lower frequencies

  12. Influence of high temperature annealing on the structure, hardness and tribological properties of diamond-like carbon and TiAlSiCN nanocomposite coatings

    Science.gov (United States)

    Xie, Z. W.; Wang, L. P.; Wang, X. F.; Huang, L.; Lu, Y.; Yan, J. C.

    2011-11-01

    Diamond-like carbon (DLC) and TiAlSiCN nanocomposite coatings were synthesized and annealed at different temperatures in a vacuum environment. The microstructure, hardness and tribological properties of as-deposited and annealed DLC-TiAlSiCN nanocomposite coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, nano-indentation and friction tests. The TEM results reveal that the as-deposited DLC-TiAlSiCN coating has a unique nanocomposite structure consisting of TiCN nanocrystals embedded in an amorphous matrix consisting of a-Si3N4, a-SiC, a-CN and DLC, and the structure changed little after annealing at 800 °C. However, XPS and Raman results show that an obvious graphitization of the DLC phase occurred during the annealing process and it worsened with annealing temperature. Because of the graphitization, the hardness of the DLC-TiAlSiCN coating after annealing at 800 °C decreased from 45 to 36 GPa. In addition, the DLC-TiAlSiCN coating after annealing at 800 °C has a similar friction coefficient to the as-deposited coating.

  13. Influence of high temperature annealing on the structure, hardness and tribological properties of diamond-like carbon and TiAlSiCN nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Z.W. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, L.P., E-mail: aplpwang@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, X.F.; Huang, L.; Lu, Y.; Yan, J.C. [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)

    2011-11-15

    Diamond-like carbon (DLC) and TiAlSiCN nanocomposite coatings were synthesized and annealed at different temperatures in a vacuum environment. The microstructure, hardness and tribological properties of as-deposited and annealed DLC-TiAlSiCN nanocomposite coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, nano-indentation and friction tests. The TEM results reveal that the as-deposited DLC-TiAlSiCN coating has a unique nanocomposite structure consisting of TiCN nanocrystals embedded in an amorphous matrix consisting of a-Si{sub 3}N{sub 4}, a-SiC, a-CN and DLC, and the structure changed little after annealing at 800 Degree-Sign C. However, XPS and Raman results show that an obvious graphitization of the DLC phase occurred during the annealing process and it worsened with annealing temperature. Because of the graphitization, the hardness of the DLC-TiAlSiCN coating after annealing at 800 Degree-Sign C decreased from 45 to 36 GPa. In addition, the DLC-TiAlSiCN coating after annealing at 800 Degree-Sign C has a similar friction coefficient to the as-deposited coating.

  14. Influence of high temperature annealing on the structure, hardness and tribological properties of diamond-like carbon and TiAlSiCN nanocomposite coatings

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) and TiAlSiCN nanocomposite coatings were synthesized and annealed at different temperatures in a vacuum environment. The microstructure, hardness and tribological properties of as-deposited and annealed DLC-TiAlSiCN nanocomposite coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, nano-indentation and friction tests. The TEM results reveal that the as-deposited DLC-TiAlSiCN coating has a unique nanocomposite structure consisting of TiCN nanocrystals embedded in an amorphous matrix consisting of a-Si3N4, a-SiC, a-CN and DLC, and the structure changed little after annealing at 800 °C. However, XPS and Raman results show that an obvious graphitization of the DLC phase occurred during the annealing process and it worsened with annealing temperature. Because of the graphitization, the hardness of the DLC-TiAlSiCN coating after annealing at 800 °C decreased from 45 to 36 GPa. In addition, the DLC-TiAlSiCN coating after annealing at 800 °C has a similar friction coefficient to the as-deposited coating.

  15. Investigation of the microstructure, mechanical properties and tribological behaviors of Ti-containing diamond-like carbon films fabricated by a hybrid ion beam method

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Wei [Ningbo Key Laboratory of Marine Protection Materials, Division of Surface Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Future Convergence Technology Division, Korea Institute of Science and Technology, Seoul, 130-650 (Korea, Republic of); Ke, Peiling [Ningbo Key Laboratory of Marine Protection Materials, Division of Surface Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Moon, Myoung-Woon; Lee, Kwang-Ryeol [Future Convergence Technology Division, Korea Institute of Science and Technology, Seoul, 130-650 (Korea, Republic of); Wang, Aiying, E-mail: aywang@nimte.ac.cn [Ningbo Key Laboratory of Marine Protection Materials, Division of Surface Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2012-07-31

    Diamond-like carbon (DLC) films with various titanium contents were investigated using a hybrid ion beam system comprising an anode-layer linear ion beam source and a DC magnetron sputtering unit. The film composition and microstructure were characterized carefully by X-ray photoelectron spectroscopy, transmission electron microscopy and Raman spectroscopy, revealing that the doped Ti atoms had high solubility in the DLC films. The maximum solubility was found to lie between about 7 and 13 at.%. When the Ti content was lower than this solubility, the doped Ti atoms dissolved in the DLC matrix and the films exhibited the typical features of the amorphous DLC structure and displayed low compressive stresses, friction coefficients and wear rates. However, as the doped content exceeded the solubility, Ti atoms bonded with C atoms, resulting in the formation of carbide nano-particles embedded in the DLC matrix. Although the emergence of the carbide nano-particles promoted graphitizing due to a catalysis effect, the film hardness was enhanced to a great extent. On the other hand, the hard carbides particles caused abrasive wear behavior, inducing a high friction coefficient and wear rate. - Highlights: Black-Right-Pointing-Pointer Ti doped DLC films (Ti {approx} 24 at.% )were deposited by a hybrid ion beam system. Black-Right-Pointing-Pointer Solubility of the Ti atoms in the DLC films was found around 7 {approx} 13 at .%. Black-Right-Pointing-Pointer Microstructure evolution from DLC to nanocomposite played key role in film behaviors.

  16. Near edge X-ray absorption fine structure study for optimization of hard diamond-like carbon film formation with Ar cluster ion beam

    CERN Document Server

    Kitagawa, T; Kanda, K; Shimizugawa, Y; Toyoda, N; Matsui, S; Yamada, I; Tsubakino, H; Matsuo, J

    2003-01-01

    Diamond-like carbon (DLC) film deposited using C sub 6 sub 0 vapor with simultaneous irradiation of an Ar cluster ion beam was characterized by a near edge X-ray absorption fine structure (NEXAFS), in order to optimize the hard DLC film deposition conditions. Contents of sp sup 2 orbitals in the films, which were estimated from NEXAFS spectra, are 30% lower than that of a conventional DLC film deposited by a RF plasma method. Those contents were obtained under the flux ratio of the C sub 6 sub 0 molecules to the Ar cluster ions to range from 1 to 20, at 5keV of Ar cluster ion acceleration energy. Average hardness of the films was 50 GPa under these flux ratios. This hardness was three times higher than that of a conventional DLC film. Furthermore, the lowest sp sup 2 content and above-mentioned high hardness were obtained at room temperature of the substrate when the depositions were performed in the range of the substrate temperature from room temperature to 250degC. (author)

  17. Synchrotron radiation photoelectron spectroscopy and near-edge X-ray absorption fine structure study on oxidative etching of diamond-like carbon films by hyperthermal atomic oxygen

    International Nuclear Information System (INIS)

    Surface structural changes of a hydrogenated diamond-like carbon (DLC) film exposed to a hyperthermal atomic oxygen beam were investigated by Rutherford backscattering spectroscopy (RBS), synchrotron radiation photoelectron spectroscopy (SR-PES), and near-edge X-ray absorption fine structure (NEXAFS). It was confirmed that the DLC surface was oxidized and etched by high-energy collisions of atomic oxygen. RBS and real-time mass-loss data showed a linear relationship between etching and atomic oxygen fluence. SR-PES data suggested that the oxide layer was restricted to the topmost surface of the DLC film. NEXAFS data were interpreted to mean that the sp2 structure at the DLC surface was selectively etched by collisions with hyperthermal atomic oxygen, and an sp3-rich region remained at the topmost DLC surface. The formation of an sp3-rich layer at the DLC surface led to surface roughening and a reduced erosion yield relative to the pristine DLC surface.

  18. A novel radial anode layer ion source for inner wall pipe coating and materials modification--hydrogenated diamond-like carbon coatings from butane gas.

    Science.gov (United States)

    Murmu, Peter P; Markwitz, Andreas; Suschke, Konrad; Futter, John

    2014-08-01

    We report a new ion source development for inner wall pipe coating and materials modification. The ion source deposits coatings simultaneously in a 360° radial geometry and can be used to coat inner walls of pipelines by simply moving the ion source in the pipe. Rotating parts are not required, making the source ideal for rough environments and minimizing maintenance and replacements of parts. First results are reported for diamond-like carbon (DLC) coatings on Si and stainless steel substrates deposited using a novel 360° ion source design. The ion source operates with permanent magnets and uses a single power supply for the anode voltage and ion acceleration up to 10 kV. Butane (C4H10) gas is used to coat the inner wall of pipes with smooth and homogeneous DLC coatings with thicknesses up to 5 μm in a short time using a deposition rate of 70 ± 10 nm min(-1). Rutherford backscattering spectrometry results showed that DLC coatings contain hydrogen up to 30 ± 3% indicating deposition of hydrogenated DLC (a-C:H) coatings. Coatings with good adhesion are achieved when using a multiple energy implantation regime. Raman spectroscopy results suggest slightly larger disordered DLC layers when using low ion energy, indicating higher sp(3) bonds in DLC coatings. The results show that commercially interesting coatings can be achieved in short time. PMID:25173323

  19. Diamond-like carbon (DLC) thin film bioelectrodes: Effect of thermal post-treatments and the use of Ti adhesion layer

    Energy Technology Data Exchange (ETDEWEB)

    Laurila, Tomi, E-mail: tomi.laurila@aalto.fi [Department of Electronics, School of Electrical Engineering, Aalto University, Espoo (Finland); Rautiainen, Antti [Department of Electronics, School of Electrical Engineering, Aalto University, Espoo (Finland); Sintonen, Sakari [Department of Micro- and Nanotechnology, School of Electrical Engineering, Aalto University, Espoo (Finland); Jiang, Hua [Department of Applied Physics, School of Science, Aalto University, Espoo (Finland); Kaivosoja, Emilia [Department of Electronics, School of Electrical Engineering, Aalto University, Espoo (Finland); Helsinki University Central Hospital, Institute of Clinical Medicine (Finland); Koskinen, Jari [Department of Materials Science, School of Chemical Technology, Aalto University, Espoo (Finland)

    2014-01-01

    The effect of thermal post-treatments and the use of Ti adhesion layer on the performance of thin film diamond like carbon bioelectrodes (DLC) have been investigated in this work. The following results were obtained: (i) The microstructure of the DLC layer after the deposition was amorphous and thermal annealing had no marked effect on the structure, (ii) formation of oxygen containing SiO{sub x} and Ti[O,C] layers were detected at the Si/Ti and Ti/DLC interfaces with the help of transmission electron microscope (TEM), (iii) thermal post-treatments increased the polar fraction of the surface energy, (iv) cyclic voltammetry (CV) measurements showed that the DLC films had wide water windows and were stable in contact with dilute sulphuric acid and phosphate buffered saline (PBS) solutions, (v) use of Ti interlayer between Pt(Ir) microwire and DLC layer was crucial for the electrodes to survive the electrochemical measurements without the loss of adhesion of the DLC layer, (vi) DLC electrodes with small exposed Pt areas were an order of magnitude more sensitive towards dopamine than Pt electrodes and (vii) thermal post-treatments did not markedly change the electrochemical behavior of the electrodes despite the significant increase in the polar nature of the surfaces. It can be concluded that thin DLC bioelectrodes are stable under physiological conditions and can detect dopamine in micro molar range, but their sensitivity must be further improved. - Highlights: • Crucial effect of Ti adhesion layer on the performance of DLC bioelectrodes is shown. • Amorphous SiOx and Ti[C,O]x are shown to form at the Si/Ti and Ti/DLC interfaces. • Thermal annealing can be used to oxidize the surface of DLC films. • However, there is no change in the sensitivity of the electrodes towards dopamine. • DLC/Pt composite electrodes have improved sensitivity.

  20. Influence of duty ratio of pulsed bias on structure and properties of silicon-doped diamond-like carbon films by plasma deposition

    International Nuclear Information System (INIS)

    We have investigated the influence of the duty ratio of pulsed substrate bias on the structure and properties of Si-doped diamond-like carbon (Si-DLC) films deposited by radio frequency plasma-enhanced chemical vapor deposition using CH4, Ar, and monomethylsilane (CH3SiH3) as the Si source. The Si/(Si + C) ratios in the Si-DLC films deposited using pulsed bias were higher than that of the dc-biased Si-DLC film, and the Si fraction increased with decreasing pulse duty ratio. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses revealed that Si-C, Si-Hn, and C-Hn bonds in the Si-DLC films increased with decreasing duty ratio. The internal stress decreased as the duty ratio decreased, which is probably due to the increase in Si-C, Si-Hn, and C-Hn bonds in the films. The Si-DLC films deposited using pulsed bias had higher adhesion strength than the dc-biased Si-DLC film because of the further reduction of internal stress. At higher duty ratios, although the Si fractions of the pulse-biased Si-DLC films were higher than that of the dc-biased Si-DLC film, the wear rates of the former were less than that of the latter. - Highlights: • The internal stress of Si-doped films was lowered at lower duty ratios. • The adhesion of pulse-biased films was improved compared with that of dc films. • The tribological properties of Si-doped films were improved by the use of pulse bias

  1. Influence of W content on tribological performance of W-doped diamond-like carbon coatings under dry friction and polyalpha olefin lubrication conditions

    International Nuclear Information System (INIS)

    Highlights: • W-doped DLC coating with various W contents was fabricated. • Friction and wear of DLC coated sample was studied. • The lubricant additive was T307. • The influence of W content on friction under lubrication was unveiled. • The influence of W content on wear under lubrication was studied. - Abstract: The influence on tungsten content on the structure, mechanical properties and tribological performance of W-doped diamond-like carbon (DLC) coatings was studied by X-ray photoelectron spectroscopy, nano-indentation, scratch test, and ball-on-disk friction test. It was found that with increasing W content, the content of WC and free W in the coatings is increased while the content of sp3-C in the coatings is decreased. The effect of W content on the hardness and elastic modulus of the coatings is indistinctive, but there exists the highest critical load of scratch test of above 100 N when W content is 3.08 at.%. With the increase of W content, the friction coefficients of W-doped DLC coatings under dry friction conditions are increased while the friction coefficients of W-doped DLC coatings under polyalpha olefin (PAO) lubrication are decreased. With the increase of W content, the wear rates of the DLC-coated samples under dry friction conditions show a minimum value; under pure PAO lubrication, the influence of W content on the wear rates of the DLC-coated samples is indistinctive when the W content is below 10.73 at.% while the wear rates are increased with increasing W content from 10.73 at.% to 24.09 at.%; when lubricated by PAO + thiophosphoric acid amine (T307) salt, the samples coated with the undoped DLC or the W-doped DLC with high W content exhibit low wear rates

  2. Effects of electrical conductivity of substrate materials on microstructure of diamond-like carbon films prepared by bipolar-type plasma based ion implantation

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) films are prepared by a bipolar-type plasma based ion implantation, and the structural differences between DLC films deposited on different electrical conductive substrates, i.e., conductive Si wafers and insulating glass plates are examined by Raman spectroscopy and x-ray photo emission spectroscopy (XPS). In the Raman measurements, graphite (G) and disorder (D) peaks are observed for both samples. However, the additional photo luminescence is overlapped on the spectra in the case of on-glass sample. To elucidate the structural difference, the intensity ratio of D to G peak (I(D)/I(G)), G peak position and full width at half maximum (FWHM) are obtained by curve fitting using Gaussian function and linear baseline. It is found that the I(D)/I(G) is lower, G peak position is higher and FWHM of G peak is narrower for on-glass sample than for on-Si sample. According to Robertson [1], lower I(D)/I(G) seems more sp3 C-C bonding in amount for on-glass sample. In contrast, higher G peak position and narrower FWHM of G peak suggest less sp3 C-C bonding in amount for on-glass sample. The results of XPS analysis with C1s spectra reveal that sp3 ratio, i.e., the intensity ratio of sp3/(sp3+sp2) is smaller for on-glass sample than for on-Si sample. The inconsistency of the trend between I(D)/I(G) and other parameters (G peak position and FWHM of G peak) might be caused by the overlap of photo luminescence signal on Raman spectrum as to on-glass sample. From these results, it is considered that sp3 C-C bonding is reduced in amount when using insulating substrate in comparison with conductive substrate.

  3. The change of bacterial adhesion during deposition nitrogen-diamond like carbon coating on pure titanium%渗氮类金刚石薄膜应用于纯钛后的细菌黏附变化

    Institute of Scientific and Technical Information of China (English)

    尹路; 肖云

    2011-01-01

    Objective The aim of this study was to observe the change of bacterial adhesion on pure titanium coated with nitrogen-diamond like carbon (N-DLC) films and to guide the clinical application. Methods N-DLC was deposited on titanium using ion plating machine, TiN film, anodic oxide film and non-deposition were used as control, then made specimens adhering on the surface of resin denture base for 6 months. The adhesion of Saccharomyces albicans on the titanium surface was observed using scanning electron microscope, and the roughness was tested by roughness detector. Results The number of Saccharomyces albicans adhering on diamond-like carbon film was significantly less than on the other groups (P<0.05), and the growth of bacterial cell was inhibited and in a poor state. The largest number of adhesion and cell strains grew well on anodic oxide film group and non-deposition control group. The change of surface roughness of N-DLC film was less than other group (P<0.05). Conclusion Pure titanium coated with N-DLC film reduced the adhesion of Saccharomyces albicans after clinical application, thereby reduced the risk of denture stomatitis.%目的 观察纯钛试件应用等离子镀膜法镀制纳米渗氮类金刚石(N-DLC)薄膜后的细菌黏附变化,以期对临床应用有所指导.方法 采用等离子镀膜机,在纯钛试件表面沉积N -DLC薄膜、TiN薄膜、阳极氧化膜以及空白对照,然后将其黏附于树脂基托表面,实际使用6个月后,扫描电子显微镜观察白色假丝酵母菌黏附试件情况;粗糙度检测仪对比检测试件粗糙度变化.结果 白色假丝酵母菌在N-DLC膜表面附着数量比其他组试件明显少(P<0.05),且菌体生长不良,处于抑制状态;阳极氧化膜和空白对照试件表面黏附菌量最多,且菌体生长旺盛.N-DLC膜表面粗糙度在戴用前后变化最小(P<0.05).结论 纯钛表面镀制N-DLC膜在口腔实际应用过程中可以明显降低白色假丝酵母菌的黏

  4. Influence of zinc dialkyldithiophosphate tribofilm formation on the tribological performance of self-mated diamond-like carbon contacts under boundary lubrication

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) coatings offer excellent mechanical and tribological properties that make them suitable protective coatings for various industrial applications. In recent years, several engine and power train components in passenger cars, which work under boundary lubricated conditions, have been coated with DLC coatings. Since conventional lubricants and lubricant additives are formulated for metal surfaces, there are still controversial questions concerning chemical reactivity between DLC surfaces and common lubricant additives owing to the chemical inertness of DLC coatings. In this work, we present the influence of zinc dialkyldithiophosphate (ZnDTP) anti-wear additives on the tribological performance of various self-mated DLC coatings under boundary lubrication conditions. The effects of hydrogen, doping elements, and surface morphology on the reactivity of DLC coatings to form a ZnDTP-derived tribofilm were investigated by atomic force microscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy. The results confirmed that ZnDTP-derived pad-like or patchy tribofilm forms on the surfaces depending on the DLC coating. It is seen that hydrogen content and doping elements increase pad-like tribofilm formation. Doped DLC coatings are found to give better wear resistance than non-doped DLC coatings. Furthermore, the addition of ZnDTP additives to the base oil significantly improves the wear resistance of hydrogenated DLC, silicon-doped hydrogenated DLC, and chromium-doped hydrogenated DLC. Hydrogen-free tetrahedral amorphous DLC coatings provide the lowest friction coefficient both in PAO (poly-alpha-olefin) and PAO + ZnDTP oils. - Highlights: • Zinc dialkyldithiophosphate (DTP) tribofilm formation on various DLC surfaces was evidenced. • Pad-like tribofilm was found on a-C:H, a-C, Si-DLC and Cr-DLC. • Pad-like tribofilm on DLC surfaces greatly increased the wear resistance. • Hydrogenated and doped DLC coatings are

  5. Influence of zinc dialkyldithiophosphate tribofilm formation on the tribological performance of self-mated diamond-like carbon contacts under boundary lubrication

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah Tasdemir, H., E-mail: habdullah46@gmail.com [Department of Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Tokoroyama, Takayuki; Kousaka, Hiroyuki; Umehara, Noritsugu [Department of Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Mabuchi, Yutaka [Nissan Motor Co. (Japan)

    2014-07-01

    Diamond-like carbon (DLC) coatings offer excellent mechanical and tribological properties that make them suitable protective coatings for various industrial applications. In recent years, several engine and power train components in passenger cars, which work under boundary lubricated conditions, have been coated with DLC coatings. Since conventional lubricants and lubricant additives are formulated for metal surfaces, there are still controversial questions concerning chemical reactivity between DLC surfaces and common lubricant additives owing to the chemical inertness of DLC coatings. In this work, we present the influence of zinc dialkyldithiophosphate (ZnDTP) anti-wear additives on the tribological performance of various self-mated DLC coatings under boundary lubrication conditions. The effects of hydrogen, doping elements, and surface morphology on the reactivity of DLC coatings to form a ZnDTP-derived tribofilm were investigated by atomic force microscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy. The results confirmed that ZnDTP-derived pad-like or patchy tribofilm forms on the surfaces depending on the DLC coating. It is seen that hydrogen content and doping elements increase pad-like tribofilm formation. Doped DLC coatings are found to give better wear resistance than non-doped DLC coatings. Furthermore, the addition of ZnDTP additives to the base oil significantly improves the wear resistance of hydrogenated DLC, silicon-doped hydrogenated DLC, and chromium-doped hydrogenated DLC. Hydrogen-free tetrahedral amorphous DLC coatings provide the lowest friction coefficient both in PAO (poly-alpha-olefin) and PAO + ZnDTP oils. - Highlights: • Zinc dialkyldithiophosphate (DTP) tribofilm formation on various DLC surfaces was evidenced. • Pad-like tribofilm was found on a-C:H, a-C, Si-DLC and Cr-DLC. • Pad-like tribofilm on DLC surfaces greatly increased the wear resistance. • Hydrogenated and doped DLC coatings are

  6. Differences in the tribological mechanisms when using non-doped, metal-doped (Ti, WC), and non-metal-doped (Si) diamond-like carbon against steel under boundary lubrication, with and without oil additives

    OpenAIRE

    Kalin, Mitjan; Vižintin, Jože

    2015-01-01

    In this paper, we report on the tribological performance and mechanisms of the boundary-lubricated contacts of steel against diamond-like carbon (DLC) coatings, i.e., steel/DLC, using the same materials, oils, additives and conditions as we have previously reported for DLC/DLC contacts. We present and compare the behaviour of two non-doped, two metal-doped (Ti, WC) and one non-metal-doped (Si) DLC coatings in contact with steel surfaces in reciprocating sliding, lubricated with a paraffinic m...

  7. Diamond and Diamond-Like Materials as Hydrogen Isotope Barriers

    International Nuclear Information System (INIS)

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The purpose of this project was to develop diamond and diamond-like thin-films as hydrogen isotope permeation barriers. Hydrogen embrittlement limits the life of boost systems which otherwise might be increased to 25 years with a successful non-reactive barrier. Applications in tritium processing such as bottle filling processes, tritium recovery processes, and target filling processes could benefit from an effective barrier. Diamond-like films used for low permeability shells for ICF and HEDP targets were also investigated. Unacceptable high permeabilities for hydrogen were obtained for plasma-CVD diamond-like-carbon films

  8. The Role of Ambient Gas and Pressure on the Structuring of Hard Diamond-Like Carbon Films Synthesized by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Andrei C. Popescu

    2015-06-01

    Full Text Available Hard carbon thin films were synthesized on Si (100 and quartz substrates by the Pulsed Laser Deposition (PLD technique in vacuum or methane ambient to study their suitability for applications requiring high mechanical resistance. The deposited films’ surface morphology was investigated by scanning electron microscopy, crystalline status by X-ray diffraction, packing and density by X-ray reflectivity, chemical bonding by Raman and X-ray photoelectron spectroscopy, adherence by “pull-out” measurements and mechanical properties by nanoindentation tests. Films synthesized in vacuum were a-C DLC type, while films synthesized in methane were categorized as a-C:H. The majority of PLD films consisted of two layers: one low density layer towards the surface and a higher density layer in contact with the substrate. The deposition gas pressure played a crucial role on films thickness, component layers thickness ratio, structure and mechanical properties. The films were smooth, amorphous and composed of a mixture of sp3-sp2 carbon, with sp3 content ranging between 50% and 90%. The thickness and density of the two constituent layers of a film directly determined its mechanical properties.

  9. 含硅类金刚石膜硬度压痕测试的有限元模拟%Finite Element Simulation of Indentation Testing for Hardness of Si-Containing Diamond-Like Carbon Film

    Institute of Scientific and Technical Information of China (English)

    刘璨; 兰惠清

    2012-01-01

    使用Abaqus有限元软件通过加载荷与加载位移两种方法对含硅类金刚石膜进行了压痕测试模拟,得到了不同硅含量类金刚石膜的硬度曲线。结果表明:两种方法的模拟结果较吻合,其中加载位移的方法较稳定,速度较快,含硅类金刚石膜的硬度随着硅含量的增加而减小;模拟结果得到了相关试验的验证。%The simulation for indentation testing of Si-containing diamond-like carbon(Si-DLC) film was carried out by infinite element simulation software Abaqus using loading and displacement methods,and the hardness of the diamond-like carbon film with different silicon contents was obtained.The results show that the two methods fit fairly well,the displacement method was fairly stable and its speed also was fairly quick,and the hardness of Si-DLC film decreased with the increase of the silicon content.The finite element simulation was in agreement with correlative experiments.

  10. Bacterial adherence on fluorinated carbon based coatings deposited on polyethylene surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Terriza, A; Del Prado, G; Perez, A Ortiz; Martinez, M J; Puertolas, J A; Manso, D Molina; Gonzalez-Elipe, A R; Yubero, F; Barrena, E Gomez; Esteban, J, E-mail: antonia.terriza@icmse.csic.es

    2010-11-01

    Development of intrinsically antibacterial surfaces is of key importance in the context of prostheses used in orthopaedic surgery. In this work we present a thorough study of several plasma based coatings that may be used with this functionality: diamond like carbon (DLC), fluorine doped DLC (F-DLC) and a high fluorine content carbon-fluor polymer (CF{sub X}). The study correlates the surface chemistry and hydrophobicity of the coating surfaces with their antibacterial performance. The coatings were deposited by RF-plasma assisted deposition at room temperature on ultra high molecular weight polyethylene (UHMWPE) samples. Fluorine content and relative amount of C-C and C-F bond types was monitored by X-ray photoelectron spectroscopy and hydrophobicity by water contact angle measurements. Adherence of Staphylococcus aureus and Staphylococcus epidermidis to non-coated and coated UHMWPE samples was evaluated. Comparisons of the adherence performance were evaluated using a paired t test (two materials) and a Kruskall Wallis test (all the materials). S. aureus was statistically significant (p< 0.001) less adherent to DLC and F-DLC surfaces than S. epidermidis. Both bacteria showed reduction of adherence on DLC/UHMWPE. For S. aureus, reduction of bacterial adherence on F-DLC/UHMWPE was statistically significant respect to all other materials.

  11. P掺杂类金刚石薄膜的制备及生物学行为研究%Phosphorus doped diamond-like carbon films fabricated by plasma immersion ion implantation - deposition and study of biological behavior

    Institute of Scientific and Technical Information of China (English)

    王进; 杨萍; 陈俊英; 冷永祥; 万国江; 孙鸿; 赵安莎; 黄楠

    2004-01-01

    应用等离子体浸没离子注入与沉积方法合成了磷掺杂的类金刚石(diamond like carbon,DLC)薄膜.结构分析表明磷以微米级岛状结构分散于DLC薄膜表层,P的掺杂增加了DLC薄膜的无序性,俄歇能谱表明岛型区域是由P、C、O三种元素形成的化合物.掺杂表面表现出强烈的亲水性(水接触角为16.9°),体外血小板粘附实验结果显示,P掺杂DLC薄膜表面粘附的血小板少且变形小,表现出的血液相容性优于热解碳和未改性DLC.

  12. Regression Analysis of the Effect of Bias Voltage on Nano- and Macrotribological Properties of Diamond-Like Carbon Films Deposited by a Filtered Cathodic Vacuum Arc Ion-Plating Method

    Directory of Open Access Journals (Sweden)

    Shojiro Miyake

    2014-01-01

    Full Text Available Diamond-like carbon (DLC films are deposited by bend filtered cathodic vacuum arc (FCVA technique with DC and pulsed bias voltage. The effects of varying bias voltage on nanoindentation and nanowear properties were evaluated by atomic force microscopy. DLC films deposited with DC bias voltage of −50 V exhibited the greatest hardness at approximately 50 GPa, a low modulus of dissipation, low elastic modulus to nanoindentation hardness ratio, and high nanowear resistance. Nanoindentation hardness was positively correlated with the Raman peak ratio Id/Ig, whereas wear depth was negatively correlated with this ratio. These nanotribological properties highly depend on the films’ nanostructures. The tribological properties of the FCVA-DLC films were also investigated using a ball-on-disk test. The average friction coefficient of DLC films deposited with DC bias voltage was lower than that of DLC films deposited with pulse bias voltage. The friction coefficient calculated from the ball-on-disk test was correlated with the nanoindentation hardness in dry conditions. However, under boundary lubrication conditions, the friction coefficient and specific wear rate had little correlation with nanoindentation hardness, and wear behavior seemed to be influenced by other factors such as adhesion strength between the film and substrate.

  13. Depth profiling of fluorine-doped diamond-like carbon (F-DLC) film: Localized fluorine in the top-most thin layer can enhance the non-thrombogenic properties of F-DLC

    Energy Technology Data Exchange (ETDEWEB)

    Hasebe, Terumitsu [Center for Science of Environment, Resources and Energy, Keio University Faculty of Science and Technology, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan); Department of Radiology, Tachikawa Hospital, 4-2-22, Nishiki-cho, Tachikawa, Tokyo 190-8531 (Japan)], E-mail: teru_hasebe@hotmail.com; Nagashima, So [Center for Science of Environment, Resources and Energy, Keio University Faculty of Science and Technology, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan); Kamijo, Aki [Department of Transfusion Medicine, the University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Yoshimura, Taichi; Ishimaru, Tetsuya; Yoshimoto, Yukihiro; Yohena, Satoshi; Kodama, Hideyuki; Hotta, Atsushi [Center for Science of Environment, Resources and Energy, Keio University Faculty of Science and Technology, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan); Takahashi, Koki [Department of Transfusion Medicine, the University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Suzuki, Tetsuya [Center for Science of Environment, Resources and Energy, Keio University Faculty of Science and Technology, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan)

    2007-12-03

    Fluorine-doped diamond-like carbon (F-DLC) has recently drawn a great deal of attention as a more non-thrombogenic coating than conventional DLC for blood-contacting medical devices. We conducted quantitative depth profiling of F-DLC film by X-ray photoelectron spectroscopy (XPS) in order to elucidate the effects of fluorine and fluorine distribution in F-DLC film in connection with the prevention of surface blood adhesion. F-DLC films were prepared on silicon substrates using the radio frequency plasma enhanced chemical vapor deposition method, and the thickness of films was {approx} 50 nm. 50-nm-thick F-DLC film samples were etched at 10-nm thickness intervals using argon plasma, and each surface was examined by XPS. Thereafter, each etched film layer was incubated with platelet-rich plasma isolated from human whole blood, and the platelet-covered area per unit area was evaluated for each surface. XPS spectra showed the localization of doped fluorine in the top-most thin layer of the film. Platelet-covered areas represented progressively larger portions of the surfaces of deeper etched layers, corresponding to the decreasing fluorine content in such sample surfaces. These results indicate that the localized fluorine in the top-most thin layer is one of the key factors in the promotion of the non-thrombogenicity of F-DLC film.

  14. Diamond and diamond-like films for transportation applications

    Energy Technology Data Exchange (ETDEWEB)

    Perez, J.M.

    1993-01-01

    This section is a compilation of transparency templates which describe the goals of the Office of Transportation Materials (OTM) Tribology Program. The positions of personnel on the OTM are listed. The role and mission of the OTM is reviewed. The purpose of the Tribology Program is stated to be `to obtain industry input on program(s) in tribology/advanced lubricants areas of interest`. The objective addressed here is to identify opportunities for cost effective application of diamond and diamond-like carbon in transportation systems.

  15. Preparation of hydrogenated diamond-like carbon films using high-density pulsed plasmas of Ar/C2H2 and Ne/C2H2 mixture

    Science.gov (United States)

    Kimura, Takashi; Kamata, Hikaru

    2016-07-01

    Hydrogenated diamond-like carbon films are prepared using reactive high-density pulsed plasmas of Ar/C2H2 and Ne/C2H2 mixture in the total pressure range from 0.5 to 2 Pa. The plasmas are produced using a reactive high-power impulse magnetron sputtering (HiPIMS) system. A negative pulse voltage of ‑500 V is applied to the substrate for a period of 15 µs in the afterglow mode. The growth rate does not strongly depend on the type of ambient gas but it markedly increases to about 2.7 µm/h at a C2H2 fraction of 10% and a total pressure of 2 Pa with increasing C2H2 fraction. The marked increase in the growth rate means that the HiPIMS system can be regarded as a plasma source for the chemical vapor deposition process. The hardness of the films prepared by Ne/C2H2 plasmas is somewhat higher than that of the films prepared by Ar/C2H2 plasmas under the same operating conditions, and the difference becomes larger as the pressure increases. The hardness of the films prepared by Ne/C2H2 plasmas ranges between 11 and 18 GPa. In the Raman spectra, two very broad overlapping bands are assigned as the G (graphite) and D (disorder) bands. The peak position of the G band is roughly independent of the total pressure, whereas the FWHM of the G peak decreases with increasing total pressure as a whole.

  16. Tribological properties of amorphous hydrogenated (a-C:H) and hydrogen-free tetrahedral (ta-C) diamond-like carbon coatings under jatropha biodegradable lubricating oil at different temperatures

    Science.gov (United States)

    Mobarak, H. M.; Masjuki, H. H.; Mohamad, E. Niza; Kalam, M. A.; Rashedul, H. K.; Rashed, M. M.; Habibullah, M.

    2014-10-01

    The application of diamond-like carbon (DLC) coatings on automotive components is emerging as a favorable strategy to address the recent challenges in the industry. DLC coatings can effectively lower the coefficient of friction (CoF) and wear rate of engine components, thereby improving their fuel efficiency and durability. The lubrication of ferrous materials can be enhanced by a large amount of unsaturated and polar components of oils. Therefore, the interaction between nonferrous coatings (e.g., DLC) and vegetable oil should be investigated. A ball-on-plate tribotester was used to run the experiments. Stainless steel plates coated with amorphous hydrogenated (a-C:H) DLC and hydrogen-free tetrahedral (ta-C) DLC that slide against 440C stainless steel ball were used to create a ball-on-plate tribotester. The wear track was investigated through scanning electron microscopy. Energy dispersive and X-ray photoelectron spectroscopies were used to analyze the tribofilm inside the wear track. Raman analysis was performed to investigate the structural changes in the coatings. At high temperatures, the CoF in both coatings decreased. The wear rate, however, increased in the a-C:H but decreased in the ta-C DLC-coated plates. The CoF and the wear rate (coated layer and counter surface) were primarily influenced by the graphitization of the coating. Tribochemical films, such as polyphosphate glass, were formed in ta-C and acted as protective layers. Therefore, the wear rate of the ta-C DLC was lower than that of the-C:H DLC.

  17. 类金刚石薄膜光学参数反演的改进遗传算法%Improved Genetic Algorithm Inverted with Optical Constants of Diamond-Like Carbon Film

    Institute of Scientific and Technical Information of China (English)

    李建超; 苏俊宏; 徐均琪

    2011-01-01

    椭偏法测试薄膜不能直接得到薄膜的光学参数,需进行数值反演算法近似求解.采用遗传算法,借鉴竞争选择、小生境和适应值调节思想,对选择算子、变异算子、交叉算子三个重要箅子进行了适当改进,改进后算法有效防止了"早熟"现象.并搜索到了全局最优,降低了操作者对拟合模型设定初值的要求.在实践上.通过3种拟合方式的结果对比,得到了可靠的某条件下制备的类金刚石薄膜的光学常数,验证了改进遗传算法在拟合薄膜光学常数中的有效性.%Ellipsometry can not be directly tested by thin film optical parameters, which needs approximate solution method for numerical inversion.Using genetic algorithms, the selection operator, mutation operator and crossover operator are improved by drawing from competition, selection and fitness niche adjustment idea.The improved algorithm is effective in preventing the "premature" phenomenon.It searches the global optimal and reduces the requirements on the operator to set the initial value on the fitted model.In practice, by comparing the results of the three fitting methods, we gain reliable optical constants of diamond-like carbon (DLC) films prepared under certain conditions.The improved genetic algorithm is effective to fit thin film optical constants through a large number of fitting.

  18. Tribological properties of amorphous hydrogenated (a-C:H) and hydrogen-free tetrahedral (ta-C) diamond-like carbon coatings under jatropha biodegradable lubricating oil at different temperatures

    International Nuclear Information System (INIS)

    Highlights: • We tested a-C:H and ta-C DLC coatings as a function of temperature. • Jatropha oil contains large amounts of polar components that enhanced the lubricity of coatings. • CoF decreases with increasing temperature for both contacts. • Wear rate increases with increasing temperature in a-C:H and decreases in ta-C DLC. • At high temperature, ta-C coatings confer more protection than a-C:H coatings. - Abstract: The application of diamond-like carbon (DLC) coatings on automotive components is emerging as a favorable strategy to address the recent challenges in the industry. DLC coatings can effectively lower the coefficient of friction (CoF) and wear rate of engine components, thereby improving their fuel efficiency and durability. The lubrication of ferrous materials can be enhanced by a large amount of unsaturated and polar components of oils. Therefore, the interaction between nonferrous coatings (e.g., DLC) and vegetable oil should be investigated. A ball-on-plate tribotester was used to run the experiments. Stainless steel plates coated with amorphous hydrogenated (a-C:H) DLC and hydrogen-free tetrahedral (ta-C) DLC that slide against 440C stainless steel ball were used to create a ball-on-plate tribotester. The wear track was investigated through scanning electron microscopy. Energy dispersive and X-ray photoelectron spectroscopies were used to analyze the tribofilm inside the wear track. Raman analysis was performed to investigate the structural changes in the coatings. At high temperatures, the CoF in both coatings decreased. The wear rate, however, increased in the a-C:H but decreased in the ta-C DLC-coated plates. The CoF and the wear rate (coated layer and counter surface) were primarily influenced by the graphitization of the coating. Tribochemical films, such as polyphosphate glass, were formed in ta-C and acted as protective layers. Therefore, the wear rate of the ta-C DLC was lower than that of the-C:H DLC

  19. Deposition technology and properties of diamond-like carbon thin film on tappet%发动机挺柱沉积类金刚石薄膜的工艺及性能

    Institute of Scientific and Technical Information of China (English)

    黄平; 张营营; 张斌; 范梅梅; 李兴杰; 强力

    2013-01-01

    采用磁控溅射法,以Cr、Ti和石墨为靶材,Ar、N2和CH4为溅射气体,在材料为20CrMo的发动机挺柱上利用多层梯度复合技术沉积了低摩擦类金刚石(DLC)薄膜复合层CrTi/CrTiN/CrTiC/DLC.该薄膜复合层的纳米压痕硬度高达13 GPa,结合力为50 N,表面粗糙度为0.398 nm.在SRV-IV微动摩擦磨损试验机上进行耐磨损试验后,DLC复合薄膜挺柱的磨损率为渗碳挺柱的1/6.该研究技术具有自主知识产权,实现了挺柱批量化覆膜加工,并有望在发动机主要摩擦副上推广应用.%A low-friction multilayered diamond-like carbon (DLC) film with gradient structure of CrTi/CrTiN/CrTiC/DLC was deposited on tappet made of 20CrMo by magnetron sputtering of Cr,Ti,and graphite targets in Ar/N2/CH4 atmosphere.The composite thin film features hardness up to 13 GPa,bonding strength 50 N,and surface roughness 0.398 nm.The wear rate of the sputtered tappet is 1/6 of that of a carburized one after testing by SRV-IV fretting tribometer.The bulk thin film processing of tappets by using the technology with independent intellectual property rights has been realized,showing a promising use in manufacturing main friction couples of engines.

  20. Tribological properties of amorphous hydrogenated (a-C:H) and hydrogen-free tetrahedral (ta-C) diamond-like carbon coatings under jatropha biodegradable lubricating oil at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Mobarak, H.M., E-mail: mobarak.ho31@yahoo.com; Masjuki, H.H.; Mohamad, E. Niza, E-mail: edzrol@um.edu.my; Kalam, M.A.; Rashedul, H.K.; Rashed, M.M.; Habibullah, M.

    2014-10-30

    Highlights: • We tested a-C:H and ta-C DLC coatings as a function of temperature. • Jatropha oil contains large amounts of polar components that enhanced the lubricity of coatings. • CoF decreases with increasing temperature for both contacts. • Wear rate increases with increasing temperature in a-C:H and decreases in ta-C DLC. • At high temperature, ta-C coatings confer more protection than a-C:H coatings. - Abstract: The application of diamond-like carbon (DLC) coatings on automotive components is emerging as a favorable strategy to address the recent challenges in the industry. DLC coatings can effectively lower the coefficient of friction (CoF) and wear rate of engine components, thereby improving their fuel efficiency and durability. The lubrication of ferrous materials can be enhanced by a large amount of unsaturated and polar components of oils. Therefore, the interaction between nonferrous coatings (e.g., DLC) and vegetable oil should be investigated. A ball-on-plate tribotester was used to run the experiments. Stainless steel plates coated with amorphous hydrogenated (a-C:H) DLC and hydrogen-free tetrahedral (ta-C) DLC that slide against 440C stainless steel ball were used to create a ball-on-plate tribotester. The wear track was investigated through scanning electron microscopy. Energy dispersive and X-ray photoelectron spectroscopies were used to analyze the tribofilm inside the wear track. Raman analysis was performed to investigate the structural changes in the coatings. At high temperatures, the CoF in both coatings decreased. The wear rate, however, increased in the a-C:H but decreased in the ta-C DLC-coated plates. The CoF and the wear rate (coated layer and counter surface) were primarily influenced by the graphitization of the coating. Tribochemical films, such as polyphosphate glass, were formed in ta-C and acted as protective layers. Therefore, the wear rate of the ta-C DLC was lower than that of the-C:H DLC.

  1. Diamond-like coating-orientant as a promising tribological material

    International Nuclear Information System (INIS)

    Efficacy of carbon diamond-like coating (DLC) using for rubbing surfaces of lubricated friction units is analyzed. The problems connected with the effect of DLC structure on tribological behavior under lubricated conditions, as well as specific character of interaction between carbon coating and active components of tube oils are considered. A separate type of carbon coatings - coatings-orientants what provides formation of stronger boundary lube layers resulting in widening of temperature ranges of lube materials operation is also considered

  2. 纳米渗氮类金刚石碳膜的耐磨性研究%The Study of Wear Ability on Pure Titanium Coating with H-Diamond Like Carbon

    Institute of Scientific and Technical Information of China (English)

    魏广治; 尹路; 马晟利; 李慧

    2012-01-01

    目的:研究纯钛铸件镀制纳米渗氮类金刚石碳膜(N-DLC)在体外球磨实验及刷洗实验中粗糙度、表面形貌变化,为临床应用类金刚石碳膜提供理论依据.方法:铸造纯钛试件30片,分别镀制N-DLC、TiN薄膜以及空白对照后进行球磨实验和牙刷刷洗实验,通过测量摩擦系数及磨痕深度等综合评价其耐磨性,并在扫描电镜下观察表面形貌.结果:3组试件中,N-DLC镀膜的粗糙度增加值、反射率下降值最小(P<0.01),空白对照组的变化最大(P<0.01),TiN的变化值略小于N-DLC镀膜(P<0.05).扫描电镜观察空白对照表面刷痕明显,TiN和N-DLC镀膜表面未见明显刷痕,仅见有加工处理残留的细小痕迹.结论:与其他表面改性方法相比,N-DLC镀膜的表面形态受磨耗试验影响最小.%Objective: To evaluate the roughness and surface morphology of pure titanium coating with Nitrogen- diamond like carbon (N - DLC) after ball milling experiments and in vitro tooth-brushing ,for the clinical application of N - DLC to provide a theoretical basis. Methods; 30 specimens of pure titanium casting were deposited on N - DLC, TiN film and contrast group after ball milling and tooth-brushing, by measuring the friction coefficient and wear track depth evaluation of its wear resistance, and scanning electron microscope to observe the surface morphology. Results: The specimens in the three groups, N - DLC coating roughness value, minimum value of reflectance decrease (P<0. 01) , the greatest change in the control group (P<0. 01) , TiN changes in the value of slightly less than N -DLC coating (P

  3. Plasma spraying method for forming diamond and diamond-like coatings

    Science.gov (United States)

    Holcombe, Cressie E.; Seals, Roland D.; Price, R. Eugene

    1997-01-01

    A method and composition for the deposition of a thick layer (10) of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition (12) including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate (20). The softened or molten composition (18) crystallizes on the substrate (20) to form a thick deposition layer (10) comprising at least a diamond or diamond-like material. The selected composition (12) includes at least glassy carbon as a primary constituent (14) and may include at least one secondary constituent (16). Preferably, the secondary constituents (16) are selected from the group consisting of at least diamond powder, boron carbide (B.sub.4 C) powder and mixtures thereof.

  4. Silicon-incorporated diamond-like coatings for Si3N4 mechanical seals

    International Nuclear Information System (INIS)

    Amorphous silicon carbide (a-SiC) and silicon-incorporated diamond-like carbon films (DLC-Si) were evaluated as protective and friction reduction coatings onto Si3N4 rings. Unlubricated tribological tests were performed with a pin-on-disk apparatus against stainless steel pins with loads ranging from 3 to 55 N and sliding velocities from 0.2 to 1.0 m/s under ambient air and 50-60% relative humidity. At the lowest loads, a-SiC coatings present a considerable improvement with respect to the behavior of uncoated disks since the friction coefficient is reduced to about 0.2 and the system is able to run stably for thousands of meters. At higher loads, however, a-SiC coatings fail. DLC-Si-coated rings, on the other hand, presented for loads up to 10 N a steady-state friction coefficient below 0.1 and very low wear rates. The lowest steady-state mean friction coefficient value of only 0.055 was obtained with a sliding velocity of 0.5 m/s. For higher loads in the range of 20 N, the friction coefficient drops to values around 0.1 but no steady state is reached. For the highest loads of over 50 N, a catastrophic behavior is observed. Typically, wear rates below 5x10-6 and 2x10-7 mm3/N m were obtained for the ceramic rings and pins, respectively, with a load of 10 N and a sliding velocity of 0.5 m/s. Analysis of the steel pin contact surface by scanning electron microscopy (SEM)-energy dispersive X-ray spectrometry (EDS) and Auger spectroscopy revealed the formation of an adherent tribo-layer mainly composed by Si, C and O. The unique structure of DLC-Si films is thought to be responsible for the formation of the tribo-layer

  5. The effect of diamond-like carbon coating on LiNi0.8Co0.15Al0.05O2 particles for all solid-state lithium-ion batteries based on Li2S-P2S5 glass-ceramics

    Science.gov (United States)

    Visbal, Heidy; Aihara, Yuichi; Ito, Seitaro; Watanabe, Taku; Park, Youngsin; Doo, Seokgwang

    2016-05-01

    There have been several reports on improvements of the performance of all solid-state battery using lithium metal oxide coatings on the cathode active material. However, the mechanism of the performance improvement remains unclear. To better understand the effect of the surface coating, we studied the impact of diamond-like carbon (DLC) coating on LiNi0.8Co0.15Al0.05O2 (NCA) by chemical vapor deposition (CVD). The DLC coated NCA showed good cycle ability and rate performance. This result is further supported by reduction of the interfacial resistance of the cathode and electrolyte observed in impedance spectroscopy. The DLC layer was analyzed by transmission electron microscopy electron energy loss spectroscopy (TEM-EELS). After 100 cycles the sample was analyzed by X-ray photo spectroscopy (XPS), and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). These analyses showed that the thickness of the coating layer was around 4 nm on average, acting to hinder the side reactions between the cathode particle and the solid electrolyte. The results of this study will provide useful insights for understanding the nature of the buffer layer for the cathode materials.

  6. Tribological properties and structural investigation of Diamond-like nano-composites

    International Nuclear Information System (INIS)

    Diamond-Like Nano composites (DylynTM) are a new family of hard amorphous coatings combining high hardness, high elasticity, low friction and good adhesion on a variety of substrates. Mechanical properties of several DylynTM films and metal-doped DylynTM films have been investigated using nano-indentation and ball-on-disk measurements. Nano hardness up to 17 GPa is reported. The coefficient of friction, measured in air at 50% relative humidity and using a steel ball with 10 N normal load, can be tailored to be typically 0.05 - 0.07. This low-friction behaviour opens up applications of these films as hard, self-lubricating, low-friction coatings. Structural characterization has been performed using Grazing Incidence X-Ray Diffraction (GIXRD), X-ray Photoelectron Spectroscopy (XPS), Auger Electron Spectroscopy (AES), Rutherford Backscattering Spectroscopy (RBS) and Elastic Recoil Detection (ERD). X-ray studies indicate that the films are completely amorphous. XPS shows that the films consist mainly of a C-based and a Si-O network. AES measurements yield spectra comparable to diamond-like carbon (DLC) due to the presence of sp3-bonded C. Finally, atomic concentrations, including the H content, have been determined with RBS and ERD. (author). 4 refs., 2 figs

  7. Diamond-like carbon film on 20 CrNiMo steel prepared by hollow-cathode glow discharge%20CrNiMo钢表面空心阴极辉光放电制备类金刚石膜

    Institute of Scientific and Technical Information of China (English)

    陈飞; 陈家庆; 周海; 张跃飞

    2011-01-01

    在真空炉内以石墨为电极,利用空心阴极辉光放电在20CrNiMo上成功地沉积了类金刚石(Diamond-like carbon,DLC)薄膜.利用激光拉曼(Baman)光谱分析了所制备DLC薄膜的结构;利用原子力显微镜(AFM)分析了DLC薄膜的表面形貌;利用划痕仪测量了DLC薄膜与基体的结合力并用扫描电子显微镜(SEM)观察了划痕形貌;利用球-盘摩擦磨损实验仪对DLC薄膜的耐磨性能进行了研究.结果表明:在本实验工艺条件下沉积的类金刚石薄膜厚度约为0.6μm,薄膜均匀且致密,表面粗糙度Ra为7~8 nm.类金刚石薄膜与基体结合较紧密,临界载荷达到52 N.DLC薄膜具有优良的减摩性,20CrNiMo表面沉积DLC薄膜后摩擦系数为0.15,较20CrNiMo基体的摩擦系数0.50明显减小,耐磨性能得到提高.%Diamond-like carbon (DLC) thin film was deposited on the sudace of 20CrNiMo ahoy by hollow cathode glow discharge technique. High purity graphite was selected as the cathode and Ar as working gas. The structure of the DLC thin film was analyzed by laser Raman spectroscopy. Surface morphology of the film was observed by atomic force microscope ( AFM ). The adhesion between the DLC thin film and the substrate was investigated with scratch testing. The morphology of the scratch was observed by scanning electron microscopy(SEM). Friction and wear behavior of the DLC thin film under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results show that it is feasible to prepare a DLC thin film of 0. 6 μm thick by this experimental process. The surface roughness Ra of the film is 7-8 nm. The DLC thin film has a good adhesion with critical load of 52 N by scratch testing. Excellent friction and wear-resistant behavior of the film is observed. Friction coefficient of the 20CrNiMo substrate is about 0.50 under dry sliding against steel, while the DLC thin film exhibited much lower friction coefficient of 0. 15 under the same testing condition.

  8. Tribology of diamond-like carbon films fundamentals and applications

    CERN Document Server

    Donnet, Christophe

    2007-01-01

    Despite being in the spotlight for a very long time; there is no such book that is dedicated to the Tribology and applications of DLC films. Both scientifically and industrially, interest in these films has grown rapidly in recent years and this trend is expected to grow even further with increasing industrial applications. This book contains some of the most relevant and fundamental information on the Tribology and applications of DLC films. It also provides reliable and up-to-date information on different DLC coatings and their tribological properties which are available for use in various i

  9. Structure and Properties of Cr-containing Hydrogenated Diamond-like Carbon Films Deposited by DC Filtered Cathodic Vacuum Arc Technology%磁过滤直流真空阴极弧制备含铬类金刚石膜的结构及其性能研究

    Institute of Scientific and Technical Information of China (English)

    祝土富; 沈丽如; 徐桂东; 金凡亚

    2009-01-01

    采用磁过滤直流真空阴极弧沉积技术在单晶硅片、载玻片、不锈钢片基体上制备了含铬类金刚石(Cr-DLC)膜.用光学显微镜、椭偏仪、分光光度计、X射线光电子能谱(XPS)、X射线衍射能谱(XRD)、Raman光谱、纳米硬度计、摩擦磨损仪、洛氏硬度计检测了薄膜的组分结构、光学、力学等相关特性.结果表明,硅片上的薄膜厚度为47.6nm,碳含量为89%,s p~3键占碳含量的55.15%.不锈钢片上的薄膜具有典型的DLC膜Raman光谱特征,在空气中的摩擦系数约为0.1,耐磨性能优良,膜与基体的结合性能良好.%Cr-containing hydrogenated diamond-like carbon (Cr-DLC) films were deposited on stainless steel plate, monocrystalline silicon wafer and microscope slide glass by DC filtered cathodic vacuum arc technology. The composition, structure and properties of Cr-DLC films were investigated by spec-troscopic ellipsometer, X-ray photoelectron spectroscopy(XPS), powder X-ray diffraction(XRD), spectrophotometer, Raman spectroscopy, nanoindenter, ball-on-disk tribometer, Rockwell apparatus and optical microscope. It was shown that the content of C is 89% in the film deposited on silicon wa-fer and the content of sp~3 bonding carbon atoms in the C element is 55.15%. The Raman spectra of the film deposited on stainless steel plate has the typical characteristics of DLC. The hardness and elastic modulus of the film deposited on stainless steel plate are 16.01 GPa and 142.72 GPa. The fric-tion coefficient of the film deposited on stainless steel plate is about 0.1, the film also exhibits excel-lent wear resistance and the adhesion to substrate is very well.

  10. UV Raman and XPS studies of hydrogenous diamond-like carbon films prepared by PECVD%等离子体增强化学气相沉积法制备含氢类金刚石膜的紫外Raman光谱和X射线光电子能谱研究

    Institute of Scientific and Technical Information of China (English)

    杨发展; 沈丽如; 王世庆; 唐德礼; 金凡亚; 刘海峰

    2013-01-01

    利用脉冲辉光放电的方法,在硅片上采用不同的沉积工艺制备了含氢类金刚石膜层,并采用Raman光谱和X射线光电子能谱(XPS)对膜层进行表征.用Raman光谱仪在波长为325 nm的紫外光源的激励下观察膜层的键结构.紫外Raman光谱对含氢类金刚石膜是非常有用的,它能有效避免可见光Raman光谱测量时的荧光干扰,清晰地得到膜层的D峰和G峰.同时利用XPS分析得到膜层的sp3键含量,并与Raman光谱所得数据进行比较.通过Raman光谱和XPS分析可以发现,在紫外光源的激励下,膜层的G峰峰位向高频移方向移动,G峰峰位、I(D)/I(G),G峰半高宽和sp3键含量之间存在一定的关系.%The hydrogenous diamond-like carbon (DLC) films deposited on Si substrates using pulsed glow discharge method are investigated using Raman spectroscopy and X-ray photoelectron spectroscopy method. The UV Raman spectrum for excitation wavelength is 325 nm. UV Raman is particularly useful for hydrogenous DLC, as it gives clear measurements in the D and G peak spectral region even for highly hydrogenated samples, for which the visible Raman spectra are overshadowed by photoluminescence. The sp3 bonding of hydrogenous DLC film can be effectively studied by X-ray photoelectron spectroscopy method, and the data from the X-ray photo-electron spectroscopy method are compared with Raman results. It is found that G peak shows a shift to ward a higher wave under UV excitation. For the G peak, I(D)/I(G), G-FWHM and sp3, there exists a relationship among them.

  11. Diamond-like nanocomposite coatings for LIGA-fabricated nickel alloy parts.

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Somuri V.; Scharf, Thomas W.

    2005-03-01

    A commercial plasma enhanced chemical vapor deposition (PECVD) technique with planetary substrate rotation was used to apply a thin (200-400 nm thick) conformal diamond-like carbon (DLC) coating (known as a diamond-like nanocomposite (DLN)) on LIGA fabricated Ni-Mn alloy parts. The PECVD technique is known to overcome the drawbacks associated with the line-of-sight nature of physical vapor deposition (PVD) and substrate heating inherent with traditional chemical vapor deposition (CVD). The purpose of the present study is to characterize the coverage, adhesion, and tribological (friction and wear) behavior of DLN coatings applied to planar and sidewall surfaces of small featured LIGA Ni-Mn fabricated parts, e.g. 280 {micro}m thick sidewalls. Friction and wear tests were performed in dry nitrogen, dry air, and air with 50% RH at Hertzian contact pressures ranging from 0.3 to 0.6 GPa. The friction coefficient of bare Ni-Mn alloy was determined to be 0.9. In contrast, low friction coefficients ({approx}0.02 in dry nitrogen and {approx}0.2 in 50% RH air) and minimal amount of wear were exhibited for the DLN coated LIGA Ni-Mn alloy parts and test coupons. This behavior was due to the ability of the coating to transfer to the rubbing counterface providing low interfacial shear at the sliding contact; resultantly, coating one surface was adequate for low friction and wear. In addition, a 30 nm thick titanium bond layer was determined to be necessary for good adhesion of DLN coating to Ni-Mn alloy substrates. Raman spectroscopy and cross-sectional SEM with energy dispersive x-ray analysis revealed that the DLN coatings deposited by the PECVD with planetary substrate rotation covered both the planar and sidewall surfaces of LIGA fabricated parts, as well as narrow holes of 300 {micro}m (0.012 inch) diameter.

  12. Thermal stability of diamond-like carbon–MoS2 thin films in different environments

    International Nuclear Information System (INIS)

    Diamond-like carbon (DLC) based coatings are ideal for low friction and wear resistant applications. For those tribological applications, the coatings may expose to high temperature environments. Therefore, the thermal stability of the coating is very important for its long-term performance. In this work, DLC–MoS2 composite thin films were synthesized using biased target ion beam deposition technique in which MoS2 was produced by sputtering a MoS2 target using Ar ion beams while DLC was deposited by an ion source with CH4 gas as carbon source. DLC films without MoS2 deposited under similar conditions were used as reference samples. After the deposition, DLC and DLC–MoS2 thin films were heat-treated in ambient air and low pressure environments at different temperatures ranging from 100 to 600 °C for 2 h. The effect of annealing on the structure, mechanical and tribological properties of the resulting films were studied by means of Raman spectroscopy, X-ray absorption near edge structure, scanning electron microscopy, nanoindentation, and ball-on-disk testing. The results showed that the structure, hardness, Young's modulus, friction coefficient and wear coefficient of the DLC films were stable up to 200 °C annealing in air and 300 °C in low pressure. At higher temperature, the annealing led to the transformation of sp3 to sp2, which degraded the mechanical and tribological properties of the thin films. Comparing with the DLC films, the DLC–MoS2 thin films showed a slower rate of graphitization and higher structure stability throughout the range of annealing temperatures, indicating a relatively higher thermal stability. - Highlights: • Thermal stability of diamond-like carbon (DLC) and DLC–MoS2 films were evaluated. • DLC–MoS2 films can be synthesized by biased target ion beam deposition technique. • Comparing with DLC films, the DLC–MoS2 thin films showed higher thermal stability. • DLC–MoS2 film is thermally stable up to 400 °C in

  13. Diamond-like Carbon Thin Films Deposited on Ti6Al4V Alloy Surface by Plasma Gun at Atmospheric Pressure%钛合金表面大气压等离子体枪制备类金刚石薄膜

    Institute of Scientific and Technical Information of China (English)

    陈飞; 周海; 张跃飞; 吕反修

    2012-01-01

    在大气下,采用大气压介质阻挡放电(DBD)等离子体枪在低温下<350℃),以甲烷为单体,氩气为工作气体,在Ti6Al4V钛合金表面制备一层类金刚石薄膜(DLC),以期改善钛合金表面摩擦学性能.利用激光拉曼(Raman)光谱和X射线光电子能谱(XPS)分析了所制备DLC薄膜的结构;利用扫描电子显微镜(SEM)观察DLC薄膜的表面形貌;利用划痕仪测量了DLC薄膜与基体的结合力;利用球-盘摩擦磨损实验仪对DLC薄膜的耐磨性能进行了研究.结果表明:在本实验工艺条件下沉积的类金刚石薄膜厚度约为1.0 μm,薄膜均匀且致密,表面粗糙度Ra为13.23 nm.类金刚石薄膜与基体结合力的临界载荷达到31.0N.DLC薄膜具有优良的减摩性,Ti6Al4V表面沉积DLC薄膜后摩擦系数为0.15,较Ti6Al4V基体的摩擦系数0.50明显减小,耐磨性能得到提高.%At atmospheric pressure, diamond-like carbon (DLC) thin films were deposited on the T16A14V alloy surface by a DBD plasma gun at low temperature (<350℃), with CH4 as a precursor and Ar as dilution gas. The structure of the DLC thin film was analyzed by Laser Raman spectroscope and X-ray photoelectron spectroscopy. The surface morphology was observed through scanning electron microscopy. The adhesion between the DLC thin film and the substrate was investigated with the scribe testing. The friction and wear behavior of the DLC thin films under dry sliding against GCrlS steel was evaluated on a ball-on-disc test rig. The results show that it is feasible to prepare a DLC thin film of 1.0 um thickness by a plasma gun. The film is uniform and dense and the surface roughness R. Is about 13.23 nm. The critical load of adhesion force between the DLC thin film and the substrate is 31.0 N. It has been found that the DLC thin film has excellent friction- and wear-resistant behavior. The friction coefficient of the Ti6A14V substrate is about 0.50 under dry sliding against steel, while the DLC thin

  14. 组织工程化类金刚石膜复合材料与人血管内皮细胞的相容性研究%Biocompatibility between tissue-engineering diamond-like carbon film and human vascular endothelial cells

    Institute of Scientific and Technical Information of China (English)

    程光存; 严中亚; 罗乐; 方晓东; 沙自明

    2009-01-01

    OBJECTIVE: To verify the biocompatibility between diamond-like carbon (DLC) film and human vascular endothelial cells and to provide evidences for construction of artificial mechanical valve prosthesis. METHODS: Nanophase DLC film was deposited using pulse laser deposition, while vascular endothelial cells derived from human umbilical vein was cultured with nanophase DLC film in vitro. Cell growth and adhesion were observed under inverted microscope, and cell proliferation was measured with MIT method. In addition, levels of nitric oxide (NO) and prostacyclin (PGI2) were measured in the DLC group and blank control group in order to evaluate their activities. RESULTS: Adhesion, proliferation, and growth of vascular endothelial cells derived from human umbilical vein were great on the surface of nanophase DLC film. There were no significant differences in the levels of NO and PGI2 between DLC group and blank control group (P > 0.05), showing that nanophase DLC film had no effect on activity of vascular endothelial cells derived from human umbilical vein. CONCLUSION: Nanophase DLC film has a good biocompatibility, and it can become an ideal material of tissue-engineering artificial mechanical valve prosthesis.%目的:验证纳米相类金刚石薄膜复合材料与人血管内皮细胞相容性,为组织上程化机械瓣膜材料的构建提供依据.方法:利用脉冲激光沉积法在人工心脏机械瓣膜上沉积纳米相类金刚石薄膜,将人脐静脉血管内皮细胞与纳米相类金刚石薄膜复合材料体外复合培养.倒置显微镜及扫描电镜观察细胞在材料表面的生长、附着情况;MTT法检测细胞在材料上增殖情况;同时分别测定人脐静脉血管内皮细胞在类金刚石溥膜材料和空白对照组中一氧化氮及前列环素分泌水平,以评价其活性.结果:人脐静脉血管内皮细胞能在纳米相类金刚石薄膜复合材料上良好地黏附、增殖、生长.人脐静脉血管内皮细胞分泌

  15. Effects of pretreatment and post-annealing on the field emission property of diamond-like carbon grown on a titanium/silicon substrate%利用前后处理技术改进钛/硅基板上的类金刚石场发射特性

    Institute of Scientific and Technical Information of China (English)

    黄柏仁; 叶忠信; 李世鸿; 汪岛军; 陈昆歧

    2008-01-01

    采用微波等离子体化学气相沉积系统存钛/硅基板上沉积类金刚石薄膜,并利用拉曼光谱仪、扫瞄式电子显微镜及原子力显微镜研究了氢等离子体前处理及快速退火后处理对类金刚石薄膜场发射特性之影响.在沉积类金刚石薄膜之前,钛/硅基板使用了两种前处理技术:第一种为研磨金刚石粉末,第二种为研磨金刚石粉末后外加氢等离子体刻蚀处理.成长类金刚石薄膜后进行快速退火处理.发现不论是氢等离子体前处理还是快速退火后处理皆能改善场发射特性,其中经退火后处理的场发射特性比氢等离子体前处理的场发射特性改善更明显.其因之一在于快速退火后处理可在类金刚石薄膜表而形成sp2丛聚,提供了很多的场发射子,也同时增加了表面粗糙度;另一个原因可能是在快速退火后处理期间会使类金刚石薄膜进一步石墨化,因而提供了许多电子在通过类金刚石薄膜时的传输路径.研究结果表明:利用适当的前后处理技术可改进类金刚石薄膜的场发射特性,进而做为冷阴极材料之应用.%Diamond-like carbon (DLC) films were deposited on titanium/silicon substrates with the help of the micro-wave plasma chemical vapor deposition (CVD) method with At, H2, and CH4 as a mixed gas source. Titanium/silicon substrates were polished by diamond powder and etched by hydrogen ( H2 ) plasma, prior to deposition. After deposi-tion, rapid thermal annealing (RTA) was used as a post-treatment. The effects of hydrogen plasma pretreatment and RTA post-treatment on the electron field emission characteristics of the DLC films was examined and correlated by Ra-man scattering, average surface roughness, and surface morphology. It is found that both treatments can improve the field emission characteristics of DLC films. However, RTA post-treatment demonstrates a more pronounced effect on the enhancement of field emission than does the

  16. Julia sets and complex singularities in diamond-like hierarchical Potts models

    Institute of Scientific and Technical Information of China (English)

    QIAO; Jianyong

    2005-01-01

    We study the phase transition of the Potts model on diamond-like hierarchical lattices. It is shown that the set of the complex singularities is the Julia set of a rational mapping. An interesting problem is how are these singularities continued to the complex plane. In this paper, by the method of complex dynamics, we give a complete description about the connectivity of the set of the complex singularities.

  17. Thermal stability of diamond-like carbon–MoS{sub 2} thin films in different environments

    Energy Technology Data Exchange (ETDEWEB)

    Niakan, H., E-mail: hamid.niakan@usask.ca [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Zhang, C. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Hu, Y. [Canadian Light Source, 101 Perimeter Road, Saskatoon, SK S7N 0X4 (Canada); Szpunar, J.A.; Yang, Q. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada)

    2014-07-01

    Diamond-like carbon (DLC) based coatings are ideal for low friction and wear resistant applications. For those tribological applications, the coatings may expose to high temperature environments. Therefore, the thermal stability of the coating is very important for its long-term performance. In this work, DLC–MoS{sub 2} composite thin films were synthesized using biased target ion beam deposition technique in which MoS{sub 2} was produced by sputtering a MoS{sub 2} target using Ar ion beams while DLC was deposited by an ion source with CH{sub 4} gas as carbon source. DLC films without MoS{sub 2} deposited under similar conditions were used as reference samples. After the deposition, DLC and DLC–MoS{sub 2} thin films were heat-treated in ambient air and low pressure environments at different temperatures ranging from 100 to 600 °C for 2 h. The effect of annealing on the structure, mechanical and tribological properties of the resulting films were studied by means of Raman spectroscopy, X-ray absorption near edge structure, scanning electron microscopy, nanoindentation, and ball-on-disk testing. The results showed that the structure, hardness, Young's modulus, friction coefficient and wear coefficient of the DLC films were stable up to 200 °C annealing in air and 300 °C in low pressure. At higher temperature, the annealing led to the transformation of sp{sup 3} to sp{sup 2}, which degraded the mechanical and tribological properties of the thin films. Comparing with the DLC films, the DLC–MoS{sub 2} thin films showed a slower rate of graphitization and higher structure stability throughout the range of annealing temperatures, indicating a relatively higher thermal stability. - Highlights: • Thermal stability of diamond-like carbon (DLC) and DLC–MoS{sub 2} films were evaluated. • DLC–MoS{sub 2} films can be synthesized by biased target ion beam deposition technique. • Comparing with DLC films, the DLC–MoS{sub 2} thin films showed higher

  18. Modulation polarimetry of full internal reflection, broken by diamond-like films

    Directory of Open Access Journals (Sweden)

    Maksimenko L. S.

    2013-02-01

    Full Text Available This article presents research results on diamond-like films produced under different technological conditions. The parameter ρ — polarization difference — has been introduced. It has been found from spectral features of the parameter ρ that the interaction of electromagnetic radiation with the electronic system of specimens, which occurs in the used spectral range, consists of local and polariton surface resonances, differing in frequencies and times of relaxations. The autors concluded that the correlation in resonance intensity is defined by the structural characteristics of the specimens. These results show that modulation polarimetry is a perspective technique for diagnostics of the structural homogeneity of composite nanocluster films.

  19. Tritrichomonas foetus adhere to superhydrophilic vertically aligned multi-walled carbon nanotube surface

    Energy Technology Data Exchange (ETDEWEB)

    Moreira Machado, Susane [Laboratorio de Biologia Celular e Tecidual, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, 12244-000, Sao Jose dos Campos, SP (Brazil); Oliveira Lobo, Anderson, E-mail: loboao@yahoo.com [Laboratorio de Nanotecnologia Biomedica (NanoBio), Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, SP (Brazil); Laboratorio de Espectroscopia Vibracional Biomedica, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Avenida Shishima Hifumi, 2911, CEP 12244-000, Sao Jose dos Campos, SP (Brazil); Bueno Loureiro Sapucahy, Ariel [Laboratorio de Biologia Celular e Tecidual, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, 12244-000, Sao Jose dos Campos, SP (Brazil); Marciano, Fernanda Roberta [Laboratorio de Nanotecnologia Biomedica (NanoBio), Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, Sao Jose dos Campos, 12244-000, SP (Brazil); Laboratorio de Espectroscopia Vibracional Biomedica, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Avenida Shishima Hifumi, 2911, CEP 12244-000, Sao Jose dos Campos, SP (Brazil); Corat, Evaldo Jose [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010 SP (Brazil); Soares da Silva, Newton [Laboratorio de Biologia Celular e Tecidual, Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi 2911, 12244-000, Sao Jose dos Campos, SP (Brazil)

    2011-10-10

    For the first time, we show that Tritrichomonas foetus can adhere on superhydrophilic vertically aligned carbon nanotubes (VACNT) films. Scanning electron microscopy shows an unusual adhesion with a higher membrane filopodium projection in all directions, directly attached to superhydrophilic VACNT tips. Highlights: {yields} This is a new method to study the T. foetus adhesion mechanism. {yields} SEM images and interfacial adhesion force show a high adhesion level. {yields} It is very important for future understanding mechanism adhesion and protein expression.

  20. Deposition and characterization of diamond-like nanocomposite coatings grown by plasma enhanced chemical vapour deposition over different substrate materials

    Indian Academy of Sciences (India)

    Awadesh Kr Mallik; Nanadadulal Dandapat; Prajit Ghosh; Utpal Ganguly; Sukhendu Jana; Sayan Das; Kaustav Guha; Garfield Rebello; Samir Kumar Lahiri; Someswar Datta

    2013-04-01

    Diamond-like nanocomposite (DLN) coatings have been deposited over different substrates used for biomedical applications by plasma-enhanced chemical vapour deposition (PECVD). DLN has an interconnecting network of amorphous hydrogenated carbon and quartz-like oxygenated silicon. Raman spectroscopy, Fourier transform–infra red (FT–IR) spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) have been used for structural characterization. Typical DLN growth rate is about 1 m/h, measured by stylus profilometer. Due to the presence of quartz-like Si:O in the structure, it is found to have very good adhesive property with all the substrates. The adhesion strength found to be as high as 0.6 N on SS 316 L steel substrates by scratch testing method. The Young’s modulus and hardness have found to be 132 GPa and 14.4 GPa, respectively. DLN coatings have wear factor in the order of 1 × 10-7 mm3/N-m. This coating has found to be compatible with all important biomedical substrate materials and has successfully been deposited over Co–Cr alloy based knee implant of complex shape.

  1. On axisymmetric/diamond-like mode transitions in axially compressed core-shell cylinders

    Science.gov (United States)

    Xu, Fan; Potier-Ferry, Michel

    2016-09-01

    Recent interests in curvature- and stress-induced pattern formation and pattern selection motivate the present study. Surface morphological wrinkling of a cylindrical shell supported by a soft core subjected to axial compression is investigated based on a nonlinear 3D finite element model. The post-buckling behavior of core-shell cylinders beyond the first bifurcation often leads to complicated responses with surface mode transitions. The proposed finite element framework allows predicting and tracing these bifurcation portraits from a quantitative standpoint. The occurrence and evolution of 3D instability modes including sinusoidally deformed axisymmetric patterns and non-axisymmetric diamond-like modes will be highlighted according to critical dimensionless parameters. Besides, the phase diagram obtained from dimensional analyses and numerical results could be used to guide the design of core-shell cylindrical systems to achieve the desired instability patterns.

  2. 磁控溅射Al靶功率对类金刚石薄膜结构和摩擦学性能的影响%Effect of Al Target Power of Magnetron Sputtering on the Structure and Tribological Properties of Diamond-like Carbon Films

    Institute of Scientific and Technical Information of China (English)

    周升国; 王立平; 薛群基

    2011-01-01

    本文采用中频磁控溅射金属Al靶,以CH4为反应气体,通过调整Al靶溅射功率,在p(100)单晶硅片和不锈钢基底上成功制备出不同Al含量的Al/a-C∶H纳米复合薄膜.并利用HR-TEM、XPS、纳米压痕仪和摩擦磨损试验机等手段分析和研究了Al/a-C∶H薄膜的结构、机械及摩擦学性能.结果表明:金属Al以纳米晶颗粒形式镶嵌在非晶碳网络中,使得所制备Al/a-C∶H薄膜呈现出典型的纳米晶/非晶复合结构;同时,Al掺杂促进了薄膜中sp2杂化碳形成,且有效地释放残余内应力.Al靶溅射功率为800W时所制备的Al/a-C∶H薄膜具有结构致密、内应力低、硬度高的特性;在大气环境中,该薄膜与Si3N4陶瓷球干摩擦时显示出优越的摩擦学性能,其摩擦系数约为0.055,磨损率约为2.9×10-16m3/(N·m).%Aluminum/amorphous hydrogenated carbon (Al/a-C: H) nanocomposite thin films were deposited on silicon p( 100) wafer and stainless steel substrates by magnetron sputtering of aluminum in an argon and methane atmosphere with different Al target power. The composition, microstructure, mechanical and tribological properties of composite films were systemically investigated by HR - TEM, XPS, nano - indenter and tribo - tester. The results showed that the Al nanocrystallites could be easily formed in the amorphous carbon matrix, the sp2 hybrid carbon was increased as the Al was embedded into the films, and Al - doping could relax the internal stress whilst keeping high hardness of as - deposited films. The film containing 4.7 % Al prepared by target power of 800 W exhibited a high hardness about 16.5 Cpa, a low internal stress about 0.62 Gpa, a low friction coefficient about 0.055 and a low wear rate about 2.9 × 10-16 m3/(N ? M) in the ambient atmosphere.

  3. Formation of an adherent polyacrylonitrile/carbon nanotubes composite film onto a polyacrylonitrile brush electrografted on copper.

    Science.gov (United States)

    Vast, L; Rochez, O; Azoulay, L; Fonseca, A; Nagy, J B; Deniau, G; Palacin, S; Delhalle, J; Mekhalif, Z

    2007-10-01

    An adherent polymer film based on a composite of polyacrylonitrile/multiwall carbon nanotubes (PAN/MWNTs) have been elaborated on a copper substrate. The first layer is an electrografted PAN brush on which of a subsequent layer of PAN/carbon nanotubes composite has been deposited by simple dipping from solution in dimethylformamide (DMF). MWNTs have been previously chemically functionalized with 3-cyanopropyltrichlorosilane to promote de-bundling and homogeneous dispersion of the carbon nanotubes in the composite. PMID:18330148

  4. Simulations on Various Lubrication Boundaries between Diamond-like Carbon Films

    Institute of Scientific and Technical Information of China (English)

    LAN Huiqing; KATO Takahisa

    2011-01-01

    Molecular dynamics(MD)simulations were used to study a sliding friction process between DLC films on various boundary conditions.The experimental results revealed that,in the absence of a lubricant,a transfer film between the DLC films was formed.In contrast,when the oil or water lubricants were added to lubricate between the DLC films,a boundary lubrication layer was found.The friction forces on the water and oil lubrication were almost the same,but the friction force in the absence of a lubricant was larger than those on the water and oil lubrication.The conclusions were in good agreement with the experiments.

  5. Surface modification of diamond-like carbon films with protein via polydopamine inspired coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tao Caihong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Middle Road 18th, Lanzhou 730000 (China); China and Graduate University of Chinese Academy of Sciences, Beijing 100080 (China); Yang Shengrong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Middle Road 18th, Lanzhou 730000 (China); Zhang Junyan, E-mail: zhangjunyan@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Middle Road 18th, Lanzhou 730000 (China); Wang Jinqing [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Middle Road 18th, Lanzhou 730000 (China)

    2009-10-15

    In this paper, we report a facile two-step approach to immobilize proteins onto DLC surfaces. The first step was a simple immersion of DLC in a solution of dopamine. Polydopamine was deposited on DLC as a stable anchor to present protein molecules. Then the protein ad-layer was deposited on it. The chemical components of the modified DLC surfaces were characterized by Fourier transform infrared spectra and X-ray photoelectron spectroscopy. The biocompatibility of it was evaluated in vitro by the tetrazolium salt method. And it was indicated that the BSA modified surface had good haemocompatibility properties, and was cytocompatible to PC-12 cells.

  6. In Vitro Durability - Pivot bearing with Diamond Like Carbon for Ventricular Assist Devices

    OpenAIRE

    de Sá, Rosa Corrêa Leoncio; Airoldi, Vladimir Jesus Trava; Leão, Tarcísio Fernandes; da Silva, Evandro Drigo; da Fonseca, Jeison Willian Gomes; da Silva, Bruno Utiyama; Leal, Edir Branzoni; Moro, João Roberto; de Andrade, Aron José Pazin; Bock, Eduardo Guy Perpétuo

    2015-01-01

    Institute Dante Pazzanese of Cardiology (IDPC) develops Ventricular Assist Devices (VAD) that can stabilize the hemodynamics of patients with severe heart failure before, during and/or after the medical practice; can be temporary or permanent. The ADV's centrifugal basically consist of a rotor suspended for system pivoting bearing; the PIVOT is the axis with movement of rotational and the bearing is the bearing surface. As a whole system of an implantable VAD should be made of long-life bioma...

  7. Surface modification of diamond-like carbon films with protein via polydopamine inspired coatings

    International Nuclear Information System (INIS)

    In this paper, we report a facile two-step approach to immobilize proteins onto DLC surfaces. The first step was a simple immersion of DLC in a solution of dopamine. Polydopamine was deposited on DLC as a stable anchor to present protein molecules. Then the protein ad-layer was deposited on it. The chemical components of the modified DLC surfaces were characterized by Fourier transform infrared spectra and X-ray photoelectron spectroscopy. The biocompatibility of it was evaluated in vitro by the tetrazolium salt method. And it was indicated that the BSA modified surface had good haemocompatibility properties, and was cytocompatible to PC-12 cells.

  8. The role of substrate plasticity on the tribological behavior of diamond-like nanocomposite coatings

    International Nuclear Information System (INIS)

    Finite-element modeling (FEM) was used to predict the contact stress at which the transition from elastic to plastic deformation occurs in a metallic substrate underneath a hard tribological coating. Using model systems of diamond-like nanocomposite (DLN) coatings on electroformed Ni, NiMn alloy and Inconel 718, friction measurements were made at contact stresses ranging from 540 to 1720 MPa. Cross-sections of wear scars suitable for visualization of friction-induced plastic deformation in the substrate were prepared by focused ion beam microscopy and analyzed by electron backscatter diffraction. At contact stresses below the FEM-predicted elastic-plastic limit, the coefficient of friction decreased linearly with increase in contact stress, suggesting that interfacial shear is the major mechanism of friction in DLN. Contact stresses above the FEM-predicted elastic-plastic limit resulted in plastic deformation of the metallic substrate, and in extreme cases fracture and removal of the coating resulting in a sudden increase in friction

  9. The role of substrate plasticity on the tribological behavior of diamond-like nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Jungk, J.M.; Michael, J.R. [Sandia National Laboratories, Albuquerque, NM 87185-0889 (United States); Prasad, S.V. [Sandia National Laboratories, Albuquerque, NM 87185-0889 (United States)], E-mail: svprasa@sandia.gov

    2008-05-15

    Finite-element modeling (FEM) was used to predict the contact stress at which the transition from elastic to plastic deformation occurs in a metallic substrate underneath a hard tribological coating. Using model systems of diamond-like nanocomposite (DLN) coatings on electroformed Ni, NiMn alloy and Inconel 718, friction measurements were made at contact stresses ranging from 540 to 1720 MPa. Cross-sections of wear scars suitable for visualization of friction-induced plastic deformation in the substrate were prepared by focused ion beam microscopy and analyzed by electron backscatter diffraction. At contact stresses below the FEM-predicted elastic-plastic limit, the coefficient of friction decreased linearly with increase in contact stress, suggesting that interfacial shear is the major mechanism of friction in DLN. Contact stresses above the FEM-predicted elastic-plastic limit resulted in plastic deformation of the metallic substrate, and in extreme cases fracture and removal of the coating resulting in a sudden increase in friction.

  10. Lanthanum carbonate oral powder: satisfaction, preference and adherence in French and Spanish patients with end-stage renal disease

    Science.gov (United States)

    Keith, Michael; de Sequera, Patricia; Clair, François; Pedersini, Riccardo

    2016-01-01

    Background Phosphate binders, such as lanthanum carbonate, control elevated serum-phosphate levels in patients with end-stage renal disease (ESRD). Lanthanum carbonate is available in oral powder and tablet form. The aim of this survey was to investigate satisfaction with, preference for, and adherence to lanthanum carbonate oral powder in patients with ESRD. Scope Patients from France and Spain who had been taking lanthanum carbonate powder for at least 4 weeks, and who had experience of other phosphate binders of any formulation, were asked to complete an online or telephone survey. Treatment satisfaction was measured using the Treatment Satisfaction Questionnaire for Medication-9; preference was measured using 5-point Likert scale agreement ratings; and adherence was measured using the Morisky Medication Adherence Scale-4. Data were evaluated using bivariate analyses. Findings Overall, 160 patients participated (80 per country). Lanthanum carbonate powder was reported to have a higher effectiveness rating (psubject to change over time. Although most participants completed the online survey in this study, a telephone survey was used for individuals who could not access the online version; if only one method of data recording had been used, there may have been reduced variation in responses. Conclusion Patients with ESRD report increased satisfaction with and preference for lanthanum carbonate powder over other formulations, suggesting that lanthanum carbonate powder is more convenient and easier to use than other formulations. PMID:27803726

  11. Copper-based diamond-like ternary semiconductors for thermoelectric applications

    Science.gov (United States)

    Skoug, Eric John

    Heightened global concern over greenhouse gas emissions has led to an increased demand for clean energy conversion technologies. Thermoelectric materials convert directly between thermal and electrical energy and can increase the efficiency of existing processes via waste heat recovery and solid-state climate control applications. The conversion efficiency of available thermoelectric materials and the devices comprised of them is unfortunately quite low, and thus new materials must be developed in order for thermoelectrics to keep pace with competing technologies. One approach to increasing the conversion efficiency of a given material is to decrease its lattice thermal conductivity, which has traditionally been accomplished by introducing phonon scattering centers into the material. These scattering centers also tend to degrade electronic transport in the material, thereby minimizing the overall effect on the thermoelectric performance. The purpose of this work is to develop materials with inherently low lattice thermal conductivity such that no extrinsic modifications are required. A novel approach in which complex ternary semiconductors are derived from well-known binary or elemental semiconductors is employed to identify candidate materials. Ternary diamond-like compounds, namely Cu2SnSe 3 and Cu3SbSe4, are synthesized, characterized, and optimized for thermoelectric applications. It is found that sample-to-sample variations in hole concentration limits the plausibility of Cu2SnSe3 as a thermoelectric material. Cu3SbSe 4 is found to be a promising material that can achieve thermoelectric performance comparable to state-of-the-art materials when optimized. This work uncovers anomalous thermal conductivity in several Cu-Sb-Se ternary compounds, which is used to develop a set of guidelines relating crystal structure to inherently low lattice thermal conductivity.

  12. DLC coatings for UHMWPE: relationship between bacterial adherence and surface properties.

    Science.gov (United States)

    Del Prado, G; Terriza, A; Ortiz-Pérez, A; Molina-Manso, D; Mahillo, I; Yubero, F; Puértolas, J A; Manrubia-Cobo, M; Gómez Barrena, E; Esteban, J

    2012-10-01

    Development of intrinsically antibacterial surfaces is of key importance in the context of prostheses used in orthopedic surgery. This work presents a thorough study of several plasma-based coatings that may be used with this functionality: diamond-like carbon (DLC), fluorine-doped DLC (F-DLC), and a high-fluorine-content-carbon-fluor polymer (CF(X)). The coatings were obtained by a radio-frequency plasma-assisted deposition on ultra high molecular weight polyethylene (UHMWPE) samples and physicochemical properties of the coated surfaces were correlated with their antibacterial performance against collection and clinical Staphylococcus aureus and Staphylococcus epidermidis strains. The fluorine content and the relative amount of C-C and C-F bonds were controlled by X-ray photoelectron spectroscopy, and hydrophobicity and surface tension by contact angle measurements. Surface roughness was studied by Atomic Force Microscopy. Additional nanoidentation studies were performed for DLC and F-DLC coatings. Unpaired t test and regression linear models evaluated the adherence of S. aureus and S. epidermidis on raw and coated UHMWPE samples. Comparing with UHMWPE, DLC/UHMWPE was the least adherent surface with independence of the bacterial species, finding significant reductions (p ≤ 0.001) for nine staphylococci strains. Bacterial adherence was also significantly reduced in F-DLC/ UHMWPE and CFx/UHMWPE for six strains.

  13. Exact Realization of a Quantum-Dimer Model in Heisenberg Antiferromagnets on a Diamond-Like Decorated Lattice

    Science.gov (United States)

    Hirose, Yuhei; Oguchi, Akihide; Fukumoto, Yoshiyuki

    2016-09-01

    We study Heisenberg antiferromagnets on a diamond-like decorated square lattice perturbed by further neighbor couplings. The second-order effective Hamiltonian is calculated and the resultant Hamiltonian is found to be a square-lattice quantum-dimer model with a finite hopping amplitude and no repulsion, which suggests the stabilization of the plaquette phase. Our recipe for constructing quantum-dimer models can be adopted for other lattices and provides a route for the experimental realization of quantum-dimer models.

  14. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Self-limiting of the thickness of diamond-like films deposited in the laser pyrolysis of liquid aromatic hydrocarbons

    Science.gov (United States)

    Simakin, Aleksandr V.; Lubnin, Evgenii N.; Shafeev, Georgii A.

    2000-03-01

    The process involving the self-regulation of the thickness of a diamond-like film, deposited on the interface between a transparent dielectric substrate (glass, sapphire, quartz) when a liquid aromatic hydrocarbon is heated by the radiation of a copper vapour laser, was observed and investigated. The film thickness reaches 100 nm and ceases to depend on the number of laser pulses, whereas the depth of the ablated region of the substrate, in which the film is deposited, increases monotonically. The self-regulation effect, observed over a wide range of pressures (from 0.08 to 10 bar), is caused both by the heating of the deposited film by the laser radiation to the graphitisation temperature and by its mechanical damage as a consequence of the difference between the coefficients of thermal expansion of the film and the substrate. The latter has been confirmed with the aid of x-ray Auger spectroscopy, the results of which indicate the formation in the liquid of a nanodisperse suspension of carbon particles with the diamond type of bonding.

  15. A novel zinc(ii) metal-organic framework with a diamond-like structure: synthesis, study of thermal robustness and gas adsorption properties.

    Science.gov (United States)

    Almáši, Miroslav; Zeleňák, Vladimír; Zukal, Arnošt; Kuchár, Juraj; Čejka, Jiří

    2016-01-21

    A solvothermal reaction of Zn(ii) salt with methanetetrabenzoic acid (H4MTB) and 1,4,8,11-tetraazacyclotetradecane (cyclam, CYC) created a new microporous metal-organic framework {[Zn2(μ4-MTB)(κ(4)-CYC)2]·2DMF·7H2O}n (DMF = N,N'-dimethylformamide). Single crystal X-ray diffraction showed that the complex exhibits a four-fold interpenetrated diamond-like structure topology with 1D jar-like channels with sizes about 14.1 × 14.1 and 2.4 × 2.4 Å(2). The stability of the framework and activation conditions of the compound have been studied by high-energy powder X-ray diffraction during in situ heating, thermogravimetric analysis coupled with mass spectrometry and infrared spectroscopy performed at different temperatures. The gas adsorption behaviour of {[Zn2(μ4-MTB)(κ(4)-CYC)2]·2DMF·7H2O}n was studied by adsorption of Ar, N2, CO2 and H2. Nitrogen and argon adsorption showed that the activated sample exhibits Brunauer-Emmet-Teller (BET) specific surface areas of 644 m(2) g(-1) (N2) and 562 m(2) g(-1) (Ar). The complex adsorbs carbon dioxide with a maximum storage capacity of 10.5 wt% at 273 K and 101 kPa. The observed hydrogen uptake was 1.27 wt% at 77 K and 800 Torr, which is the highest value reported for the compounds containing a MTB(4-) linker. The adsorption heats of carbon dioxide and hydrogen, calculated according to the Clausius-Clapeyron equation, were in the range 22.8-22.4 kJ mol(-1) for CO2 and 8.9-3.2 kJ mol(-1) for H2, indicating weak interactions of the gases with the framework.

  16. Theoretical investigation of superconductivity in ternary silicide NaAlSi with layered diamond-like structure

    Science.gov (United States)

    Tütüncü, H. M.; Karaca, Ertuǧrul; Srivastava, G. P.

    2016-04-01

    We have investigated the electronic structure, phonon modes and electron-phonon coupling to understand superconductivity in the ternary silicide NaAlSi with a layered diamond-like structure. Our electronic results, using the density functional theory within a generalized gradient approximation, indicate that the density of states at the Fermi level is mainly governed by Si p states. The largest contributions to the electron-phonon coupling parameter involve Si-related vibrations both in the x-y plane as well as along the z-axis in the x-z plane. Our results indicate that this material is an s-p electron superconductor with a medium level electron-phonon coupling parameter of 0.68. Using the Allen-Dynes modification of the McMillan formula we obtain the superconducting critical temperature of 6.98 K, in excellent agreement with experimentally determined value of 7 K.

  17. Combining different modes of high-power ion beam application for creation of metallic and diamond-like coatings

    International Nuclear Information System (INIS)

    Some results of the experiments on thin film deposition using pulsed high-power ion beam (HPIB) are reported. Ti, Nb, Pt, and C films were produced from ablation plasma generated under the action of pulsed HPIB on a surface of ablated materials. We are developing the combined technology that deals with cleaning a substrate surface by HPIB, thin film deposition by HPIB, and the radiation-induced mass transfer of elements of both film and substrate to increase the adhesion. The deposition of the diamond-like titanium carbide has been realized on the basis of the scheme including Ti film deposition. C film deposition, and the ion beam mixing to form TiC carbide. The main parameters of the Ti-substrate transition layers have been determined for different regimes of their creation by Rutherford backscattering (RBS). Ti, Nb, and Pt coatings were deposited on silicon cantilevers used in high-resolution scanning probe microscopes. The analysis of the composition of TiC coatings at a substrate was performed using the Auger electron spectroscopy (AES) method

  18. Design of a 3D photonic band gap cavity in a diamond-like inverse woodpile photonic crystal

    CERN Document Server

    Woldering, Léon A; Vos, Willem L

    2014-01-01

    We theoretically investigate the design of cavities in a three-dimensional (3D) inverse woodpile photonic crystal. This class of cubic diamond-like crystals has a very broad photonic band gap and consists of two perpendicular arrays of pores with a rectangular structure. The point defect that acts as a cavity is centred on the intersection of two intersecting perpendicular pores with a radius that differs from the ones in the bulk of the crystal. We have performed supercell bandstructure calculations with up to $5 \\times 5 \\times 5$ unit cells. We find that up to five isolated and dispersionless bands appear within the 3D photonic band gap. For each isolated band, the electric-field energy is localized in a volume centred on the point defect, hence the point defect acts as a 3D photonic band gap cavity. The mode volume of the cavities resonances is as small as 0.8 $\\lambda^{3}$ (resonance wavelength cubed), indicating a strong confinement of the light. By varying the radius of the defect pores we found that o...

  19. Quantitative Evaluation of Bacteria Adherent and in Biofilm on Single-Wall Carbon Nanotube-Coated Surfaces

    Directory of Open Access Journals (Sweden)

    Fabrizio Pantanella

    2011-01-01

    Full Text Available Biofilm is a common bacterial lifestyle, and it plays a crucial role in human health, causing biofilm-mediated infections. Recently, to counteract biofilm development, new nano-structured biomaterials have been proposed. However, data about the antibacterial properties of nano-structured surfaces are fragmentary and controversial, and, in particular, the susceptibility of nano-structured materials to colonization and biofilm formation by bacterial pathogens has not been yet thoroughly considered. Here, the ability of the pathogenic Streptococcus mutans and Pseudomonas aeruginosa to adhere and form biofilm on surfaces coated with single-wall carbon nanotubes (SWCNTs was analyzed. Our results showed that the surfaces of SWCNTs-coated glass beads (SWCNTs-GBs were colonized at the same extent of uncoated GBs both by S. mutans and P. aeruginosa. In conclusion, our results demonstrate that single wall SWCNTs-coated surfaces are not suitable to counteract bacterial adhesion and biofilm development.

  20. Effect of Magnetic Field on the Deposition of Transparent Diamond-Like Carbon ( DLC ) Films by RF-PCVD

    Institute of Scientific and Technical Information of China (English)

    HOU Hui-jun; ZhU Xia-gao; LIN Song-sheng; YUAN Zhen-hai; DAI Da-huang

    2004-01-01

    In order to deposit transparent and hard DLC films, magnetic field was introduced to enhance the plasma density of radiofrequency plasma chemical vapor deposition (RF-PCVD). In this paper, the configuration and computation of external magnetic field B are introduced. The restriction effect of magnetic field B on the charged particles and the effect of magnetic field B on the primary parameters-nonindependent power Pf and self-bias Uz were also studied. The mechanism of how magnetic field B affects self-bias Uz was analyzed.

  1. Voltage assisted asymmetric nanoscale wear on ultra-smooth diamond like carbon thin films at high sliding speeds

    Science.gov (United States)

    Rajauria, Sukumar; Schreck, Erhard; Marchon, Bruno

    2016-01-01

    The understanding of tribo- and electro-chemical phenomenons on the molecular level at a sliding interface is a field of growing interest. Fundamental chemical and physical insights of sliding surfaces are crucial for understanding wear at an interface, particularly for nano or micro scale devices operating at high sliding speeds. A complete investigation of the electrochemical effects on high sliding speed interfaces requires a precise monitoring of both the associated wear and surface chemical reactions at the interface. Here, we demonstrate that head-disk interface inside a commercial magnetic storage hard disk drive provides a unique system for such studies. The results obtained shows that the voltage assisted electrochemical wear lead to asymmetric wear on either side of sliding interface. PMID:27150446

  2. Influence of flow rate on different properties of diamond-like nanocomposite thin films grown by PECVD

    Directory of Open Access Journals (Sweden)

    T. S. Santra

    2012-06-01

    Full Text Available Diamond-like nanocomposite (DLN thin films were deposited on pyrex glass substrate using different flow rate of haxamethyldisiloxane (HMDSO based liquid precursor with nitrogen gas as a glow discharged decomposition by plasma enhanced chemical vapor deposition (PECVD technique. The significant influence of different precursor flow rates on refractive index and thickness of the DLN films was measured by using spectroscopic filmatrics and DEKTAK profilometer. Optical transparency of the DLN thin films was analyzed by UV-VIS-NIR spectrometer. FTIR spectroscopy, provides the information about shifted bonds like SiC2, Si-C, Si-O, C-C, Si-H, C-H, N-H, and O-H with different precursor flow rate. We have estimated the hardness of the DLN films from Raman spectroscopy using Gaussian deconvolution method and tried to investigate the correlation between hardness, refractive index and thickness of the films with different precursor flow rates. The composition and surface morphology of the DLN films were investigated by X-ray photo electron spectroscopy (XPS and atomic force microscopy (AFM respectively. We have analyzed the hardness by intensity ratio (ID/IG of D and G peaks and correlates with hardness measurement by nanoindentation test where hardness increases from 27.8 μl/min to 80.6μl/min and then decreases with increase of flow rate from 80.6μl/min to 149.5μl/min. Finally, we correlates different parameters of structural, optical and tribological properties like film-thickness, refractive index, light transmission, hardness, surface roughness, modulus of elasticity, contact angle etc. with different precursor flow rates of DLN films.

  3. Rethinking adherence.

    Science.gov (United States)

    Steiner, John F

    2012-10-16

    In 2012, the Centers for Medicare & Medicaid Services (CMS) will introduce measures of adherence to oral hypoglycemic, antihypertensive, and cholesterol-lowering drugs into its Medicare Advantage quality program. To meet these quality goals, delivery systems will need to develop and disseminate strategies to improve adherence. The design of adherence interventions has too often been guided by the mistaken assumptions that adherence is a single behavior that can be predicted from readily available patient characteristics and that individual clinicians alone can improve adherence at the population level.Effective interventions require recognition that adherence is a set of interacting behaviors influenced by individual, social, and environmental forces; adherence interventions must be broadly based, rather than targeted to specific population subgroups; and counseling with a trusted clinician needs to be complemented by outreach interventions and removal of structural and organizational barriers. To achieve the adherence goals set by CMS, front-line clinicians, interdisciplinary teams, organizational leaders, and policymakers will need to coordinate efforts in ways that exemplify the underlying principles of health care reform. PMID:23070491

  4. Dep osition and thermal conductivity of diamond-like carb on film on a silicon substrate%类金刚石薄膜在硅基底上的沉积及其热导率∗

    Institute of Scientific and Technical Information of China (English)

    艾立强; 张相雄; 陈民; 熊大曦

    2016-01-01

    Diamond-Like Carbon (DLC) is thought to be a potential material in solving heat dissipation problems in light emitting diode module packages. It is of vital importance in evaluating the thermal conductivity of DLC film deposited on a silicon substrate. In this paper, the molecular dynamics method is used to simulate the formation of a DLC film by the deposition of carbon atoms on a isilicon substrate. Tersoff potential is adopted to reproduce the structures and densities of silicon, carbon, and SiC. A silicon substrate consisting of 544 atoms is located at the bottom of the simulation domain. The substrate is kept at a temperature of 600 K through a Noose-Hover thermostat. Carbon atoms are injected into the substrate individually every 0.5 ps at an energy of 1 eV. After a 7.5 ns deposition process, a 4 nm amorphous film containing 15000 carbon atoms is formed. Injected carbon atoms and substrate silicon atoms are intermixed at the bottom layer of the deposited film while the rest of the film contains only carbon atoms. The density of the film decreases slightly with the increase of the height of the deposited film and the average density is 2.8 g/cm3. Analysis of the coordination number shows that the sp3 fraction of carbon atoms in the film also decreases with the increase of the height of the deposited film, with a maximum value of 22%. It might be caused by the continuous impacts of the subsequently injected carbon atoms on the previously formed DLC film. The thermal conductivities of the DLC film in the planar and normal directions are calculated by the Green-Kubo method. The thermal conductivity of pure diamond film is also calculated for comparison. The results show that the planar thermal conductivity of the deposited DLC film is approximately half of that of the pure diamond film with the same size. It is higher than the normal thermal conductivity of the deposited film. The thermal conductivities of the DLC film in both planar and normal directions

  5. HIV Medication Adherence

    Science.gov (United States)

    HIV Treatment HIV Medication Adherence (Last updated 3/1/2016; last reviewed 3/1/2016) Key Points Medication adherence means sticking ... exactly as prescribed. Why is adherence to an HIV regimen important? Adherence to an HIV regimen gives ...

  6. Infrared nonlinear optical properties of lithium-containing diamond-like semiconductors Li2ZnGeSe4 and Li2ZnSnSe4.

    Science.gov (United States)

    Zhang, Jian-Han; Clark, Daniel J; Brant, Jacilynn A; Sinagra, Charles W; Kim, Yong Soo; Jang, Joon I; Aitken, Jennifer A

    2015-06-28

    Two new lithium-containing diamond-like semiconductors, Li2ZnGeSe4 and Li2ZnSnSe4, have been prepared by high-temperature, solid-state synthesis. Single crystal X-ray diffraction reveals that both compounds adopt the wurtz-kesterite structure type, crystallizing in the noncentrosymmetric space group Pn. X-ray powder diffraction coupled with Rietveld refinement indicates the high degree of phase purity in which the materials are prepared. Both compounds display optical bandgaps around 1.8 eV, wide optical transparency windows from 0.7 to 25 μm and type-I phase matched second harmonic generation starting at 2500 nm and persisting deeper into the infrared. Using the Kurtz powder method, the second-order nonlinear optical coefficient, χ((2)), was estimated to be 19 and 23 pm V(-1) for Li2ZnGeSe4 and Li2ZnSnSe4, respectively. Using a 1064 nm incident laser beam with a pulse width (τ) of 30 ps both compounds exhibit a laser damage threshold of 0.3 GW cm(-2), which is higher than that of the AgGaSe2 reference material measured under identical conditions. Differential thermal analysis shows that the title compounds are stable up to 684 and 736 °C, respectively. These properties collectively demonstrate that Li2ZnGeSe4 and Li2ZnSnSe4 have great potential for applications in tunable laser systems, especially in the infrared and even up to the terahertz regime. Electronic structure calculations using a plane-wave pseudopotential method within density functional theory provide insight regarding the nature of the bandgap and bonding. PMID:26006322

  7. Performance of diamond-like carbon-protected rubber under cyclic friction. I. Influence of substrate viscoelasticity on the depth evolution

    Science.gov (United States)

    Martinez-Martinez, D.; van der Pal, J. P.; Pei, Y. T.; De Hosson, J. Th. M.

    2011-12-01

    In this paper, the influence of the viscoelastic properties of rubber substrate on the tribological behavior of DLC film-coated alkyl acrylate rubber is studied. The mechanical behavior of the rubber was first characterized by creep experiments using spherical indentations. The results were adjusted using a delayed elasticity model, and a numerical simulation of the indentation of the sliding counterpart ball during the tribotest was carried out. The results show a progressive increase of the contact depth, which is in agreement with the experimental observations.

  8. In-situ reflection-XANES study of ZDDP and MoDTC lubricant films formed on steel and diamond like carbon (DLC) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Morina, Ardian, E-mail: A.Morina@leeds.ac.uk [Institute of Engineering Thermofluids, Surfaces and Interfaces, School of Mechanical Engineering, University of Leeds, Leeds (United Kingdom); Zhao, Hongyuan [Institute of Engineering Thermofluids, Surfaces and Interfaces, School of Mechanical Engineering, University of Leeds, Leeds (United Kingdom); Mosselmans, J. Fred W. [Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2014-04-01

    Highlights: • S, P, Zn and Mo species formed in lubricant films can be characterised in-situ and in-lubro by using the reflection mode XAS technique. • Heating the lubricated steel and DLC samples affects the chemical reaction between the adsorbed species and the surface, resulting in different chemical composition of the ZDDP + MoDTC thermal film formed on steel or DLC. • There is a greater effect of temperature on S species than P species formed on ZDDP thermal films. - Abstract: Chemical characterisation of boundary lubricated interfaces is essential for developing mechanistic models that describe lubricant additive interactions with the surface and their effect on tribological performance. In this study the potential for using the synchrotron-based reflection mode X-ray absorption spectroscopy (XAS) technique for in-situ chemical characterisation of lubricant films has been studied. Thermal films formed from zinc dialkyl dithio phosphate (ZDDP) and molybdenum dialkyl dithio carbamate (MoDTC) lubricant additives have been formed and analysed in-situ using the X-ray absorption near edge structure (XANES) spectroscopy technique. The surface sensitivity of this approach was improved by doing the analysis in reflection mode, enabling analysis of only top layer (up to around 10 nm) of the solid surface. In addition, in-lubro analysis of pre-formed tribofilms from the same additives was done using non-vacuum conditions. The results are discussed in conjunction with XANES and X-ray photoelectron spectroscopy (XPS) analysis of similar additives published in the literature. The results obtained are consistent with the existing ZDDP and MoDTC literature and provide some new insight into intermediate species not reported before. The advantages and disadvantages of the developed XANES methodology for in-situ surface chemical analysis of lubricated conditions are discussed.

  9. The effect of humidity on the tribological behavior of diamond-like carbon (DLC) film coated on WC-Co by physical vapor deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Oezmen, Y.; Tanaka, A. [AIST, Tsukuba (Japan). Mech. Eng. Lab.; Sumiya, T. [Nanotec Co., Kasinoha, 277-0882, Kashiwa (Japan)

    2000-11-01

    DLC films have been coated by PVD on WC-Co substrate with and without Si interface. They have been tested under low ({proportional_to}20%) and high ({proportional_to}80%) humidity conditions by reciprocating friction and wear apparatus. For ascertaining the wear mechanism from the topographies of DLC films, optical and SEM images of wear tracks have been taken. Wear debris particles behave as an abrasive agent, depositing into the film and causing the start of failure. There are multiple wear mechanisms, such as fatigue, abrasion, etc., existing simultaneously in the wear of DLC film in both cases. Wear rate decreases as the total wear way increases. For the case of DLC coating without Si interface there is a good correlation between wear rate and friction coefficient. However, this harmony disappears for DLC/Si coating. A chemically activated process may be assumed as the controlling step in the micro crack propagation during the generation of a wear debris particle. The different tribological behaviors of the DLC coatings under different environmental conditions are explained. (orig.)

  10. In-situ reflection-XANES study of ZDDP and MoDTC lubricant films formed on steel and diamond like carbon (DLC) surfaces

    Science.gov (United States)

    Morina, Ardian; Zhao, Hongyuan; Mosselmans, J. Fred W.

    2014-04-01

    Chemical characterisation of boundary lubricated interfaces is essential for developing mechanistic models that describe lubricant additive interactions with the surface and their effect on tribological performance. In this study the potential for using the synchrotron-based reflection mode X-ray absorption spectroscopy (XAS) technique for in-situ chemical characterisation of lubricant films has been studied. Thermal films formed from zinc dialkyl dithio phosphate (ZDDP) and molybdenum dialkyl dithio carbamate (MoDTC) lubricant additives have been formed and analysed in-situ using the X-ray absorption near edge structure (XANES) spectroscopy technique. The surface sensitivity of this approach was improved by doing the analysis in reflection mode, enabling analysis of only top layer (up to around 10 nm) of the solid surface. In addition, in-lubro analysis of pre-formed tribofilms from the same additives was done using non-vacuum conditions. The results are discussed in conjunction with XANES and X-ray photoelectron spectroscopy (XPS) analysis of similar additives published in the literature. The results obtained are consistent with the existing ZDDP and MoDTC literature and provide some new insight into intermediate species not reported before. The advantages and disadvantages of the developed XANES methodology for in-situ surface chemical analysis of lubricated conditions are discussed.

  11. Coaxial carbon plasma gun deposition of amorphous carbon films

    International Nuclear Information System (INIS)

    A unique plasma gun employing coaxial carbon electrodes was used in an attempt to deposit thin films of amorphous diamond-like carbon. A number of different structural, compositional, and electrical characterization techniques were used to characterize these films. These included scanning electron microscopy, scanning transmission electron microscopy, X ray diffraction and absorption, spectrographic analysis, energy dispersive spectroscopy, and selected area electron diffraction. Optical absorption and electrical resistivity measurements were also performed. The films were determined to be primarily amorphous, with poor adhesion to fused silica substrates. Many inclusions of particulates were found to be present as well. Analysis of these particulates revealed the presence of trace impurities, such as Fe and Cu, which were also found in the graphite electrode material. The electrodes were the source of these impurities. No evidence of diamond-like crystallite structure was found in any of the film samples. Details of the apparatus, experimental procedure, and film characteristics are presented

  12. Coaxial carbon plasma gun deposition of amorphous carbon films

    Science.gov (United States)

    Sater, D. M.; Gulino, D. A.; Rutledge, S. K.

    1984-01-01

    A unique plasma gun employing coaxial carbon electrodes was used in an attempt to deposit thin films of amorphous diamond-like carbon. A number of different structural, compositional, and electrical characterization techniques were used to characterize these films. These included scanning electron microscopy, scanning transmission electron microscopy, X ray diffraction and absorption, spectrographic analysis, energy dispersive spectroscopy, and selected area electron diffraction. Optical absorption and electrical resistivity measurements were also performed. The films were determined to be primarily amorphous, with poor adhesion to fused silica substrates. Many inclusions of particulates were found to be present as well. Analysis of these particulates revealed the presence of trace impurities, such as Fe and Cu, which were also found in the graphite electrode material. The electrodes were the source of these impurities. No evidence of diamond-like crystallite structure was found in any of the film samples. Details of the apparatus, experimental procedure, and film characteristics are presented.

  13. Adherence to antidepressants

    Directory of Open Access Journals (Sweden)

    Abimbola Farinde

    2013-01-01

    Full Text Available While major depression is considered a frequent mental illness there are ongoing reports of high non-adherence to antidepressant medications which places suffers at high risk for relapse, recurrence, or greater impairment,. The World Health Organization (WHO defines adherence as the extent to which a person′s behavior (e.g. taking medications can align with the agreed recommendations of a health care provider. Unfortunately while patient may recognize the importance of adherence to antidepressant medications the majority of patients do not adhere to their prescribed antidepressants. Some of the factors that may contribute to or lead to non-adherence include knowingly or unknowingly missing doses, taking extra doses, delaying administration times, or taking drug holidays. Pharmacists have the unique ability to deter non-adherence through the performance of continuous assessment and monitoring of adherence in this population given these accessibility. Additionally, pharmacists are able to develop therapeutic alliances with patients that can help to increase the likelihood of achieving positive patient outcomes. Antidepressant non-adherence can be viewed as a significant public health concern so it is important for patients to be educated about the importance of adherence, and health care professionals should be aware of factors or patient characteristics that can serve as barriers to non-adherence.

  14. Carbon based prosthetic devices

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T. [Los Alamos National Lab., NM (US); Klawitter, J.J.; Ogilvie, W.; Strzepa, P. [Ascension Orthopedics (US); Cook, S.D. [Tulane Univ., New Orleans, LA (US). School of Medicine

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.

  15. Interfacial electrical properties of ion-beam sputter deposited amorphous carbon on silicon

    Science.gov (United States)

    Khan, A. A.; Woollam, J. A.; Chung, Y.; Banks, B.

    1983-01-01

    Amorphous, 'diamond-like' carbon films have been deposited on Si substrates, using ion-beam sputtering. The interfacial properties are studied using capacitance and conductance measurements. Data are analyzed using existing theories for interfacial electrical properties. The density of electronic states at the interface, along with corresponding time constants are determined.

  16. Synthesis of hydrogen-carbon clathrate material and hydrogen evolution therefrom at moderate temperatures and pressures

    Science.gov (United States)

    Lueking, Angela; Narayanan, Deepa

    2011-03-08

    A process for making a hydrogenated carbon material is provided which includes forming a mixture of a carbon source, particularly a carbonaceous material, and a hydrogen source. The mixture is reacted under reaction conditions such that hydrogen is generated and/or released from the hydrogen source, an amorphous diamond-like carbon is formed, and at least a portion of the generated and/or released hydrogen associates with the amorphous diamond-like carbon, thereby forming a hydrogenated carbon material. A hydrogenated carbon material including a hydrogen carbon clathrate is characterized by evolution of molecular hydrogen at room temperature at atmospheric pressure in particular embodiments of methods and compositions according to the present invention.

  17. Adherence to Pharmacological Treatment for Juvenile Bipolar Disorder

    Science.gov (United States)

    Drotar, Dennis; Greenley, Rachel Neff; Demeter, Christine A.; McNamara, Nora K.; Stansbrey, Robert J.; Calabrese, Joseph R.; Stange, Jonathan; Vijay, Priya; Findling, Robert L.

    2007-01-01

    Objective: The objective of this study was to describe the prevalence and correlates of adherence to divalproex sodium (DVPX) and lithium carbonate (Li) combination treatment during the initial stabilization treatment phase. Method: Adherence to Li/DVPX combination therapy was measured by the presence or absence of minimum serum concentrations of…

  18. Adherence to Sublingual Immunotherapy.

    Science.gov (United States)

    Incorvaia, Cristoforo; Mauro, Marina; Leo, Gualtiero; Ridolo, Erminia

    2016-02-01

    Adherence is a major issue in any medical treatment. Allergen immunotherapy (AIT) is particularly affected by a poor adherence because a flawed application prevents the immunological effects that underlie the clinical outcome of the treatment. Sublingual immunotherapy (SLIT) was introduced in the 1990s, and the early studies suggested that adherence and compliance to such a route of administration was better than the traditional subcutaneous route. However, the recent data from manufacturers revealed that only 13% of patients treated with SLIT reach the recommended 3-year duration. Therefore, improved adherence to SLIT is an unmet need that may be achieved by various approaches. The utility of patient education and accurate monitoring during the treatment was demonstrated by specific studies, while the success of technology-based tools, including online platforms, social media, e-mail, and a short message service by phone, is currently considered to improve the adherence. This goal is of pivotal importance to fulfill the object of SLIT that is to modify the natural history of allergy, ensuring a long-lasting clinical benefit, and a consequent pharmaco-economic advantage, when patients complete at least a 3-year course of treatment. PMID:26758865

  19. Recent development of carbon electrode materials and their bioanalytical and environmental applications.

    Science.gov (United States)

    Zhang, Wei; Zhu, Shuyun; Luque, Rafael; Han, Shuang; Hu, Lianzhe; Xu, Guobao

    2016-02-01

    Carbon materials have been extensively investigated due to their diversity, favorable properties, and active applications including electroanalytical chemistry. This critical review discusses new synthetic methods, novel carbon materials, new properties and electroanalytical applications of carbon materials particularly related to the preparation as well as bioanalytical and environmental applications of highly oriented pyrolytic graphite, graphene, carbon nanotubes, various carbon films (e.g. pyrolyzed carbon films, boron-doped diamond films and diamond-like carbon films) and screen printing carbon electrodes. Future perspectives in the field have also been discussed (366 references).

  20. Wear mechanism of Mo−W doped carbon-based coating during boundary lubricated sliding

    OpenAIRE

    Mandal, Paranjayee; Ehiasarian, Arutiun; Hovsepian, Papken

    2015-01-01

    The high temperature tribological applications of state-of-the-art diamond-like-carbon (DLC) coatings in automotive industry are often compromised due to their poor adhesion strength and low thermal stability. A molybdenum and tungsten doped carbon-based coating (Mo−W−C) is developed in order to overcome these limitations and to enhance tribological performance during boundary lubricated sliding at ambient and elevated temperature. The coating was deposited utilising HIPIMS technology. Mo−W−C...

  1. Medication adherence in the elderly

    OpenAIRE

    Angela Frances Yap, BSc (Pharm) (Hons); Thiru Thirumoorthy, MBBS, FRCP (London), FAMS; Yu Heng Kwan, BSc (Pharm) (Hons)

    2016-01-01

    Medication adherence is a crucial component in the treatment of chronic diseases. In the elderly, clinicians are faced with a unique set of problems associated with adherence that they may not have been adequately trained for. In this paper, we demonstrate the importance of medication adherence in the elderly through a case study. The different factors affecting medication adherence in the elderly are highlighted: patient, medication, health care providers, health care system, and socioeconom...

  2. Plasma distribution prop erties of vacuum ribb on-like catho dic arc plasma fliter and Raman studies of diamond-like carb on films p erpared by it%带状真空电弧磁过滤器等离子体分布特性及制备类金刚石膜研究∗

    Institute of Scientific and Technical Information of China (English)

    李刘合; 刘红涛; 罗辑; 许亿

    2016-01-01

    As is well known, most filtered cathodic vacuum arc deposition technology adopts filters with various geometries to remove macro particles in the last three decades, but almost all of them have a circular cross-section. Compared with the traditional toroidal duct filters, the rectangular graphite cathodic arc source can have a larger area which can be an arc source of a ribbon-like cathodic arc plasma filter, which has a higher coating efficiency due to its larger area arc source and may be more suitable for a larger scale industrial production. Thus, the research on the plasma distribution properties within the vacuum ribbon-like cathodic arc plasma filter is of great significance. In this paper, a rectangular graphite cathodic arc source is used to produce the ribbon-like cathodic arc plasma. Within the filter, a 90◦ curved magnetic duct with a rectangular cross-section is used as the arc filter. The ribbon-like cathodic arc plasma is transmitted from cathode to the deposition area along the magnetic line produced by external coils. A Faraday cup ion energy analyzer and a Langmuir probe are used to characterize the distribution properties of the filtered plasma at 15 places on the exit plane. Ion energies and ion density at these positions are obtained. For the special “retrograde”motion of the cathode spot on the rectangular target surface, the ion energies and ion density data are not stable. In order to obtain representative values, the net results are the average value of 3 measurements. Diamond-like carbon (DLC) films are deposited by the ribbon-like cathodic arc plasma filter at the same exit plane and their structures are characterized by Raman shift. To compare the distinctness of the 15 Raman spectrums, each Raman spectrum of the DLC films is normalized and shown in a figure. Meanwhile, the thicknesses of all the DLC films are measured by step profiler. Results show that the ion energies are of Maxwell distributions at all the 15 places on the exit

  3. [Adherence to psychopharmacological treatment: Psychotherapeutic strategies to enhance adherence].

    Science.gov (United States)

    Lencer, R; Korn, D

    2015-05-01

    Effective psychopharmacological medication with good tolerability represents the cornerstone of treatment for severe mental illness; however, the 1-year adherence rates are only approximately 50%. The term adherence emphasizes the collaborative responsibility of the clinician and the patient for a positive treatment outcome. Reasons for non-adherence are manifold and include patient-specific factors, such as self-stigmatization, lack of social and familial support, cognitive impairment and substance use besides insufficient effectiveness and the occurrence of side effects of the psychotropic drugs. To enhance adherence, both clinician and patient have to fully understand all the reasons for and against adherence to medication before a collaborative decision is made on future long-term treatment. A positive attitude towards medication critically depends on whether patients feel that the medication supports the attainment of the individual goals. PMID:25903501

  4. Investigation of Diamond-like Carbon Films Synthesized by Plasma Gun at an Atmospheric Pressure%大气等离子体枪制备类金刚石薄膜

    Institute of Scientific and Technical Information of China (English)

    汤文杰; 张跃飞; 陈强; 葛袁静

    2006-01-01

    大气下,采用DBD等离子体枪为等离子体聚合装置,以甲烷为单体,氩气为工作气体,在载玻片和单晶硅片上沉积类金刚石薄膜(DLC).考察了基片预处理、内电极形状、进气方式、以及等离子体炬喷口和基材的距离对DLC薄膜沉积的影响.通过傅立叶变换红外光谱(FTIR)分析聚合膜结构并探索可能的沉积机理;表面轮廓仪测定了成膜速率;并对薄膜进行了机械性能测量.

  5. Friction and wear study of diamond-like carbon gradient coatings on Ti6Al4V substrate prepared by plasma source ion implant-ion beam enhanced deposition

    International Nuclear Information System (INIS)

    DLC gradient coatings had been deposited on Ti6Al4V alloy substrate by plasma source ion implantation-ion beam enhanced deposition method and their friction and wear behavior sliding against ultra high molecular weight polyethylene counterpart were investigated. The results showed that DLC gradient coated Ti6Al4V had low friction coefficient, which reduced 24, 14 and 10% compared with non-coated Ti6Al4V alloy under dry sliding, lubrication of bovine serum and 0.9% NaCl solution, respectively. DLC gradient coated Ti6Al4V showed significantly improved wear resistance, the wear rate was about half of non-coated Ti6Al4V alloy. The wear of ultra high molecular weight polyethylene counterpart was also reduced. High adhesion to Ti6Al4V substrate of DLC gradient coatings and surface structure played important roles in improved tribological performance, serious oxidative wear was eliminated when DLC gradient coating was applied to the Ti6Al4V alloy

  6. Investigation on the Nano-Friction Properties of Diamond-like Carbon Films%纳尺度下类金刚石(DLC)薄膜摩擦性能研究

    Institute of Scientific and Technical Information of China (English)

    张艳; 东梅; 李媚; 段早琦

    2015-01-01

    类金刚石薄膜(DLC)作为保护涂层在磁存储系统和微/纳米机电系统(M/NEMS)等方面的应用十分广泛,但其在实际应用中存在着摩擦副的设计问题,本文中采用物理气相沉积(PVD)技术以金属Cr作为过渡层在硅基底上制备类金刚石薄膜,利用原子力显微镜,对类金刚石薄膜的表面特性进行表征,并研究针尖的力学性能对类金刚石薄膜摩擦学性能的影响.结果表明纳尺度下硅针尖和氮化硅针尖测得的摩擦力与法向载荷之间均呈线性关系,这说明针尖材料对类金刚石薄膜的摩擦性能没有影响.Si针尖的SEM图像表明:高载荷下,Si/DLC摩擦副的摩擦系数增加是由于Si针尖的磨损;而类金刚石薄膜的AFM图像表明:Si3N4/DLC摩擦副的摩擦系数增加是由于类金刚石薄膜表面的粗糙峰在高载条件下发生了塑性变形,DMT理论计算验证了我们的实验结果.因此,本研究对于类金刚石薄膜在实际应用中摩擦副的设计具有指导意义.

  7. AFM/FFM Study of Micro/Nano Tribological Properties Diamond-like Carbon Films%类金刚石薄膜摩擦性能AFM/FFM试验

    Institute of Scientific and Technical Information of China (English)

    范真; 丁建宁; 解国新

    2006-01-01

    用摩擦力显微镜(FFM)研究了不同类金刚石(DLC)薄膜的微观摩擦性能.利用化学气相方法沉积制备了DLC薄膜,观察了表面形貌,并测定了其粘附力值,同时,在考虑外加载荷和扫描速度的基础上考察了薄膜的摩擦特性.结果表明:DLC薄膜的表面粗糙度随基底负偏压的增加而减小,而粘附力却相反;DLC薄膜的摩擦系数取决于样品表面粘附力和粗糙度的大小.在扫描速度较小时,由于针尖和样品之间的粘滑作用,摩擦力随探针扫描速度的增加而增大;而当扫描速度较大时,由于DLC薄膜发生相结构转变的缘故,摩擦力却与扫描速度成反比关系.

  8. Experimental Research on Nano-tribological Properties of Diamond-like Carbon Films%类金刚石薄膜纳米摩擦性能的试验研究

    Institute of Scientific and Technical Information of China (English)

    张晶; 范真

    2009-01-01

    利用摩擦力显微镜(FFM),对由等离子体增强化学气相法沉积的类金刚石(DLC)薄膜的纳米摩擦性能进行了试验研究.用原子力显微镜(AFM)观察了DIC薄膜样品的表面形貌,同时测定了其粘附力值.从外加载荷、扫描速度和湿度的角度分析了薄膜的摩擦特性.

  9. Structural morphology of amorphous conducting carbon film

    Indian Academy of Sciences (India)

    P N Vishwakarma; V Prasad; S V Subramanyam; V Ganesan

    2005-10-01

    Amorphous conducting carbon films deposited over quartz substrates were analysed using X-ray diffraction and AFM technique. X-ray diffraction data reveal disorder and roughness in the plane of graphene sheet as compared to that of graphite. This roughness increases with decrease in preparation temperature. The AFM data shows surface roughness of carbon films depending on preparation temperatures. The surface roughness increases with decrease in preparation temperature. Also some nucleating islands were seen on the samples prepared at 900°C, which are not present on the films prepared at 700°C. Detailed analysis of these islands reveals distorted graphitic lattice arrangement. So we believe these islands to be nucleating graphitic. Power spectrum density (PSD) analysis of the carbon surface indicates a transition from the nonlinear growth mode to linear surface-diffusion dominated growth mode resulting in a relatively smoother surface as one moves from low preparation temperature to high preparation temperature. The amorphous carbon films deposited over a rough quartz substrate reveal nucleating diamond like structures. The density of these nucleating diamond like structures was found to be independent of substrate temperature (700–900°C).

  10. Adherence and Readiness to Antiretroviral Treatment

    OpenAIRE

    Södergård, Björn

    2006-01-01

    Antiretroviral therapy places extraordinarily high demands on adherence, since non-adherence affects both individuals and society due to the spread of resistant viral strains. The aims of the thesis were to investigate the prevalence of adherence in Swedish HIV-infected patients, changes in adherence over time, and factors associated with adherence, including patients’ readiness to adhere. Further, to investigate the collaboration between nurses, doctors and pharmacists after the introduction...

  11. Improving adherence to antiretroviral therapy

    Directory of Open Access Journals (Sweden)

    Nischal K

    2005-01-01

    Full Text Available Antiretroviral therapy (ART has transformed HIV infection into a treatable, chronic condition. However, the need to continue treatment for decades rather than years, calls for a long-term perspective of ART. Adherence to the regimen is essential for successful treatment and sustained viral control. Studies have indicated that at least 95% adherence to ART regimens is optimal. It has been demonstrated that a 10% higher level of adherence results in a 21% reduction in disease progression. The various factors affecting success of ART are social aspects like motivation to begin therapy, ability to adhere to therapy, lifestyle pattern, financial support, family support, pros and cons of starting therapy and pharmacological aspects like tolerability of the regimen, availability of the drugs. Also, the regimen′s pill burden, dosing frequency, food requirements, convenience, toxicity and drug interaction profile compared with other regimens are to be considered before starting ART. The lack of trust between clinician and patient, active drug and alcohol use, active mental illness (e.g. depression, lack of patient education and inability of patients to identify their medications, lack of reliable access to primary medical care or medication are considered to be predictors of inadequate adherence. Interventions at various levels, viz. patient level, medication level, healthcare level and community level, boost adherence and overall outcome of ART.

  12. The challenge of patient adherence.

    Science.gov (United States)

    Martin, Leslie R; Williams, Summer L; Haskard, Kelly B; Dimatteo, M Robin

    2005-09-01

    Quality healthcare outcomes depend upon patients' adherence to recommended treatment regimens. Patient nonadherence can be a pervasive threat to health and wellbeing and carry an appreciable economic burden as well. In some disease conditions, more than 40% of patients sustain significant risks by misunderstanding, forgetting, or ignoring healthcare advice. While no single intervention strategy can improve the adherence of all patients, decades of research studies agree that successful attempts to improve patient adherence depend upon a set of key factors. These include realistic assessment of patients' knowledge and understanding of the regimen, clear and effective communication between health professionals and their patients, and the nurturance of trust in the therapeutic relationship. Patients must be given the opportunity to tell the story of their unique illness experiences. Knowing the patient as a person allows the health professional to understand elements that are crucial to the patient's adherence: beliefs, attitudes, subjective norms, cultural context, social supports, and emotional health challenges, particularly depression. Physician-patient partnerships are essential when choosing amongst various therapeutic options to maximize adherence. Mutual collaboration fosters greater patient satisfaction, reduces the risks of nonadherence, and improves patients' healthcare outcomes. PMID:18360559

  13. Adherence with Preventive Medication in Childhood Asthma

    Directory of Open Access Journals (Sweden)

    Scott Burgess

    2011-01-01

    Full Text Available Suboptimal adherence with preventive medication is common and often unrecognised as a cause of poor asthma control. A number of risk factors for nonadherence have emerged from well-conducted studies. Unfortunately, patient report a physician's estimation of adherence and knowledge of these risk factors may not assist in determining whether non-adherence is a significant factor. Electronic monitoring devices are likely to be more frequently used to remind patients to take medication, as a strategy to motivate patients to maintain adherence, and a tool to evaluate adherence in subjects with poor disease control. The aim of this paper is to review non-adherence with preventive medication in childhood asthma, its impact on asthma control, methods of evaluating non-adherence, risk factors for suboptimal adherence, and strategies to enhance adherence.

  14. Carbon The Future Material for Advanced Technology Applications

    CERN Document Server

    Messina, Giacomo

    2006-01-01

    Carbon-based materials and their applications constitute a burgeoning topic of scientific research among scientists and engineers attracted from diverse areas such as applied physics, materials science, biology, mechanics, electronics and engineering. Further development of current materials, advances in their applications, and discovery of new forms of carbon are the themes addressed by the frontier research in these fields. This book covers all the fundamental topics concerned with amorphous and crystalline C-based materials, such as diamond, diamond-like carbon, carbon alloys, carbon nanotubes. The goal is, by coherently progressing from growth - and characterisation techniques to technological applications for each class of material, to fashion the first comprehensive state-of-the-art review of this fast evolving field of research in carbon materials.

  15. Adherence to the Treatment in Psychiatric Patients

    Directory of Open Access Journals (Sweden)

    Mehmet Emin Demirkol

    2015-09-01

    Conclusion: Although medical treatments and drug industry develop day by day, there have been no changes in the treatment adherence ratios in the past years. To generate possible solutions, treatment adherence should be assessed in all clinical interviews and if patient is non-adherent this issue should be handled seriously. [Cukurova Med J 2015; 40(3.000: 555-568

  16. Adherence and health care costs

    Directory of Open Access Journals (Sweden)

    Iuga AO

    2014-02-01

    Full Text Available Aurel O Iuga,1,2 Maura J McGuire3,4 1Johns Hopkins Bloomberg School of Public Health, 2Johns Hopkins University, 3Johns Hopkins Community Physicians, 4Johns Hopkins University School of Medicine, Baltimore, MD, USA Abstract: Medication nonadherence is an important public health consideration, affecting health outcomes and overall health care costs. This review considers the most recent developments in adherence research with a focus on the impact of medication adherence on health care costs in the US health system. We describe the magnitude of the nonadherence problem and related costs, with an extensive discussion of the mechanisms underlying the impact of nonadherence on costs. Specifically, we summarize the impact of nonadherence on health care costs in several chronic diseases, such as diabetes and asthma. A brief analysis of existing research study designs, along with suggestions for future research focus, is provided. Finally, given the ongoing changes in the US health care system, we also address some of the most relevant and current trends in health care, including pharmacist-led medication therapy management and electronic (e-prescribing. Keywords: patient, medication, adherence, compliance, nonadherence, noncompliance, cost

  17. Cryopreservation of adherent neuronal networks.

    Science.gov (United States)

    Ma, Wu; O'Shaughnessy, Thomas; Chang, Eddie

    2006-07-31

    Neuronal networks have been widely used for neurophysiology, drug discovery and toxicity testing. An essential prerequisite for future widespread application of neuronal networks is the development of efficient cryopreservation protocols to facilitate their storage and transportation. Here is the first report on cryopreservation of mammalian adherent neuronal networks. Dissociated spinal cord cells were attached to a poly-d-lysine/laminin surface and allowed to form neuronal networks. Adherent neuronal networks were embedded in a thin film of collagen gel and loaded with trehalose prior to transfer to a freezing medium containing DMSO, FBS and culture medium. This was followed by a slow rate of cooling to -80 degrees C for 24 h and then storage for up to 2 months in liquid nitrogen at -196 degrees C. The three components: DMSO, collagen gel entrapment and trehalose loading combined provided the highest post-thaw viability, relative to individual or two component protocols. The post-thaw cells with this protocol demonstrated similar neuronal and astrocytic markers and morphological structure as those detected in unfrozen cells. Fluorescent dye FM1-43 staining revealed active recycling of synaptic vesicles upon depolarizing stimulation in the post-thaw neuronal networks. These results suggest that a combination of DMSO, collagen gel entrapment and trehalose loading can significantly improve conventional slow-cooling methods in cryopreservation of adherent neuronal networks.

  18. Adherence and quality of care in IBD

    DEFF Research Database (Denmark)

    Bager, Palle; Julsgaard, Mette; Vestergaard, Thea;

    2016-01-01

    different aspects of adherence and to identify predictors of non-adherence, including the quality of care, for outpatients with IBD. MATERIALS AND METHODS: An anonymous electronic questionnaire was used to investigate different aspects of adherence, the quality of care, patient involvement and shared...... decision making among 377 IBD outpatients. RESULTS: Three hundred (80%) filled in the questionnaire. The overall adherence rate was 93%. Young age (< 35 years old) and smoking were significantly associated with non-adherence (prevalence odds ratio (POR) 2.98, 95% CI 1.04-8.52, p < 0.05 and POR 3.88, 95% CI...

  19. RF plasma cleaning of optical surfaces: A study of cleaning rates on different carbon allotropes as a function of RF powers and distances

    CERN Document Server

    Cuxart, M González; Šics, I; Goñi, A R; Fernandez, H Moreno; Carlino, V; Pellegrin, E

    2015-01-01

    An extended study on an advanced method for the cleaning of carbon contaminations on large optical surfaces using a remote inductively coupled low pressure RF plasma source (GV10x downstream asher) is reported in this work. Technical as well as scientific features of this scaled up cleaning process are analyzed, such as the cleaning efficiency for different carbon allotropes (amorphous and diamond-like carbon) as a function of feedstock gas composition, RF power (ranging from 30 to 300W), and source-object distances (415 to 840 mm). The underlying physical phenomena for these functional dependences are discussed.

  20. Preparation of hollow spherical carbon nanocages

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, C.-K.; Kang, H. Y.; Hong, C.-I; Huang, C.-H.; Chang, F.-C.; Wang, H. Paul, E-mail: wanghp@mail.ncku.edu.tw [National Cheng Kung University, Department of Environmental Engineering, Taiwan (China)

    2012-12-15

    This study presents a new and simple method for the synthesis of hollow carbon spheres possessing nanocage sizes of 7.1, 14, and 20 nm in diameter. The core-shell (i.e., Cu-C) nanoparticles prepared by carbonization of the Cu{sup 2+}-cyclodextrin (CD) complexes at 573 K for 2 h was etched with HCl (6N) to yield the hollow carbon spheres. The carbon-shell of the hollow carbon nanospheres, which consisted of mainly diamond-like and graphite carbons, is not perturbed during etching. In addition to the nanocages, the hollow carbon nanospheres also possess micropores with an opening of 0.45 nm, allowing small molecules to diffuse in and out through the carbon-shell. Many elements (such as Zn{sup 2+} or Cu{sup 2+}) can therefore be filled into the nanocages of the hollow carbon nanospheres. With these unique properties, for instance, designable active species such as Cu and ZnO encapsulated in the carbon-shell can act as Cu-ZnO-C yolk-shell nanoreactors which are found very effective in the catalytic decomposition of methanol.

  1. Plasmodium vivax adherence to placental glycosaminoglycans.

    Directory of Open Access Journals (Sweden)

    Kesinee Chotivanich

    Full Text Available BACKGROUND: Plasmodium vivax infections seldom kill directly but do cause indirect mortality by reducing birth weight and causing abortion. Cytoadherence and sequestration in the microvasculature are central to the pathogenesis of severe Plasmodium falciparum malaria, but the contribution of cytoadherence to pathology in other human malarias is less clear. METHODOLOGY: The adherence properties of P. vivax infected red blood cells (PvIRBC were evaluated under static and flow conditions. PRINCIPAL FINDINGS: P. vivax isolates from 33 patients were studied. None adhered to immobilized CD36, ICAM-1, or thrombospondin, putative ligands for P. falciparum vascular cytoadherence, or umbilical vein endothelial cells, but all adhered to immobilized chondroitin sulphate A (CSA and hyaluronic acid (HA, the receptors for adhesion of P. falciparum in the placenta. PvIRBC also adhered to fresh placental cells (N = 5. Pre-incubation with chondroitinase prevented PvIRBC adherence to CSA, and reduced binding to HA, whereas preincubation with hyaluronidase prevented adherence to HA, but did not reduce binding to CSA significantly. Pre-incubation of PvIRBC with soluble CSA and HA reduced binding to the immobilized receptors and prevented placental binding. PvIRBC adhesion was prevented by pre-incubation with trypsin, inhibited by heparin, and reduced by EGTA. Under laminar flow conditions the mean (SD shear stress reducing maximum attachment by 50% was 0.06 (0.02 Pa but, having adhered, the PvIRBC could then resist detachment by stresses up to 5 Pa. At 37 °C adherence began approximately 16 hours after red cell invasion with maximal adherence at 30 hours. At 39 °C adherence began earlier and peaked at 24 hours. SIGNIFICANCE: Adherence of P. vivax-infected erythrocytes to glycosaminoglycans may contribute to the pathogenesis of vivax malaria and lead to intrauterine growth retardation.

  2. Intent-to-adhere and adherence to malaria prevention recommendations in two travel clinics.

    Science.gov (United States)

    Goldstein, Irit; Grefat, Rami; Ephros, Moshe; Rishpon, Shmuel

    2015-01-01

    Malaria infects 30,000 travelers annually worldwide. At greatest risk are those who travel for long duration. Prevention of malaria includes chemoprophylaxis. This prospective study on 121 travelers who visited two travel clinics shows that adherence to prophylactic treatment was low, especially in long duration trips, and that adherence rate could be predicted by the much more available intent-to-adhere rate.

  3. Nanosized Carbon Dots from Organic Matter and Biomass

    Institute of Scientific and Technical Information of China (English)

    LI Yuanyuan; CHEN Tong; MA Yulong

    2016-01-01

    Carbon nanoparticles (C-dots) were prepared by relfuxing the combustion soots of candles and corn stalk in nitric acid. The synthesized C-dots were characterized. The results showed a sharp increase in oxygen content and a sharp decrease in carbon content after oxidation. The C-dots had -OH and -CO2H groups introduced which made them hydrophilic. However, their difference was also obvious. The C-dots from candle soot had a 10-45 nm broad particle size distribution, and those from corn stalk soot had a 6-18 nm relatively small and narrow size distribution. The C-dots were mainly ofsp2 andsp3 carbon structure different from the C-dots of diamond-like structure from candle soot. Interestingly, two kinds of C-dots all exhibited unique photoluminescent properties. The obtained C-dots have potential applications in a broad range of areas.

  4. Asthma and Adherence to Inhaled Corticosteroids

    DEFF Research Database (Denmark)

    Bårnes, Camilla Boslev; Ulrik, Charlotte Suppli

    2015-01-01

    Inhaled corticosteroids (ICS) are the cornerstone of maintenance asthma therapy. However, in spite of this, adherence to ICS remains low. The aim of this systematic literature review was to provide an overview of the current knowledge of adherence to ICS, effects of poor adherence, and means...... was found to be between 22 and 63%, with improvement up to and after an exacerbation. Poor adherence was associated with youth, being African-American, having mild asthma, ... prescribed fixed-combination therapy (ICS and long-acting β2 agonists). Good adherence was associated with higher FEV1, a lower percentage of eosinophils in sputum, reduction in hospitalizations, less use of oral corticosteroids, and lower mortality rate. Overall, 24% of exacerbations and 60% of asthma...

  5. Adherence to vitamin supplementation following adolescent bariatric surgery

    OpenAIRE

    Modi, Avani C.; Zeller, Meg H.; Xanthakos, Stavra A.; Jenkins, Todd M.; Inge, Thomas H.

    2013-01-01

    Adolescents with extreme obesity, who have undergone bariatric surgery, must adhere to many lifestyle and nutritional recommendations, including multivitamin therapy. Little is know about multivitamin adherence following adolescent bariatric surgery. The present study aims to document self-reported and electronically-monitored adherence to multivitamins, determine convergence between self-report and electronic monitoring adherence for multivitamins, and identify barriers to multivitamin adher...

  6. Silicon Carbide Derived Carbons: Experiments and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Kertesz, Miklos [Georgetown University, Washington DC 20057

    2011-02-28

    The main results of the computational modeling was: 1. Development of a new genealogical algorithm to generate vacancy clusters in diamond starting from monovacancies combined with energy criteria based on TBDFT energetics. The method revealed that for smaller vacancy clusters the energetically optimal shapes are compact but for larger sizes they tend to show graphitized regions. In fact smaller clusters of the size as small as 12 already show signatures of this graphitization. The modeling gives firm basis for the slit-pore modeling of porous carbon materials and explains some of their properties. 2. We discovered small vacancy clusters and their physical characteristics that can be used to spectroscopically identify them. 3. We found low barrier pathways for vacancy migration in diamond-like materials by obtaining for the first time optimized reaction pathways.

  7. Adherence to Antihypertensive Medications in Iranian Patients.

    Science.gov (United States)

    Behnood-Rod, Azin; Rabbanifar, Omid; Pourzargar, Pirouz; Rai, Alireza; Saadat, Zahra; Saadat, Habibollah; Moharamzad, Yashar; Morisky, Donald E

    2016-01-01

    Introduction. Appropriate adherence to medication is still a challenging issue for hypertensive patients. We determined adherence to antihypertensive(s) and its associated factors among 280 Iranian patients. Methods. They were recruited consecutively from private and university health centers and pharmacies in four cities. The validated Persian version of the 8-item Morisky Medication Adherence Scale (MMAS-8) was administered to measure adherence. Results. Mean (±SD) overall MMAS-8 score was 5.75 (±1.88). About half of the sample (139 cases, 49.6%) showed low adherence (MMAS-8 score emergency services due to hypertensive crisis (B = -0.79, P = 0.001), and getting medication directly from drugstore without refill prescription in hand (B = -0.51, P = 0.04) were factors recognized to have statistically significant association with the MMAS-8 score. Conclusion. Antihypertensive adherence was unsatisfactory. We suggest that health care providers pay special attention and make use of the aforementioned findings in their routine visits of hypertensive patients to recognize those who are vulnerable to poor adherence. PMID:27069676

  8. Adherence to Antihypertensive Medications in Iranian Patients

    Directory of Open Access Journals (Sweden)

    Azin Behnood-Rod

    2016-01-01

    Full Text Available Introduction. Appropriate adherence to medication is still a challenging issue for hypertensive patients. We determined adherence to antihypertensive(s and its associated factors among 280 Iranian patients. Methods. They were recruited consecutively from private and university health centers and pharmacies in four cities. The validated Persian version of the 8-item Morisky Medication Adherence Scale (MMAS-8 was administered to measure adherence. Results. Mean (±SD overall MMAS-8 score was 5.75 (±1.88. About half of the sample (139 cases, 49.6% showed low adherence (MMAS-8 score < 6. There was a negative linear association between the MMAS-8 score and systolic BP (r=-0.231, P<0.001 as well as diastolic BP (r=-0.280, P<0.001. In linear regression model, overweight/obesity (B=-0.52, P=0.02, previous history of admission to emergency services due to hypertensive crisis (B=-0.79, P=0.001, and getting medication directly from drugstore without refill prescription in hand (B=-0.51, P=0.04 were factors recognized to have statistically significant association with the MMAS-8 score. Conclusion. Antihypertensive adherence was unsatisfactory. We suggest that health care providers pay special attention and make use of the aforementioned findings in their routine visits of hypertensive patients to recognize those who are vulnerable to poor adherence.

  9. Integrated Carbon Nanostructures for Detection of Neurotransmitters.

    Science.gov (United States)

    Sainio, Sami; Palomäki, Tommi; Tujunen, Noora; Protopopova, Vera; Koehne, Jessica; Kordas, Krisztian; Koskinen, Jari; Meyyappan, M; Laurila, Tomi

    2015-10-01

    Carbon-based materials, such as diamond-like carbon (DLC), carbon nanofibers (CNFs), and carbon nanotubes (CNTs), are inherently interesting for neurotransmitter detection due to their good biocompatibility, low cost and relatively simple synthesis. In this paper, we report on new carbon-hybrid materials, where either CNTs or CNFs are directly grown on top of tetrahedral amorphous carbon (ta-C). We show that these hybrid materials have electrochemical properties that not only combine the best characteristics of the individual "building blocks" but their synergy makes the electrode performance superior compared to conventional carbon based electrodes. By combining ta-C with CNTs, we were able to realize electrode materials that show wide and stable water window, almost reversible electron transfer properties and high sensitivity and selectivity for detecting dopamine in the presence of ascorbic acid. Furthermore, the sensitivity of ta-C + CNF hybrids towards dopamine as well as glutamate has been found excellent paving the road for actual in vivo measurements. The wide and stable water window of these sensors enables detection of other neurotransmitters besides DA as well as capability of withstanding higher potentials without suffering from oxygen and hydrogen evolution. PMID:26093378

  10. Structure and properties of diamond and diamond-like films

    Energy Technology Data Exchange (ETDEWEB)

    Clausing, R.E. [Oak Ridge National Lab., TN (United States)

    1993-01-01

    This section is broken into four parts: (1) introduction, (2) natural IIa diamond, (3) importance of structure and composition, and (4) control of structure and properties. Conclusions of this discussion are that properties of chemical vapor deposited diamond films can compare favorably with natural diamond, that properties are anisotropic and are a strong function of structure and crystal perfection, that crystal perfection and morphology are functions of growth conditions and can be controlled, and that the manipulation of texture and thereby surface morphology and internal crystal perfection is an important step in optimizing chemically deposited diamond films for applications.

  11. Surface bioactivity of plasma implanted silicon and amorphous carbon

    Institute of Scientific and Technical Information of China (English)

    Paul K CHU

    2004-01-01

    Plasma immersion ion implantation and deposition (PⅢ&D) has been shown to be an effective technique to enhance the surface bioactivity of materials. In this paper, recent progress made in our laboratory on plasma surface modification single-crystal silicon and amorphous carbon is reviewed. Silicon is the most important material in the integrated circuit industry but its surface biocompatibility has not been investigated in details. We have recently performed hydrogen PⅢ into silicon and observed the biomimetic growth of apatite on its surface in simulated body fluid. Diamond-like carbon (DLC) is widely used in the industry due to its excellent mechanical properties and chemical inertness. The use of this material in biomedical engineering has also attracted much attention. It has been observed in our laboratory that doping DLC with nitrogen by means of PⅢ can improve the surface blood compatibility. The properties as well as in vitro biological test results will be discussed in this article.

  12. COMMITTED TO CARBON REDUCTION

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Chinese efforts to lower carbon emissions through environmentally friendly means begin gaining momentum Efforts to curb carbon emissions continue to take shape as China adheres to its pledge for a brighter, greener future. More importantly, as environmental measures take hold and develop

  13. On World Religion Adherence Distribution Evolution

    OpenAIRE

    Ausloos, M.; Petroni, F.

    2008-01-01

    Religious adherence can be considered as a degree of freedom, in a statistical physics sense, for a human agent belonging to a population. The distribution, performance and life time of religions can thus be studied having in mind heterogeneous interacting agent modeling in mind. We present a comprehensive analysis of 58 so called religion (to be better defined in the main text) evolutions, as measured through their number of adherents between 1900 and 2000, - data taken from the World Christ...

  14. Adherence of Staphylococcus epidermidis to intraocular lenses.

    OpenAIRE

    Griffiths, P G; Elliot, T. S.; McTaggart, L

    1989-01-01

    We have demonstrated, with an in vitro model, that Staphylococcus epidermidis is able to colonise intraocular lenses. Adherent organisms were quantitated by light microscopy, scanning electron microscopy, and viable counting. Bacterial adherence was associated with production of a polysaccharide glycocalyx. Organisms which were attached to the lenses were resistant to apparently bactericidal concentrations of antibiotics, as determined by conventional testing. We speculate on the role of colo...

  15. Understanding how adherence goals promote adherence behaviours: a repeated measure observational study with HIV seropositive patients

    OpenAIRE

    Jones Gareth; Hawkins Kim; Mullin Rebecca; Nepusz Tamás; Naughton Declan P; Sheeran Paschal; Petróczi Andrea

    2012-01-01

    Abstract Background The extent to which patients follow treatments as prescribed is pivotal to treatment success. An exceptionally high level (> 95%) of HIV medication adherence is required to suppress viral replication and protect the immune system and a similarly high level (> 80%) of adherence has also been suggested in order to benefit from prescribed exercise programmes. However, in clinical practice, adherence to both often falls below the desirable level. This project aims to investiga...

  16. Microbicide clinical trial adherence: insights for introduction

    Directory of Open Access Journals (Sweden)

    Cynthia Woodsong

    2013-04-01

    Full Text Available After two decades of microbicide clinical trials it remains uncertain if vaginally- delivered products will be clearly shown to reduce the risk of HIV infection in women and girls. Furthermore, a microbicide product with demonstrated clinical efficacy must be used correctly and consistently if it is to prevent infection. Information on adherence that can be gleaned from microbicide trials is relevant for future microbicide safety and efficacy trials, pre-licensure implementation trials, Phase IV post-marketing research, and microbicide introduction and delivery. Drawing primarily from data and experience that has emerged from the large-scale microbicide efficacy trials completed to-date, the paper identifies six broad areas of adherence lessons learned: (1 Adherence measurement in clinical trials, (2 Comprehension of use instructions/Instructions for use, (3 Unknown efficacy and its effect on adherence/Messages regarding effectiveness, (4 Partner influence on use, (5 Retention and continuation and (6 Generalizability of trial participants' adherence behavior. Each is discussed, with examples provided from microbicide trials. For each of these adherence topics, recommendations are provided for using trial findings to prepare for future microbicide safety and efficacy trials, Phase IV post-marketing research, and microbicide introduction and delivery programs.

  17. Microbicide clinical trial adherence: insights for introduction.

    Science.gov (United States)

    Woodsong, Cynthia; MacQueen, Kathleen; Amico, K Rivet; Friedland, Barbara; Gafos, Mitzy; Mansoor, Leila; Tolley, Elizabether; McCormack, Sheena

    2013-01-01

    After two decades of microbicide clinical trials it remains uncertain if vaginally- delivered products will be clearly shown to reduce the risk of HIV infection in women and girls. Furthermore, a microbicide product with demonstrated clinical efficacy must be used correctly and consistently if it is to prevent infection. Information on adherence that can be gleaned from microbicide trials is relevant for future microbicide safety and efficacy trials, pre-licensure implementation trials, Phase IV post-marketing research, and microbicide introduction and delivery. Drawing primarily from data and experience that has emerged from the large-scale microbicide efficacy trials completed to-date, the paper identifies six broad areas of adherence lessons learned: (1) Adherence measurement in clinical trials, (2) Comprehension of use instructions/Instructions for use, (3) Unknown efficacy and its effect on adherence/Messages regarding effectiveness, (4) Partner influence on use, (5) Retention and continuation and (6) Generalizability of trial participants' adherence behavior. Each is discussed, with examples provided from microbicide trials. For each of these adherence topics, recommendations are provided for using trial findings to prepare for future microbicide safety and efficacy trials, Phase IV post-marketing research, and microbicide introduction and delivery programs. PMID:23561044

  18. Assessing adherence factors in patients under topical treatment: development of the Topical Therapy Adherence Questionnaire (TTAQ).

    Science.gov (United States)

    Zschocke, Ina; Mrowietz, Ulrich; Lotzin, Annett; Karakasili, Eleni; Reich, Kristian

    2014-04-01

    Medication adherence rates strongly depend on favorable disease outcomes. It is known that medication adherence rates are lower for topical treatment than for systemic treatment. However, to date no validated instrument for the assessment of adherence factors in topical treatment is available. The aim of this study was to develop a new questionnaire to assess adherence risk factors in topical treatment. The development of the Topical Therapy Adherence Questionnaire (TTAQ) and Patient Preference Questionnaire (PPQ) was based on a systematic literature review, and qualitative patient focus interviews and expert focus groups' input. The psychometric properties and comprehensibility of the TTAQ and PPQ were assessed in a feasibility study with 59 psoriasis patients. Our first preliminary results indicate that the TTAQ and PPQ are psychometrically sound and reliable measures for the assessment of factors influencing topical treatment adherence. The questionnaires are currently being further developed and various parameters (e.g., time point of assessment) are currently being tested in an exploratory pilot study with ca. 2,000 psoriasis patients receiving topical treatment in a European clinical trial. The use of the final versions of TTAQ and PPQ in clinical practice may facilitate the early identification of specific non-adherence factors in patients under topical treatment, which could enable designing and applying adherence-enhancing interventions according to the patient's individual needs.

  19. Improving medication adherence in patients with hypertension

    DEFF Research Database (Denmark)

    Hedegaard, Ulla; Kjeldsen, Lene Juel; Pottegård, Anton;

    2015-01-01

    BACKGROUND: and Purpose: In patients with hypertension, medication adherence is often suboptimal, thereby increasing the risk of ischemic heart disease and stroke. In a randomized trial, we investigated the effectiveness of a multifaceted pharmacist intervention in a hospital setting to improve...... medication adherence in hypertensive patients. Motivational interviewing was a key element of the intervention. METHODS: Patients (N=532) were recruited from 3 hospital outpatient clinics and randomized to usual care or a 6-month pharmacist intervention comprising collaborative care, medication review......, tailored adherence counselling including motivational interviewing and telephone follow-ups. The primary outcome was composite medication possession ratio (MPR) to antihypertensive and lipid-lowering agents, at one-year follow-up, assessed by analyzing pharmacy records. Secondary outcomes at 12 months...

  20. Intense heavy ion beam-induced temperature effects in carbon-based stripper foils

    International Nuclear Information System (INIS)

    At the future FAIR facility, reliably working solid carbon stripper foils are desired for providing intermediate charge states to SIS18. With the expected high beam intensities, the foils experience enhanced degradation and limited lifetime due to severe radiation damage, stress waves, and thermal effects. This work presents systematic measurements of the temperature of different carbon-based stripper foils (amorphous, diamond-like, and carbon-nanotube based) exposed to 4.8 MeV/u U, Bi, and Au beams of different pulse intensities. Thermal and spectroscopic analyses were performed by means of infrared thermography and Fourier transform infrared spectroscopy. The resulting temperature depends on the foil thickness and strongly increases with increasing pulse intensity and repetition rate. (author)

  1. In situ electron spectroscopic identification of carbon species deposited by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Samano, E.C.; Gamietea, A.; Cota, L. [IFUNAM, Ensenada (Mexico). Lab. de Ensenada; Soto, G. [IFUNAM, Ensenada (Mexico). Lab. de Ensenada]|[Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (Mexico). Programa de Posgrado en Fisica de Materiales

    1997-05-01

    Thin carbon films were grown on Si (111) substrates by ablating a graphite target utilizing an excimer pulsed laser in a UHV Riber {copyright} LDM-32 system. Two kinds of films were produced, a highly oriented pyrolytic graphite (HOPG) type and a diamond-like carbon (DLC) type. A relationship of the films microstructure with laser power density and substrate conditions was observed. The HOPG films were homogeneous but the DLC films were heterogeneous, as shown by micrographs. The thin films are monitored and analyzed in situ during the first stages of the deposition process. The monitoring was done by RHEED and the characterization by several surface spectroscopic techniques, AES, XPS and EELS. The formation of a SiC interface was observed for both films due to the reaction of the first carbon species with the substrate surface.

  2. Impact of Adherence Counseling Dose on Antiretroviral Adherence and HIV Viral Load among HIV-Infected Methadone Maintained Drug Users

    OpenAIRE

    Cooperman, Nina A.; Heo, Moonseong; Berg, Karina M.; Li, Xuan; Litwin, Alain H.; Nahvi, Shadi; Arnsten, Julia H.

    2012-01-01

    Adherence counseling can improve antiretroviral adherence and related health outcomes in HIV-infected individuals. However, little is known about how much counseling is necessary to achieve clinically significant effects. We investigated antiretroviral adherence and HIV viral load relative to the number of hours of adherence counseling received by 60 HIV-infected drug users participating in a trial of directly observed antiretroviral therapy delivered in methadone clinics. Our adherence couns...

  3. [Adherence to statins: updates and practical proposals].

    Science.gov (United States)

    Bauwens, Marine; Schneider, Marie-paule; Nanchen, David

    2016-03-01

    Statins are an established treatment for dyslipidemia, because they were shown to decrease the cardiovascular risk by 25%. However, one third of patients using statins don't take them regularly. Statin intolerance is an important risk factor for nonadherence, but health literacy and lack of education regarding the cardiovascular benefits are also important triggers for poor adherence to statins. A better communication between the caregiver and his patient, by taking patient's perspectives into account could help find effective solutions. This article reviews the issue of statins adherence and suggests solutions to improve it. PMID:27089601

  4. Adherence to physiotherapy clinical guideline acute ankle injury and determinants of adherence: a cohort study

    Directory of Open Access Journals (Sweden)

    van Beers Hans

    2007-05-01

    Full Text Available Abstract Background Clinical guidelines are considered important instruments to improve quality in health care. In physiotherapy, insight in adherence to guidelines is limited. Knowledge of adherence is important to identify barriers and to enhance implementation. Purpose of this study is to investigate the ability to adherence to recommendations of the guideline Acute ankle injury, and to identify patient characteristics that determine adherence to the guideline. Methods Twenty-two physiotherapists collected data of 174 patients in a prospective cohort study, in which the course of treatment was systematically registered. Indicators were used to investigate adherence to recommendations. Patient characteristics were used to identify prognostic factors that may determine adherence to the guideline. Correlation between patient characteristics and adherence to outcome-indicators (treatment sessions, functioning of patient, accomplished goals was calculated using univariate logistic regression. To calculate explained variance of combined patient characteristics, multivariate analysis was performed. Results Adherence to individual recommendations varied from 71% to 100%. In 99 patients (57% the physiotherapists showed adherence to all indicators. Adherence to preset maximum of six treatment sessions for patients with severe ankle injury was 81% (132 patients. The odds to receive more than six sessions were statistically significant for three patient characteristics: females (OR:3.89; 95%CI: 1.41–10.72, recurrent sprain (OR: 6.90; 95%CI: 2.34 – 20.37, co-morbidity (OR: 25.92; 95% CI: 6.79 – 98.93. All factors together explained 40% of the variance. Inclusion of physiotherapist characteristics in the regression model showed that work-experience reduced the odds to receive more than six sessions (OR: 0.2; 95%CI: 0.06 – 0.77, and increased explained variance to 45%. Conclusion Adherence to the clinical guideline Acute ankle sprain showed that the

  5. Psoriasis: improving adherence to topical therapy.

    NARCIS (Netherlands)

    Feldman, S.R.; Horn, E.J.; Balkrishnan, R.; Basra, M.K.; Finlay, A.Y.; McCoy, D.; Menter, A.; Kerkhof, P.C.M. van de

    2008-01-01

    Topical therapy has an important role in psoriasis treatment. It is efficacious and has a favorable safety profile as demonstrated in clinical trials. However, poor treatment outcomes from topical therapy regimens likely result from poor adherence and ineffective use of the medication. The Internati

  6. Introducing the Adherence Strategy Engineering Framework (ASEF)

    DEFF Research Database (Denmark)

    Wagner, Stefan Rahr; Toftegaard, Thomas Skjødeberg; Bertelsen, Olav W.

    2013-01-01

    . Methods: Key concepts related to self-care and adherence were defined, discussed, and implemented as part of the ASEF framework. ASEF was applied to seven self-care case studies, and the perceived usefulness and feasibility of ASEF was evaluated in a questionnaire study by the case study participants...

  7. Barriers to adherence in cystic fibrosis

    DEFF Research Database (Denmark)

    Bregnballe, Vibeke; Schiøtz, Peter Oluf

    2012-01-01

    Danish patients with cystic fibrosis aged 14 to 25 years and their parents. Conclusions: The present study showed that the majority of adolescents with CF and their parents experienced barriers to treatment adherence. Patients and parents agreed that the three most common barriers encountered lack...

  8. DRUG COMPLIANCE AND ADHERENCE TO TREATMENT

    Directory of Open Access Journals (Sweden)

    Manmohan

    2012-09-01

    Full Text Available ABSTRACT: BACKGROUND: In spite of any number of medicines will not be of use unless patient takes’ them. After diagnosing the disease, the next most i mportant step is to follow the instructions of physician in terms of treatment. The doctor’s respons ibility does not end with writing prescription, assuming patient will adhere to it. He/ she should cross check the behavior of patient for drug compliance and see that patient follo ws it and get the benefit. Non compliance is the main barrier for the effective delivery of the medical care. This will have greater implications on the economic burde n on the country in terms of frequent hospitalization, use of expensive medicines in case o f relapse due to non adherence.Though the terms compliance and adherence are used synonymously , they differ in the delivery of quality of the medicare as the former implicates the passive fol lowing of the physician instruction, while in the later, patient actively participates in the dev elopment of the treatment plan, which will improves outcome of the treatment. Adherence is the preferred term over compliance by WHO.

  9. Adherence to Exercise and Physical Activity: Preface.

    Science.gov (United States)

    Morgan, William P.; Dishman, Rod K.

    2001-01-01

    Introduces a collection of papers on adherence to exercise programs and physical activity from the 2000 American Academy of Kinesiology and Physical Education conference, which included research on middle school boys and girls, college men and women, and men and women in the later years, as well as on the more traditional subject of middle aged…

  10. Understanding adherence to web-based interventions

    NARCIS (Netherlands)

    Kelders, S.M.

    2012-01-01

    Although eHealth technologies and especially web-based interventions for the promotion of health and health related behavior have been shown to be effective, the impact is hindered by non-adherence: while many eHealth interventions reach a large group of participants, not all of these participants c

  11. Primary non-adherence to prescribed medication in general practice

    DEFF Research Database (Denmark)

    Linnet, Kristján; Halldórsson, Matthías; Thengilsdóttir, Gudrún;

    2013-01-01

    Primary non-adherence refers to the patient not redeeming a prescribed medication at some point during drug therapy. Research has mainly focused on secondary non-adherence. Prior to this study, the overall rate of primary non-adherence in general practice in Iceland was not known.......Primary non-adherence refers to the patient not redeeming a prescribed medication at some point during drug therapy. Research has mainly focused on secondary non-adherence. Prior to this study, the overall rate of primary non-adherence in general practice in Iceland was not known....

  12. Bacterial adherence to anodized titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Peremarch, C Perez-Jorge; Tanoira, R Perez; Arenas, M A; Matykina, E; Conde, A; De Damborenea, J J; Gomez Barrena, E; Esteban, J, E-mail: cperemarch@fjd.es

    2010-11-01

    The aim of this study was to evaluate Staphylococcus sp adhesion to modified surfaces of anodized titanium alloy (Ti-6Al-4V). Surface modification involved generation of fluoride-containing titanium oxide nanotube films. Specimens of Ti-6Al-4V alloy 6-4 ELI-grade 23- meets the requirements of ASTM F136 2002A (AMS 2631B class A1) were anodized in a mixture of sulphuric/hydrofluoric acid at 20 V for 5 and 60 min to form a 100 nm-thick porous film of 20 nm pore diameter and 230 nm-thick nanotube films of 100 nm in diameter. The amount of fluorine in the oxide films was of 6% and of 4%, respectively. Collection strains and six clinical strains each of Staphylococcus aureus and Staphylococcus epidermidis were studied. The adherence study was performed using a previously published protocol by Kinnari et al. The experiments were performed in triplicates. As a result, lower adherence was detected for collection strains in modified materials than in unmodified controls. Differences between clinical strains were detected for both species (p<0.0001, Kruskal-Wallis test), although global data showed similar results to that of collection strains (p<0.0001, Kruskal-Wallis test). Adherence of bacteria to modified surfaces was decreased for both species. The results also reflect a difference in the adherence between S. aureus and S. epidermidis to the modified material. As a conclusion, not only we were able to confirm the decrease of adherence in the modified surface, but also the need to test multiple clinical strains to obtain more realistic microbiological results due to intraspecies differences.

  13. Synthesis and characterization of carbon-coated cobalt ferrite nanoparticles

    Science.gov (United States)

    Bakhshi, Hamed; Shokuhfar, Ali; Vahdati, Nima

    2016-09-01

    Cobalt ferrite nanoparticles (CFNPs) were prepared via a reverse micelle method. The CFNPs were subsequently coated with carbon shells by means of thermal chemical vapor deposition (TCVD). In this process, acetylene gas (C2H2) was used as a carbon source and the coating was carried out for 1, 2, or 3 h at 750°C. The Ar/C2H2 ratio was 10:1. Heating during the TCVD process resulted in a NP core size that approached 30 nm; the thickness of the shell was less than 10 nm. The composition, structure, and morphology of the fabricated composites were characterized using X-ray diffraction, simultaneous thermal analysis, transmission electron microscopy, high-resolution transmission electron microscopy, and selected-area diffraction. A vibrating sample magnetometer was used to survey the samples' magnetic properties. The deposited carbon shell substantially affected the growth and magnetic properties of the CFNPs. Micro-Raman spectroscopy was used to study the carbon coating and revealed that the deposited carbon comprised graphite, multiwalled carbon nanotubes, and diamond- like carbon. With an increase in coating time, the intensity ratio between the amorphous and ordered peaks in the Raman spectra decreased, which indicated an increase in crystallite size.

  14. Medication Adherence in Patients with Bipolar Disorder: A Comprehensive Review.

    Science.gov (United States)

    Levin, Jennifer B; Krivenko, Anna; Howland, Molly; Schlachet, Rebecca; Sajatovic, Martha

    2016-09-01

    Poor medication adherence is a pervasive problem that causes disability and suffering as well as extensive financial costs among individuals with bipolar disorder (BD). Barriers to adherence are numerous and cross multiple levels, including factors related to bipolar pathology and those unique to an individual's circumstances. External factors, including treatment setting, healthcare system, and broader health policies, can also affect medication adherence in people with BD. Fortunately, advances in research have suggested avenues for improving adherence. A comprehensive review of adherence-enhancement interventions for the years 2005-2015 is included. Specific bipolar adherence-enhancement approaches that target knowledge gaps, cognitive patterns, specific barriers, and motivation may be helpful, as may approaches that capitalize on technology or novel drug-delivery systems. However, much work remains to optimally facilitate long-term medication adherence in people with BD. For adherence-enhancement approaches to be widely adapted, they need to be easily accessible, affordable, and practical. PMID:27435356

  15. Predictors of Low Clopidogrel Adherence Following Percutaneous Coronary Intervention

    OpenAIRE

    Muntner, Paul; Mann, Devin M.; Woodward, Mark; Choi, James W.; Stoler, Robert C; Shimbo, Daichi; Farkouh, Michael E.; Kim, Michael C.

    2011-01-01

    Few data are available on factors associated with low adherence or early clopidogrel discontinuation following percutaneous coronary intervention (PCI). Patients (n=284) were evaluated prior to hospital discharge following PCI to identify factors associated with low adherence to clopidogrel 30 days later. Pre-PCI adherence to daily medications was assessed using the 8-item Morisky Medication Adherence Scale (MMAS-8) and categorized as low, medium, or high (scores

  16. Improving adherence to medical regimens for juvenile rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Lindsley Carol B

    2007-05-01

    Full Text Available Abstract Poor adherence to medical regimens can compromise the efficacy of treatments for children and adolescents with juvenile rheumatoid arthritis (JRA. The purpose of this review is to describe medical regimens for the treatment of JRA and the rates of adherence to these regimens. We also summarize and critically the few research studies aimed at improving adherence to regimens for JRA. Finally, we summarize strategies for enhancing adherence in clinical practice.

  17. Supporting patients : pharmacy based interventions to improve medication adherence

    OpenAIRE

    Kooij, M. J.

    2015-01-01

    For many patients it is not easy to adhere to the agreed treatment with medication. Adherence has been defined as “the extent to which a person’s behaviour - taking medication - corresponds with agreed recommendations from a health care provider”. Numerous factors influence this taking behaviour and non-adherence must not be seen as the patients’ problem only. Health care providers, including pharmacists, should support patients to adhere. The overall aim of this thesis was to evaluate interv...

  18. Adherence to Diet in Youth with Type 1 Diabetes

    OpenAIRE

    Patton, Susana R.

    2011-01-01

    This paper reviewed current findings on dietary adherence in youth with type 1 diabetes mellitus (T1DM), discussed factors predicting dietary adherence, and presented directions for future research. The search terms were: type 1 diabetes mellitus; youth (0-22 years); diet; dietary adherence; nutrition; dietary intake; obesity; and complications. The studies involved youth with T1DM, presented dietary adherence data specifically, and/or described usual dietary patterns in youth. Articles that ...

  19. Understanding how adherence goals promote adherence behaviours: a repeated measure observational study with HIV seropositive patients

    Directory of Open Access Journals (Sweden)

    Jones Gareth

    2012-08-01

    Full Text Available Abstract Background The extent to which patients follow treatments as prescribed is pivotal to treatment success. An exceptionally high level (> 95% of HIV medication adherence is required to suppress viral replication and protect the immune system and a similarly high level (> 80% of adherence has also been suggested in order to benefit from prescribed exercise programmes. However, in clinical practice, adherence to both often falls below the desirable level. This project aims to investigate a wide range of psychological and personality factors that may lead to adherence/non-adherence to medical treatment and exercise programmes. Methods HIV positive patients who are referred to the physiotherapist-led 10-week exercise programme as part of the standard care are continuously recruited. Data on social cognitive variables (attitude, intention, subjective norms, self-efficacy, and outcome beliefs about the goal and specific behaviours, selected personality factors, perceived quality of life, physical activity, self-reported adherence and physical assessment are collected at baseline, at the end of the exercise programme and again 3 months later. The project incorporates objective measures of both exercise (attendance log and improvement in physical measures such as improved fitness level, weight loss, improved circumferential anthropometric measures and medication adherence (verified by non-invasive hair analysis. Discussion The novelty of this project comes from two key aspects, complemented with objective information on exercise and medication adherence. The project assesses beliefs about both the underlying goal such as following prescribed treatment; and about the specific behaviours such as undertaking the exercise or taking the medication, using both implicit and explicit assessments of patients’ beliefs and attitudes. We predict that i the way people think about the underlying goal of their treatments explains medication and exercise

  20. Evaluation of medication adherence in Lebanese hypertensive patients.

    Science.gov (United States)

    Yassine, Mohammad; Al-Hajje, Amal; Awada, Sanaa; Rachidi, Samar; Zein, Salam; Bawab, Wafa; Bou Zeid, Mayssam; El Hajj, Maya; Salameh, Pascale

    2016-09-01

    Controlling hypertension is essential in cardiovascular diseases. Poor medication adherence is associated with poor disease outcomes, waste of healthcare resources, and contributes to reduced blood pressure control. This study evaluates treatment adherence to antihypertensive therapy in Lebanese hypertensive patients by estimating the proportion of adherent hypertensive patients using a validated tool and investigates what factors predict this behavior. A questionnaire-based cross-sectional study was conducted on a random sample of 210 hypertensive outpatients selected from clinics located in tertiary-care hospitals and from private cardiology clinics located in Beirut. Adherence level was measured using a validated 8-item Modified Morisky Medication Adherence Scale (MMMAS). Among 210 patients, 50.5% showed high adherence, 27.1% medium adherence, and 22.4% low adherence to medication. Mean MMMAS score was 6.59±2.0. In bivariate analyses, having controlled blood pressure (p=0.003) and taking a combination drug (p=0.023) were predictors of high adherence. Forgetfulness (p<0.01), complicated drug regimen (p=0.001), and side effects (p=0.006) were predictors of low adherence after multiple liner regression. Logistic regression results showed that calcium channel blockers (p=0.030) were associated with increased adherence levels. In conclusion, developing multidisciplinary intervention programs to address the factors identified, in addition to educational strategies targeting healthcare providers, are necessary to enhance patient adherence. PMID:26232704

  1. Adhesion Forces and Composition of Planktonic and Adhering Oral Microbiomes

    NARCIS (Netherlands)

    Wessel, S. W.; Chen, Y.; Maitra, A.; van den Heuvel, E. R.; Slomp, A. M.; Busscher, H. J.; van der Mei, H. C.

    2014-01-01

    The oral microbiome consists of a planktonic microbiome residing in saliva and an adhering microbiome (the biofilm adhering to oral hard and soft tissues). Here we hypothesized that possible differences in microbial composition of the planktonic and adhering oral microbiome on teeth can be related t

  2. Measuring adherence to treatment of paediatric HIV/AIDS.

    Science.gov (United States)

    Naar-King, S; Frey, M; Harris, M; Arfken, C

    2005-04-01

    Parent, child, physician report and pill counts were used to measure adherence in paediatric HIV. Relationships to viral load were assessed. Pill counts were considered invalid. Adherence measures did not correlate with one another. Physicians reported lower adherence than parents, but parent and physician report correlated with viral load. The clinical and research utility of the various measures are discussed.

  3. Ethical Questions in Medical Electronic Adherence Monitoring.

    Science.gov (United States)

    Campbell, Jeffrey I; Eyal, Nir; Musiimenta, Angella; Haberer, Jessica E

    2016-03-01

    Electronic adherence monitors (EAMs) record and report an array of health behaviors, ranging from taking daily medications to wearing medical devices. EAMs are utilized in research worldwide and are being investigated for clinical use. However, there is also growing popular concern about the extent to which electronic devices may be used to monitor individuals, including allegations in the media that EAMs represent a move towards "Big Brother" in medicine. Here, we highlight the unique benefits as well as the potential ethical challenges that electronic adherence monitoring generates. These challenges surround autonomy, privacy and confidentiality, trust, and ancillary care obligations. We describe key questions within each of these domains that warrant further investigation, and present potential solutions to many of the concerns raised. PMID:26358284

  4. Subpopulations in purified platelets adhering on glass.

    Science.gov (United States)

    Donati, Alessia; Gupta, Swati; Reviakine, Ilya

    2016-01-01

    Understanding how platelet activation is regulated is important in the context of cardiovascular disorders and their management with antiplatelet therapy. Recent evidence points to different platelet subpopulations performing different functions. In particular, procoagulant and aggregating subpopulations have been reported in the literature in platelets treated with the GPVI agonists. How the formation of platelet subpopulations upon activation is regulated remains unclear. Here, it is shown that procoagulant and aggregating platelet subpopulations arise spontaneously upon adhesion of purified platelets on clean glass surfaces. Calcium ionophore treatment of the adhering platelets resulted in one platelet population expressing both the procoagulant and the adherent population markers phosphatidylserine and the activated form of GPIIb/IIIa, while all of the platelets expressed CD62P independently of the ionophore treatment. Therefore, all platelets have the capacity to express all three activation markers. It is concluded that platelet subpopulations observed in various studies reflect the dynamics of the platelet activation process. PMID:27338300

  5. Medication adherence among older adults with schizophrenia.

    Science.gov (United States)

    Leutwyler, Heather C; Fox, Patrick J; Wallhagen, Margaret

    2013-02-01

    Older adults with schizophrenia are a growing segment of the population, yet their physical and mental health status is extremely poor. This article presents findings from a qualitative study that explored the understanding older adults with schizophrenia have of their physical health status. The study was conducted among 28 older adults with schizophrenia from a variety of settings using semi-structured interviews and participant observation. Self-management of psychiatric and non-psychiatric medications and its effect on participants' health status was one of the central themes that emerged from the study. Different styles of medication adherence were identified and factors associated with each style are presented. The findings provide insights into the design of clinical interventions aimed at promoting medication adherence among older adults with schizophrenia.

  6. Can adherence to antihypertensive therapy be used to promote adherence to statin therapy?

    Directory of Open Access Journals (Sweden)

    Richard H Chapman

    2009-08-01

    Full Text Available Richard H Chapman1, Elise M Pelletier1, Paula J Smith1, Craig S Roberts21US Health Economics and Outcomes Research, IMS Health, Falls Church, VA, USA; 2Global Outcomes Research, Pfizer Inc, New York, NY, USAObjective: To compare adherence with statin therapy in patients switching to single-pill amlodipine besylate/atorvastatin calcium with patients adding a separate statin to their amlodipine regimen.Methods: We identified hypertensive patients prescribed amlodipine who switched to amlodipine/atorvastatin (switch or added a statin to their amlodipine regimen (add-on from July 2004 to June 2007. Propensity score matching (1 switch:3 add-on was applied based on ‘nearest neighbor’ approach. The primary adherence measure was patients with proportion of days covered (PDC ≥0.80 at 180 days; secondary measures included mean PDC and persistence. A sensitivity analysis was performed, accounting for total statin/amlodipine exposure.Results: Among 4556 matched patients (n = 1139 switch; n = 3417 add-on, mean age was 53.9 years and 52.1% were male. After 180 days, adherence with statin therapy was higher for the switch vs add-on cohort (50.8% vs 44.3%; P < 0.001. After adjusting for pre-index amlodipine adherence, the switch cohort was more likely to be adherent than the add-on cohort (odds ratio: 1.64 [95% confidence interval: 1.42 to 1.89]. Persistence was higher in the switch than the add-on cohort (127.6 vs 117 days; P < 0.001.Conclusion: Hypertensive patients taking amlodipine who initiated statin therapy via single-pill amlodipine/atorvastatin were more likely to remain adherent to their statin than patients adding a separate statin to their antihypertensive regimen.Keywords: adherence, amlodipine, atorvastatin, cardiovascular disease, persistence, single-pill

  7. Concordance of adherence measurement using self-reported adherence questionnaires and medication monitoring devices.

    Science.gov (United States)

    Shi, Lizheng; Liu, Jinan; Koleva, Yordanka; Fonseca, Vivian; Kalsekar, Anupama; Pawaskar, Manjiri

    2010-01-01

    The primary objective of this review was to identify and examine the literature on the association between medication adherence self-reported questionnaires (SRQs) and medication monitoring devices. The primary literature search was performed for 1980-2009 using PubMed, PubMed In Process and Non-Indexed, Ovid MEDLINE, Ovid MEDLINE In-Process, PsycINFO (EBSCO), CINAHL (EBSCO), Ovid HealthStar, EMBASE (Elsevier) and Cochrane Databases and using the following search terms: 'patient compliance', 'medication adherence', 'treatment compliance', 'drug monitoring', 'drug therapy', 'electronic', 'digital', 'computer', 'monitor', 'monitoring', 'drug', 'drugs', 'pharmaceutical preparations', 'compliance' and 'medications'. We identified studies that included SRQs and electronic monitoring devices to measure adherence and focused on the SRQs that were found to be moderately to highly correlated with the monitoring devices. Of the 1679 citations found via the primary search, 41 full-text articles were reviewed for correlation between monitoring devices and SRQs. A majority (68%) of articles reported high (27%), moderate (29%) or significant (12%) correlation between monitoring devices (37 using Medication Event Monitoring System [MEMS®] and four using other devices) and SRQs (11 identified and numerous other unnamed SRQs). The most commonly used SRQs were the Adult/Pediatric AIDS Clinical Trial Group (AACTG/PACTG; 24.4%, 10/41) followed by the 4-item Morisky (9.8%, 4/41), Brief Medication Questionnaire (9.8%, 4/41) and visual analogue scale (VAS; 7.3%, 3/41). Although study designs differed across the articles, SRQs appeared to report a higher rate of medication adherence (+14.9%) than monitoring devices. In conclusion, several medication adherence SRQs were validated using electronic monitoring devices. A majority of them showed high or moderate correlation with medication adherence measured using monitoring devices, and could be considered for measuring patient

  8. Adherence to asthma guidelines in general practices.

    Science.gov (United States)

    Roghmann, M C; Sexton, M

    1999-06-01

    Adherence to asthma practice guidelines is low. Improved compliance could potentially improve care of patients with asthma. The purpose of this study was to determine if patients managed in a general practice with an associated asthma clinic are more likely to use asthma medications according to clinical practice guidelines than patients managed in the general surgery of the practice. A cross-sectional study of adult asthmatics, aged 18-55 years, was conducted in six British general practices. Prescription data on all asthma medication was collected for a 6-month period. Information on asthma clinic attendance, age, sex, employment status, other medical illness, and how patients used their inhaled beta2-agonist was collected through questionnaire. The prescription data for asthma medication and patient use of inhaled beta2-agonist were compared to the British Thoracic Society's (BTS) Guidelines for Management of Asthma in Adults to determine if the patient's asthma medication regimen was appropriate. There was no significant association found between appropriate asthma medication and asthma clinic attendance or other patient characteristics. Adherence to the BTS guidelines was low. Fifty-eight percent of the asthma patients used asthma medication regimens that were not consistent with the BTS guidelines published 1 year earlier. Adherence to the BTS guidelines was low regardless of patient characteristics, including asthma clinic attendance, age, sex, employment status, other medical illness, or individual practice. These findings underscore the need to document the utility of clinical practice guidelines which may improve physician compliance.

  9. Adherent Raindrop Modeling, Detectionand Removal in Video.

    Science.gov (United States)

    You, Shaodi; Tan, Robby T; Kawakami, Rei; Mukaigawa, Yasuhiro; Ikeuchi, Katsushi

    2016-09-01

    Raindrops adhered to a windscreen or window glass can significantly degrade the visibility of a scene. Modeling, detecting and removing raindrops will, therefore, benefit many computer vision applications, particularly outdoor surveillance systems and intelligent vehicle systems. In this paper, a method that automatically detects and removes adherent raindrops is introduced. The core idea is to exploit the local spatio-temporal derivatives of raindrops. To accomplish the idea, we first model adherent raindrops using law of physics, and detect raindrops based on these models in combination with motion and intensity temporal derivatives of the input video. Having detected the raindrops, we remove them and restore the images based on an analysis that some areas of raindrops completely occludes the scene, and some other areas occlude only partially. For partially occluding areas, we restore them by retrieving as much as possible information of the scene, namely, by solving a blending function on the detected partially occluding areas using the temporal intensity derivative. For completely occluding areas, we recover them by using a video completion technique. Experimental results using various real videos show the effectiveness of our method. PMID:26485475

  10. Hybrid carbon nanomaterials for electrochemical detection of biomolecules

    Science.gov (United States)

    Laurila, Tomi

    2015-09-01

    Electrochemical detection of different biomolecules in vivo is a promising path towards in situ monitoring of human body and its functions. However, there are several major obstacles, such as sensitivity, selectivity and biocompatiblity, which must be tackled in order to achieve reliably and safely operating sensor devices. Here we show that by utilizing hybrid carbon materials as electrodes to detect two types of neurotransmitters, dopamine and glutamate, several advantages over commonly used electrode materials can be achieved. In particular, we will demonstrate here that it is possible to combine the properties of different carbon allotropes to obtain hybrid materials with greatly improved electrochemical performance. Three following examples of the approach are given: (i) diamond-like carbon (DLC) thin film electrodes with different layer thicknesses, (ii) multi-walled carbon nanotubes grown directly on top of DLC and (iii) carbon nanofibres synthesized on top of DLC thin films. Detailed structural and electrochemical characterization is carried out to rationalize the reasons behind the observed behvior. In addition, results from the atomistic simulations are utilized to obtain more information about the properties of the amorphous carbon thin films.

  11. [Adherence to chronic medication: also a frequent problem in Belgium!].

    Science.gov (United States)

    Liekens, S; Hulshagen, L; Dethier, M; Laekeman, G; Foulon, V

    2013-12-01

    Medication adherence in chronic conditions such as asthma, type 2 diabetes, heart failure, HIV and cancer appears to be a frequent problem. However, the literature on adherence in patients who use inhaled corticosteroids (ICS), oral hypoglycemic agents, drugs for heart failure, antiretrovirals or oral chemotherapy, contains little or no relevant data for Belgium. In the context of a Master thesis in Pharmaceutical care at KU Leuven, a quantitative study was performed to determine the prevalence of adherence to chronic medication in Belgium. This retrospective, cross-sectional study used a database containing refill data of a regional pharmacists' association (KLAV). Out of the 603 pharmacies affiliated with this association, all 50 pharmacies where HIV medication was delivered, were selected. Dispensing data from the selected pharmacies were collected from 01/07/2008 to 31/12/2009 for five pathologies, i.e.; asthma, type 2 diabetes, heart failure, HIV and cancer. Adherence (TT) was calculated with the Medication Refill Adherence (MRA) method. In order to determine whether there were associations between age, gender, drug class and adherence, Chi-square tests were used. Compared with the other patients, cancer patients were the most adherent in taking their drugs (median adherence rate = 88%). In addition, this was the only group in which the median adherence rate was above the set limit of 80%. The patients who were prescribed inhaled corticosteroids were the least adherent (median adherence rate = 38%). More than 50% of patients with asthma/COPD, heart failure and diabetes were classified as "under-users". Furthermore, the results showed a significant association within asthma patients between gender and adherence. In asthma, type 2 diabetes, heart failure and HIV patients there was a significant relationship between age and adherence and drug class and adherence. As the current study has some limitations, the results should be handled with caution. Nevertheless

  12. Adherence to physical and mental activity interventions: Coping plans as a mediator and prior adherence as a moderator.

    NARCIS (Netherlands)

    Evers, A.W.M.; Klusmann, V.; Schwarzer, R.; Heuser, I.

    2012-01-01

    Objective. Adherence to behavioural intervention programmes is a necessary condition for beneficial outcomes to be achieved. This study tested whether social cognitive variables and coping plans predict adherence. Design and methods. Adherence was examined in a randomized controlled trial with healt

  13. Adherence to inhaled therapy, mortality and hospital admission in COPD

    DEFF Research Database (Denmark)

    Vestbo, J; Anderson, J A; Calverley, P M A;

    2009-01-01

    between adherence and mortality remained unchanged and statistically significant after adjusting for other factors related to prognosis (hazard ratio 0.40 (95% CI 0.35 to 0.46), p... adherence and hospital admission remained unchanged and significant in a multivariate analysis (rate ratio 0.58 (95% CI 0.44 to 0.73, p... was more pronounced in patients with good adherence than in those with poor adherence. CONCLUSION: Adherence to inhaled medication is significantly associated with reduced risk of death and admission to hospital due to exacerbations in COPD. Further research is needed to understand these strong...

  14. Adherence Characteristics of Cement Clinker on Basic Bricks

    Institute of Scientific and Technical Information of China (English)

    GUO Zongqi; Michel Rigaud

    2002-01-01

    Based on the sandwich test, adherence mechanisms of cement clinker on various basic bricks were tackled by microstructural observations with help of cathodoluminescence technique. Doloma based bricks offer sufficient lime to react with clinker, forming C3 S rich layer and initializing superior adherence. However, clinker with low silica ratio leads to MgO agglomeration at the interface of doloma bricks, which reduces adherence strength. On magnesia spinel bricks, fine, crystalline spinel easily reacts with lime containing phases from clinker to form lowmelting phases and belite zone, which shows high adherence performance. Lack of fine spinel in magnesia spinel bricks results in poor adherence.

  15. Adherence of Helicobacter pylori to the Gastric Mucosa

    Directory of Open Access Journals (Sweden)

    Marguerite Clyne

    1997-01-01

    Full Text Available Bacterial adhesion to the intestinal epithelium is a critical initial step in the pathogenesis of many enteric diseases. Helicobacter pylori is a duodenal pathogen that adheres to the gastric epithelium and causes gastritis and peptic ulceration. The mechanism by which H pylori causes disease has not yet been elucidated but adherence to the gastric mucosa is thought to be an important virulence determinant of the organism. What is known about adherence of H pylori to the gastric mucosa is summarized. Topics discussed are the mechanism of H pylori adherence; in vitro and in vivo models of H pylori infection; and adherence and potential adhesins and receptors for H pylori.

  16. Sharia Adherence Mosque Survey: Correlations between Sharia Adherence and Violent Dogma in U.S. Mosques

    Directory of Open Access Journals (Sweden)

    Mordechai Kedar

    2011-12-01

    Full Text Available A random survey of 100 representative mosques in the U.S. was conducted to measure the correlation between Sharia adherence and dogma calling for violence against non-believers.  Of the 100 mosques surveyed, 51% had texts on site rated as severely advocating violence; 30% had texts rated as moderately advocating violence; and 19% had no violent texts at all.  Mosques that presented as Sharia adherent were more likely to feature violence-positive texts on site than were their non-Sharia-adherent counterparts.  In 84.5% of the mosques, the imam recommended studying violence-positive texts.  The leadership at Sharia-adherent mosques was more likely to recommend that a worshipper study violence-positive texts than leadership at non-Sharia-adherent mosques.  Fifty-eight percent of the mosques invited guest imams known to promote violent jihad.  The leadership of mosques that featured violence-positive literature was more likely to invite guest imams who were known to promote violent jihad than was the leadership of mosques that did not feature violence-positive literature on mosque premises.  

  17. Controlled Deposition and Alignment of Carbon Nanotubes

    Science.gov (United States)

    Smits, Jan M. (Inventor); Wincheski, Russell A. (Inventor); Patry, JoAnne L. (Inventor); Watkins, Anthony Neal (Inventor); Jordan, Jeffrey D. (Inventor)

    2012-01-01

    A carbon nanotube (CNT) attraction material is deposited on a substrate in the gap region between two electrodes on the substrate. An electric potential is applied to the two electrodes. The CNT attraction material is wetted with a solution defined by a carrier liquid having carbon nanotubes (CNTs) suspended therein. A portion of the CNTs align with the electric field and adhere to the CNT attraction material. The carrier liquid and any CNTs not adhered to the CNT attraction material are then removed.

  18. Experimental investigation of dropwise condensation of steam on diamond-like carbonate and thick fluor-containing organic films%类金刚石和厚有机膜促进水蒸气滴状冷凝传热的实验研究

    Institute of Scientific and Technical Information of China (English)

    马学虎; 朱晓波; 安家明; 陈嘉宾

    2003-01-01

    为了寻找适宜的表面处理技术制备能长期地维持滴状冷凝传热型态,实验研究了垂直黄铜管外类金刚石和含氟有机薄膜水蒸气常压下冷凝传热特性.两种表面均能促进水蒸气的滴状冷凝型态,但类金刚石表面上液滴形状较扁,脱落频率不高,而有机膜表面的液滴形状、大小以及脱落频率均优于类金刚石表面.在管内冷却水雷诺数为1.0×104~2.0×105时,类金刚石和含氟有机薄膜表面的热流密度和冷凝传热系数分别为485~807 kW/m2和18~23 kW/(m2@K)、171~330 kW/m2和4.8~7.2 kW/(m2@K).含氟有机薄膜表面表现了优良的涂层结合强度,寿命实验已经持续了近10个月.

  19. PMMA树脂义齿表面沉积类金刚石碳膜改善耐磨性的研究%A Study to Improve the Function of Wear-resistance of PMMA Resin Denture Through Depositing the Film of Diamond Like Carbon on the Surface

    Institute of Scientific and Technical Information of China (English)

    马丽丽; 杨喜昆; 李智刚; 朱发坤; 钱天才; 刘磊; 何祥

    2003-01-01

    目的在PMMA树脂义齿表面沉积类金刚石碳(DLC)膜改善义齿的耐磨性能.方法采用真空阴极镀膜方法在PMMA树脂及义齿表面沉积DLC膜,应用光电子能谱仪及喇曼光谱仪确定为DLC膜,通过沉积DLC膜及未沉积DLC膜树脂样品的显微硬度测试、耐磨试验及耐磨试验前后磨痕宽度的测定,观察结果进行统计学处理.结果镀膜与未镀膜PMMA树脂试件显微硬度、磨痕宽度经统计学检验差异有显著性,经显微观察镀膜后PMMA树脂试件磨痕浅而窄,未镀膜试件磨痕深而宽.结论 PMMA树脂义齿表面沉积DLC膜能显著改善耐磨性.

  20. RF-PCVD低温沉积无色透明类金刚石保护膜的工艺研究%Study on the process parameters of colorless transparent diamond-like carbon (DLC) films deposited by RF-PCVD

    Institute of Scientific and Technical Information of China (English)

    朱霞高; 侯惠君; 林松盛; 袁镇海; 戴达煌

    2006-01-01

    采用磁约束增强射频辉光放电等离子体辅助化学气相沉积法(RF-PCVD)低温沉积出无色透明的类金刚石保护膜(DLC),主要研究了炉压P0、射频功率Pf、自生负偏压Uz、磁感应强度B、电极间距d、反应气体、镀膜时间t等工艺参数对成膜的影响.试验结果表明,外加磁场B制约了带电粒子逃逸出电极空间,提高了反应气体的离化率及等离子体浓度和活性,并使非独立变量Pf和Uz成为独立变量,有利于工艺调节.当极间距大时,需适当提高Pf,Uz和C-H流量才可得到无色、较硬的DLC膜.在比功率密度大于0.009 W·cm-2·Pa-1、C-H浓度即体积分数0.9%~1.4%及膜厚小于90nm的条件下,可沉积出无色透明、硬度较高的DLC膜.

  1. Research on the Preparation of Cu-doped Diamond-like Carbon Nanodot Arrays and Their Excellent Field Emitting Properties%铜掺杂类金刚石纳米点阵列的制备及场发射性能研究

    Institute of Scientific and Technical Information of China (English)

    崇二敏; 李晓春; 李春; 闫鹏勋; 张鹏举; 刘洋; 范晓彦

    2008-01-01

    利用磁过滤等离子体结合氧化铝模板(AA0)技术在室温下制备了具有优异场发射性能的铜掺杂类金刚石(DLC)纳米点阵列.微观分析表明,铜掺杂类金刚石纳米点阵列分布均匀,密度高达109cm-2;利用X射线光电子能谱对制备的铜掺杂类金刚石纳米点阵列进行结构分析,测得铜的掺杂量为3.6%且sp3键含量高达60%;通过对铜掺杂类金刚石纳米点阵列的场发射性能测试,试验结果表明,铜掺杂类金刚石纳米点阵列开启电场和阈值电场分别为0.08V/μm,0.42V/μm,并且在电场值为0.67V/μm时,发射电流密度高达95mA/cm2,场发射性能明显优于无掺杂类金刚石纳米点阵列.

  2. Study on Micro-tribological Properties Diamond-like Carbon Films with FFM-Tip Size Effect%类金刚石薄膜微观摩擦性能的FFM评价——针尖尺度效应

    Institute of Scientific and Technical Information of China (English)

    范真; 丁建宁; 解国新; 凌智勇; 李长生

    2006-01-01

    采用等离子体增强气相沉积制备了类金刚石薄膜,利用原子力显微镜的轻敲模式观察了它们的形貌,并在考虑外加载荷和扫描速度的基础上,用摩擦力显微镜(FFM)对比考察了尖端探针和平头探针对类金刚石薄膜摩擦性能评价的影响.结果表明:类金刚石薄膜的表面粗糙度随基底负偏压的增加而减小;存在于探针和类金刚石薄膜之间的水膜对尖端探针的剪切阻力贡献较大,且尖端探针测得的摩擦力变化趋势受扫描速度影响显著;水膜对平头探针起着不同形式的润滑作用,从而导致平头探针和类金刚石薄膜之间摩擦性能的速度效应存在差异;利用摩擦力显微镜考察类金刚石薄膜的摩擦性能时,存在着明显的针尖尺寸效应.

  3. Adherence to antiretroviral therapy among people living with HIV

    Directory of Open Access Journals (Sweden)

    Basavaprabhu Achappa

    2013-01-01

    Full Text Available Background: Acquired immune deficiency syndrome (AIDS is now considered as a manageable chronic illness. There has been a dramatic reduction in human immunodeficiency virus (HIV related morbidity and mortality due to antiretroviral therapy. A high level of adherence (>95% is required for antiretroviral therapy to be effective. There are many barriers to adherence in both developed and developing countries. Aim: The aim of our study was to determine adherence levels and factors influencing adherence to antiretroviral therapy among people living with HIV. Materials and Methods: Using a cross-sectional study design, 116 HIV positive patients receiving antiretroviral therapy for at least 1 year were interviewed using a semi structured questionnaire. The collected data was analyzed using Statistical Product and Service Solutions (SPSS version 11.5. Chi-square test was done. A P value of < 0.05 was considered statistically significant. Results: Of 116 participants, 63.7% reported adherence ≥ 95%. Mean adherence index was 91.25%. Financial constraints, forgetting to take medication, lack of family care, depression, alcohol use, social stigma and side effects to antiretroviral therapy were barriers for adherence in our study. Conclusion: Adherence to antiretroviral therapy in south India is suboptimal. Intensive adherence counseling should be provided to all patients before initiation ofantiretroviral therapy. Health care providers must identify possible barriers to adherence at the earliest and provide appropriate solutions.

  4. Medication adherence among transgender women living with HIV.

    Science.gov (United States)

    Baguso, Glenda N; Gay, Caryl L; Lee, Kathryn A

    2016-08-01

    Medication adherence is linked to health outcomes among adults with HIV infection. Transgender women living with HIV (TWLWH) in the US report suboptimal adherence to medications and are found to have difficulty integrating HIV medication into their daily routine, but few studies explore the factors associated with medication adherence among transgender women. Thus, the purpose of this paper is to examine demographic and clinical factors related to self-reported medication adherence among transgender women. This secondary analysis is based on data collected from the Symptom and Genetic Study that included a convenience sample of 22 self-identified transgender women, 201 non-transgender men, and 72 non-transgender women recruited in northern California. Self-reported medication adherence was assessed using the AIDS Clinical Trials Group Adherence Questionnaire. Gender differences in demographic and clinical variables were assessed, as were differences between transgender women reporting high and low adherence. Transgender women had lower adherence to medications compared to non-transgender males and non-transgender females (p = .028) and were less likely to achieve viral suppression (p = .039). Within the transgender group, Black/African-Americans reported better adherence than participants who were Whites/Caucasian or other races (p = .009). Adherence among transgender women was unrelated to medication count and estrogen therapy, but consistent with other reports on the HIV population as a whole; transgender women with high adherence were more likely to achieve viral suppression compared to the transgender women with low adherence. Despite the high incidence of HIV infection in the transgender population, few studies focus on TWLWH, either in regard to their adherence to antiretroviral therapies or to their healthcare in general. To address ongoing health disparities, more studies are needed focusing on the transgender population's continuum of care in

  5. An assessment of adherence to basic ecological principles by payments for ecosystem service projects.

    Science.gov (United States)

    Prager, C M; Varga, A; Olmsted, P; Ingram, J C; Cattau, M; Freund, C; Wynn-Grant, R; Naeem, S

    2016-08-01

    Programs and projects employing payments for ecosystem service (PES) interventions achieve their objectives by linking buyers and sellers of ecosystem services. Although PES projects are popular conservation and development interventions, little is known about their adherence to basic ecological principles. We conducted a quantitative assessment of the degree to which a global set of PES projects adhered to four ecological principles that are basic scientific considerations for any project focused on ecosystem management: collection of baseline data, identification of threats to an ecosystem service, monitoring, and attention to ecosystem dynamics or the formation of an adaptive management plan. We evaluated 118 PES projects in three markets-biodiversity, carbon, and water-compiled using websites of major conservation organizations; ecology, economic, and climate-change databases; and three scholarly databases (ISI Web of Knowledge, Web of Science, and Google Scholar). To assess adherence to ecological principles, we constructed two scientific indices (one additive [ASI] and one multiplicative [MSI]) based on our four ecological criteria and analyzed index scores by relevant project characteristics (e.g., sector, buyer, seller). Carbon-sector projects had higher ASI values (P water-sector projects and marginally higher ASI scores (P budget. These findings suggest, at this critical phase in the rapid growth of PES projects, that fundamental ecological principles should be considered more carefully in PES project design and implementation in an effort to ensure PES project viability and sustainability. PMID:26502915

  6. Using communication skills to improve adherence in children with chronic disease : The adherence equation

    NARCIS (Netherlands)

    Brand, Paul L. P.; Klok, Ted; Kaptein, Adrian A.

    2013-01-01

    Nonadherence to maintenance medication is common in paediatric chronic conditions. Despite the common belief that nonadherence is therapy-resistant, and the apparent lack of evidence for successful interventions to improve adherence, there is, in fact, a considerable body of evidence suggesting that

  7. Adherence to HAART : processes explaining adherence behavior in acceptors and non-acceptors

    NARCIS (Netherlands)

    Vervoort, Sigrid C. J. M.; Grypdonck, Mieke H. F.; de Grauwe, Annelies; Hoepelman, Andy I. M.; Borleffs, Jan C. C.

    2009-01-01

    In order to explore and clarify the underlying processes which lead to (non)-adherence behavior in patients treated with highly active antiretroviral therapy (HAART), a qualitative study was conducted. Thirty-seven in-depth interviews were held with 30 Caucasian HIV-positive patients. Additional dat

  8. Automated microinjection system for adherent cells

    Science.gov (United States)

    Youoku, Sachihiro; Suto, Yoshinori; Ando, Moritoshi; Ito, Akio

    2007-07-01

    We have developed an automated microinjection system that can handle more than 500 cells an hour. Microinjection injects foreign agents directly into cells using a micro-capillary. It can randomly introduce agents such as DNA, proteins and drugs into various types of cells. However, conventional methods require a skilled operator and suffer from low throughput. The new automated microinjection techniques we have developed consist of a Petri dish height measuring method and a capillary apex position measuring method. The dish surface height is measured by analyzing the images of cells that adhere to the dish surface. The contrast between the cell images is minimized when the focus plane of an object lens coincides with the dish surface. We have developed an optimized focus searching method with a height accuracy of +/-0.2 um. The capillary apex position detection method consists of three steps: rough, middle, and precise. These steps are employed sequentially to cover capillary displacements of up to +/-2 mm, and to ultimately accomplish an alignment accuracy of less than one micron. Experimental results using this system we developed show that it can introduce fluorescent material (Alexa488) into adherent cells, HEK293, with a success rate of 88.5%.

  9. Statistical Dynamics of Religions and Adherents

    CERN Document Server

    Ausloos, M; Ausloos, Marcel; Petroni, Filippo

    2006-01-01

    Religiosity is one of the most important sociological aspects of populations. All religions may evolve in their beliefs and adapt to the society developments. A religion is a social variable, like a language or wealth, to be studied like any other organizational parameter. Several questions can be raised, as considered in this study: e.g. (i) from a ``macroscopic'' point of view : How many religions exist at a given time? (ii) from a ``microscopic'' view point: How many adherents belong to one religion? Does the number of adherents increase or not, and how? No need to say that if quantitative answers and mathematical laws are found, agent based models can be imagined to describe such non-equilibrium processes. It is found that empirical laws can be deduced and related to preferential attachment processes, like on evolving network; we propose two different algorithmic models reproducing as well the data. Moreover, a population growth-death equation is shown to be a plausible modeling of evolution dynamics in a...

  10. Adherence to methotrexate in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Bliddal, Henning; Eriksen, Stine A; Christensen, Robin;

    2015-01-01

    Objectives. To study adherence to methotrexate (MTX) and factors of importance thereof in patients with rheumatoid arthritis (RA). Methods. Patients with a hospital diagnosis of RA (ICD10 codes M05.X or M06.X) after January 1, 1997, and aged ≥18 years at the date of first diagnosis....../contact, with at least one prescription of MTX (L04AX03), were included. Results. A total of 18,703 (47.6%) patients had ever used MTX among 39,286 with a diagnosis of RA; among the MTX users, 16,503 (88.2%) had filed more than one MTX prescription. The median time from diagnosis to first MTX prescription was 0.66 (IQR...... 0.26-1.80) years. In those who filed more than one MTX prescription, the mean adherence time for ≥7.5 mg MTX per week was 1,925 (IQR 467-3,056) days for patients treated in private practice versus 1,892 (IQR 452-3,316) days for patients treated in hospital. The main determinants of nonadherence were...

  11. Accurate reporting of adherence to inhaled therapies in adults with cystic fibrosis: methods to calculate normative adherence

    Directory of Open Access Journals (Sweden)

    Hoo ZH

    2016-05-01

    Full Text Available Zhe Hui Hoo,1,2 Rachael Curley,1,2 Michael J Campbell,1 Stephen J Walters,1 Daniel Hind,3 Martin J Wildman1,2 1School of Health and Related Research (ScHARR, University of Sheffield, 2Sheffield Adult Cystic Fibrosis Centre, Northern General Hospital, 3Sheffield Clinical Trials Research Unit, University of Sheffield, Sheffield, UK Background: Preventative inhaled treatments in cystic fibrosis will only be effective in maintaining lung health if used appropriately. An accurate adherence index should therefore reflect treatment effectiveness, but the standard method of reporting adherence, that is, as a percentage of the agreed regimen between clinicians and people with cystic fibrosis, does not account for the appropriateness of the treatment regimen. We describe two different indices of inhaled therapy adherence for adults with cystic fibrosis which take into account effectiveness, that is, “simple” and “sophisticated” normative adherence. Methods to calculate normative adherence: Denominator adjustment involves fixing a minimum appropriate value based on the recommended therapy given a person’s characteristics. For simple normative adherence, the denominator is determined by the person’s Pseudomonas status. For sophisticated normative adherence, the denominator is determined by the person’s Pseudomonas status and history of pulmonary exacerbations over the previous year. Numerator adjustment involves capping the daily maximum inhaled therapy use at 100% so that medication overuse does not artificially inflate the adherence level. Three illustrative cases: Case A is an example of inhaled therapy under prescription based on Pseudomonas status resulting in lower simple normative adherence compared to unadjusted adherence. Case B is an example of inhaled therapy under-prescription based on previous exacerbation history resulting in lower sophisticated normative adherence compared to unadjusted adherence and simple normative adherence

  12. Side effects, adherence self-efficacy, and adherence to antiretroviral treatment: a mediation analysis in a Chinese sample.

    Science.gov (United States)

    Zhang, Liying; Li, Xiaoming; Lin, Zhenping; Jacques-Tiura, Angela J; Xu, Jinping; Zhou, Yuejiao; Qiao, Shan; Shen, Zhiyong; Stanton, Bonita

    2016-07-01

    Antiretroviral therapy (ART) is a lifelong treatment. To date, ART adherence is suboptimal for most patients in resource-poor settings. Previous research indicates that medication side effects are perceived to be a significant barrier of high ART adherence. Data regarding the role of adherence self-efficacy in mediating the relationship between side effects from ART and adherence to ART are limited; thus, this study examines this potential mediational role of self-efficacy. A cross-sectional survey of 2987 people living with HIV aged ≥18 years was conducted in 2012-2013 in Guangxi Autonomous Region (Guangxi) which has one of the fastest-growing HIV rates in China. Of the total sample, 2146 (72.1%) participants had initiated ART. Participants reported the number of days of completing the daily dose of ART in the past month; adherence was defined as completing the daily dose at least 28 days in the last month (≥90%). Side effects were significantly negatively related to adherence to ART. Mediation analyses indicated that adherence self-efficacy significantly mediated the side effects-adherence relationship. Future interventions to increase adherence self-efficacy and effective coping with side effects among HIV patients are needed in order to improve their ART adherence.

  13. [e-Health interventions and improvement in treatment adherence].

    Science.gov (United States)

    Sieben, Angelien; Bredie, S J H Bas; van Laarhoven, C J H M Kees; Schoonhoven, Lisette; Burger, David M; van Onzenoort, Hein A W

    2014-01-01

    Poor adherence to medication is one of the most important determinants in the treatment of patients with chronic disorders. e-Health-based interventions may be able to improve treatment adherence. This article gives an overview of the available e-Health interventions and the extent to which they can improve adherence. We searched in the PubMed, Cinahl, PsycInfo, and Embase databases for e-Health interventions that aimed at improving adherence to treatment. Of the 16 included studies, 15 used a website and one used an app. Ten studies showed a significant improvement in treatment adherence by using the intervention. e-Health interventions were generally complex. Simple interventions were the most successful in improving treatment adherence.

  14. Electrochemical Corrosion Behavior of the DLC Coated and Uncoated NiTi Alloys

    Institute of Scientific and Technical Information of China (English)

    Jiehe SUI; Wei CAI; Liancheng ZHAO

    2006-01-01

    A dense and well-adhered diamond-like carbon(DLC)coating was prepared on the nickel-titanium(NiTi)alloys by plasma immersion ion implantation and deposition(PⅢD). Potentiodynamic polarization tests indicated the corrosion resistance of the NiTi alloys was markedly improved by the DLC coating. The Ni ions release of the NiTi alloys was effectively blocked by the DLC coating.

  15. Health Literacy Explains Racial Disparities in Diabetes Medication Adherence

    OpenAIRE

    Osborn, Chandra Y; Cavanaugh, Kerri; Wallston, Kenneth A.; Kripalani, Sunil; White, Richard O.; Elasy, Tom A.; Rothman, Russell L.

    2011-01-01

    While low health literacy and suboptimal medication adherence are more prevalent in racial/ethnic minority groups than Whites, little is known about the relationship between these factors in adults with diabetes, and whether health literacy or numeracy might explain racial/ethnic disparities in diabetes medication adherence. Previous work in HIV suggests health literacy mediates racial differences in adherence to anti-retroviral treatment, but no study to date has explored numeracy as a media...

  16. Characterization of the adherence properties of Streptococcus salivarius.

    OpenAIRE

    Weerkamp, A H; McBride, B C

    1980-01-01

    The adherence and aggregation properties of 46 human oral Streptococcus salivarius isolates were examined. A total of 41% of the isolates aggregated with whole human saliva, 50% aggregated with human erythrocytes, and 85% adhered to human buccal epithelial cells. Strains that aggregated with saliva and erythrocytes usually reacted with Streptococcus group K typing serum whereas the non-hemagglutinating strains did not. K+ strains also adhered more strongly to human buccal epithelial cells tha...

  17. Treatment adherence among adolescents with epilepsy: what really matters?

    OpenAIRE

    Carbone, Loretta; Zebrack, Bradley; Plegue, Melissa; Joshi, Sucheta; Shellhaas, Renée

    2013-01-01

    Treatment adherence is often suboptimal among adolescents with epilepsy. Yet knowledge is lacking regarding factors that affect adherence. Empirical studies and theories of human development suggest that self-management skills, self-efficacy, and sense of control are related to adherence. Eighty-eight adolescents with epilepsy, and their parents, completed standardized measures assessing epilepsy knowledge and expectations, treatment self-management, sense of control, and self-efficacy. Bette...

  18. Adherence of Helicobacter pylori to primary human gastrointestinal cells.

    OpenAIRE

    Clyne, M.; Drumm, B

    1993-01-01

    Helicobacter pylori adheres only to gastric cells in vivo. However, the organism adheres to a wide variety of nongastric cells in vitro. In this study, we have used flow cytometry to assess the adherence of H. pylori to primary epithelial cells isolated from gastric, duodenal, and colonic biopsy specimens by collagenase digestion. After incubation of bacteria and cells together and subsequent staining with a two-stage fluorescein isothiocyanate-labelled H. pylori antibody method, cells with a...

  19. Denial and Acceptance Coping Styles and Medication Adherence in Schizophrenia

    OpenAIRE

    Aldebot, Stephanie; Weisman de Mamani, Amy G.

    2009-01-01

    Antipsychotics are often the first line of treatment for individuals with schizophrenia (Fialko et al., 2008). One challenge to effective treatment is lack of adherence to prescribed medication. Lower rates of adherence are associated with considerably higher rates of relapse and poorer course of illness. Therefore studying characteristics that may be related to medication adherence is important. Coping styles may be one such factor. Individuals utilize a variety of coping mechanisms to manag...

  20. Acute lymphoblastic leukemia: Are Egyptian children adherent to maintenance therapy?

    OpenAIRE

    Elhamy Rifky Abdel Khalek; Laila M Sherif; Naglaa Mohamed Kamal; Gharib, Amal F.; H M Shawky

    2015-01-01

    Background, Aims, Settings and Design: Poor adherence to oral maintenance chemotherapy can cause relapse of acute lymphoblastic leukemia (ALL). A multicenter study for the evaluation of adherence to oral 6-mercaptopurine (6-MP) maintenance chemotherapy for childhood ALL in Egypt to identify contributing factors and possible steps to promote adherence. Materials and Methods: The study included 129 children with ALL in complete remission receiving 6-MP single daily oral dose in the evening....

  1. Enhanced tunnel transport in disordered carbon superlattice structures incorporated with nitrogen

    Science.gov (United States)

    Katkov, Mikhail V.; Bhattacharyya, Somnath

    2012-06-01

    The possibility for enhanced tunnel transport through the incorporation of nitrogen in a quasi-one dimensional superlattice structure of amorphous carbon (a -C) made of sp2-C and sp3-C rich phases is shown by using a tight-binding model. The proposed superstructure can be described by a set of disordered graphite-like carbon clusters (acting as quantum wells) separated by a thin layer of diamond-like carbon (barriers) where the variation of the width and depth of the carbon clusters significantly control the electron transmission peaks. A large structural disorder in the pure carbon system, introduced through the variation of the bond length and associated deformation potential for respective carbon phases, was found to suppress the sharp features of the transmission coefficients. A small percentage of nitrogen addition to the carbon clusters can produce a distinct transmission peak at the low energy; however, it can be practically destroyed due to increase of the level of disorder of carbon sites. Whereas pronounced resonance peaks, both for C and N sites can be achieved through controlling the arrangement of the nitrogen sites of increased concentration within the disordered sp2-C clusters. The interplay of disorder associated with N and C sites illustrated the tunable nature of resistance of the structures as well as their characteristic times.

  2. Impact of prescription size on statin adherence and cholesterol levels

    Directory of Open Access Journals (Sweden)

    Mehler Phillip S

    2007-10-01

    Full Text Available Abstract Background Therapy with 3-Hydroxy-3-methylglutaryl Co-enzyme A reductase inhibitors (statins improve outcomes in a broad spectrum of patients with hyperlipidemia. However, effective therapy requires ongoing medication adherence; restrictive pharmacy policies may represent a barrier to successful adherence, particularly among vulnerable patients. In this study we sought to assess the relationship between the quantity of statin dispensed by the pharmacy with patient adherence and total cholesterol. Methods We analyzed a cohort of 3,386 patients receiving more than one fill of statin medications through an integrated, inner-city health care system between January 1, 2000 and December 31, 2002. Our measure of adherence was days of drug acquisition divided by days in the study for each patient, with adequate adherence defined as ≥ 80%. Log-binomial regression was used to determine the relative risk of various factors, including prescription size, on adherence. We also assessed the relationship between adherence and total cholesterol using multiple linear regression. Results After controlling for age, gender, race, co-payment, comorbidities, and insurance status, patients who obtained a majority of fills as 60-day supply compared with 30-day supply were more likely to be adherent to their statin medications (RR 1.41, 95% CI 1.28–1.55, P Conclusion In a healthcare system serving predominantly indigent patients, the provision of a greater quantity of statin medication at each prescription fill contributes to improved adherence and greater drug effectiveness.

  3. The effect of reminder systems on patients' adherence to treatment

    Directory of Open Access Journals (Sweden)

    Fenerty SD

    2012-02-01

    Full Text Available Sarah D Fenerty1, Cameron West1, Scott A Davis1, Sebastian G Kaplan3, Steven R Feldman1,2,41Center for Dermatology Research, Department of Dermatology, 2Department of Pathology, 3Department of Psychiatry and Behavioral Medicine, 4Department of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USABackground: Patient adherence is an important component of the treatment of chronic disease. An understanding of patient adherence and its modulating factors is necessary to correctly interpret treatment efficacy and barriers to therapeutic success.Purpose: This meta-analysis aims to systematically review published randomized controlled trials of reminder interventions to assist patient adherence to prescribed medications.Methods: A Medline search was performed for randomized controlled trials published between 1968 and June 2011, which studied the effect of reminder-based interventions on adherence to self-administered daily medications.Results: Eleven published randomized controlled trials were found between 1999 and 2009 which measured adherence to a daily medication in a group receiving reminder interventions compared to controls receiving no reminders. Medication adherence was measured as the number of doses taken compared to the number prescribed within a set period of time. Meta-analysis showed a statistically significant increase in adherence in groups receiving a reminder intervention compared to controls (66.61% versus 54.71%, 95% CI for mean: 0.8% to 22.4%. Self-reported and electronically monitored adherence rates did not significantly differ (68.04% versus 63.67%, P = 1.0. Eight of eleven studies showed a statistically significant increase in adherence for at least one of the reminder group arms compared to the control groups receiving no reminder intervention.Limitations: The data are limited by imperfect measures of adherence due to variability in data collection methods. It is also likely

  4. Adherence to antiretroviral therapy: are we doing enough?

    Science.gov (United States)

    Read, T; Mijch, A; Fairley, C K

    2003-01-01

    Adherence to antiretroviral therapy is a powerful predictor of response to therapy. For optimal antiretroviral therapy response, individuals need to take more than 95% of their prescribed medication. The most widely used method for measuring adherence is self-report of the number of missed doses and this should be done at every clinic visit. There are several well-recognized predictors of poor adherence, such as illicit drug use, depression, limited knowledge or ambivalence about starting treatment. Adherence can be improved by addressing these issues or through other means such as pill boxes or electronic reminders. PMID:12752896

  5. Tuberculosis treatment adherence and fatality in Spain

    Directory of Open Access Journals (Sweden)

    Vidal Rafael

    2009-12-01

    Full Text Available Abstract Background The adherence to long tuberculosis (TB treatment is a key factor in TB control programs. Always some patients abandon the treatment or die. The objective of this study is to identify factors associated with defaulting from or dying during antituberculosis treatment. Methods Prospective study of a large cohort of TB cases diagnosed during 2006-2007 by 61 members of the Spanish Society of Pneumology and Thoracic Surgery (SEPAR. Predictive factors of completion outcome (cured plus completed treatment vs. defaulters plus lost to follow-up and fatality (died vs. the rest of patients were based on logistic regression, calculating odds ratios (OR and 95% confidence intervals (CI. Results Of the 1490 patients included, 29.7% were foreign-born. The treatment outcomes were: cured 792 (53.2%, completed treatment 540 (36.2%, failure 2 (0.1%, transfer-out 33 (2.2%, default 27 (1.8%, death 27 (1.8%, lost to follow-up 65 (4.4%, other 4 (0.3%. Completion outcome reached 93.5% and poor adherence was associated with: being an immigrant (OR = 2.03; CI:1.06-3.88, living alone (OR = 2.35; CI:1.05-5.26, residents of confined institutions (OR = 4.79; CI:1.74-13.14, previous treatment (OR = 2.93; CI:1.44-5.98, being an injecting drug user (IDU (OR = 9.51; CI:2.70-33.47 and treatment comprehension difficulties (OR = 2.93; CI:1.44-5.98. Case fatality was 1.8% and it was associated with the following variables: age 50 or over (OR = 10.88; CI:1.12-105.01, retired (OR = 12.26;CI:1.74-86.04, HIV-infected (OR = 9.93; CI:1.48-66.34, comprehension difficulties (OR = 4.07; CI:1.24-13.29, IDU (OR = 23.59; CI:2.46-225.99 and Directly Observed Therapy (DOT (OR = 3.54; CI:1.07-11.77. Conclusion Immigrants, those living alone, residents of confined institutions, patients treated previously, those with treatment comprehension difficulties, and IDU patients have poor adherence and should be targeted for DOT. To reduce fatality rates, stricter monitoring is required

  6. Adherence to COPD guidelines in general practice

    DEFF Research Database (Denmark)

    Ulrik, Charlotte Suppli; Sørensen, Tina Brandt; Højmark, Torben Brunse;

    2013-01-01

    BACKGROUND: The general practitioner (GP) is often the first healthcare contact for patients with chronic obstructive pulmonary disease (COPD). AIMS: To determine whether participating in a standardised educational programme delivered in the GP's own practice is associated with adherence to COPD...... guidelines. METHODS: A nationwide register-based observational before and after study was undertaken with a control group of propensity-matched practices (follow-up period 6 months). COPD was defined as age 40+ years and at least two prescriptions for inhaled medication. The educational programme consisted...... were used to compare the rate of spirometry testing, preventive consultations, and influenza vaccinations provided to COPD patients and the rate of spirometry testing in non-COPD individuals, assumed to reflect diagnostic activity. RESULTS: Data for 102 participating GP practices were analysed...

  7. Sister Carrie, an Adherent of Desires

    Institute of Scientific and Technical Information of China (English)

    裴水妹

    2007-01-01

    Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.

  8. Patient adherence to medical treatment. A review of reviews.

    NARCIS (Netherlands)

    Dulmen, S. van; Sluijs, E.; Dijk, L. van; Ridder, D. de; Heerdink, R.; Bensing, J.

    2007-01-01

    BACKGROUND: Patients' non-adherence to medical treatment remains a persistent problem. Many interventions to improve patient adherence are unsuccessful and sound theoretical foundations are lacking. Innovations in theory and practice are badly needed. A new and promising way could be to review the e

  9. Bromide as marker for drug adherence in hypertensive patients.

    NARCIS (Netherlands)

    Braam, R.L.; Uum, S.H.M. van; Lenders, J.W.M.; Thien, Th.

    2008-01-01

    WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Insufficient drug adherence is an important reason for inadequate blood pressure control. Currently, methods that measure drug adherence objectively are lacking. Objective methods are needed to help improve blood pressure control and outcome in hypertensive

  10. Towards tailored and targeted adherence assessment to optimise asthma management

    NARCIS (Netherlands)

    van Boven, Job F. M.; Trappenburg, Jaap C. A.; van der Molen, Thys; Chavannes, Niels H.

    2015-01-01

    In this paper, we aim to emphasise the need for a more comprehensive and tailored approach to manage the broad nature of non-adherence, to personalise current asthma management. Although currently several methods are available to measure the extent of asthma patients' adherence, the vast majority do

  11. Variation in guideline adherence in intrauterine insemination care.

    Science.gov (United States)

    Haagen, Esther C; Nelen, Willianne L D M; Grol, Richard P T M; Braat, Didi D M; Hermens, Rosella P M G; Kremer, Jan A M

    2010-04-01

    Health-care delivery according to clinical practice guidelines is thought to be critical in achieving optimal outcomes. This study aimed to assess the extent to which practice performance in intrauterine insemination (IUI) care is consistent with guideline recommendations and to evaluate the association between guideline adherence and outcome of IUI care. In a retrospective cohort study, 1100 infertile couples who underwent IUI treatment at 10 Dutch hospitals were asked to grant access to their medical record for assessment of guideline adherence using 25 systematically developed guideline-based performance indicators. A total of 558 couples who started 2334 IUI cycles participated. Guideline adherence regarding 20 process and five structure aspects of IUI care was often substandard and varied considerably between hospitals. Out of 10 possible associations investigated, guideline adherence regarding sperm quality and guideline adherence regarding the total number of IUI cycles were associated with improved ongoing pregnancy rates after IUI. Thus, guideline adherence in IUI care is far from optimal and varies substantially between hospitals. As associations between guideline adherence and ongoing pregnancy after IUI were mainly non-significant, further research is needed to evaluate associations between guideline adherence and other outcomes of IUI care besides ongoing pregnancy, such as patient safety and cost effectiveness. PMID:20129823

  12. 14 CFR 1260.72 - Adherence to original budget estimates.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Adherence to original budget estimates. 1260.72 Section 1260.72 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Post-Award Requirements § 1260.72 Adherence to original budget estimates....

  13. Reliability of assessment of adherence to an antimicrobial treatment guideline

    NARCIS (Netherlands)

    Mol, PGM; Gans, ROB; Panday, PVN; Degener, JE; Laseur, M; Haaijer-Ruskamp, FM

    2005-01-01

    Assessment procedures for adherence to a guideline must be reliable and credible. The aim of this study was to explore the reliability of assessment of adherence, taking account of the professional backgrounds of the observers. A secondary analysis explored the impact of case characteristics on asse

  14. 42 CFR 447.304 - Adherence to upper limits; FFP.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Adherence to upper limits; FFP. 447.304 Section 447... Noninstitutional Services § 447.304 Adherence to upper limits; FFP. (a) The Medicaid agency must not pay more than... payments may be made only up to the reasonable charge under Medicare. (c) FFP is not available for a...

  15. Sublingual immunotherapy in youngsters : adherence in a randomized clinical trial

    NARCIS (Netherlands)

    Roder, E.; Berger, M. Y.; de Groot, H.; van Wijk, R. Gerth

    2008-01-01

    Background Adherence is essential for effective treatment. Although several trials on the efficacy of sublingual immunotherapy (SLIT) in youngsters have been published, few contain data on medication intake. Objective We aimed to quantify adherence both to study protocol and medication intake as wel

  16. Development of adherence metrics for caloric restriction interventions

    Science.gov (United States)

    Objective measures are needed to quantify dietary adherence during caloric restriction (CR) while participants are freeliving. One method to monitor adherence is to compare observed weight loss to the expected weight loss during a prescribed level of CR. Normograms (graphs)of expected weight loss ca...

  17. Development of adherence metrics for caloric restriction interventions

    Science.gov (United States)

    Objective measures are needed to quantify dietary adherence during caloric restriction (CR) while participants are freeliving. One method to monitor adherence is to compare observed weight loss to the expected weight loss during a prescribed level of CR. Normograms (graphs) of expected weight loss c...

  18. Cognitive-Behavioral Therapy for HIV Medication Adherence and Depression

    Science.gov (United States)

    Safren, Steven A.; Hendriksen, Ellen S.; Mayer, Kenneth H.; Mimiaga, Matthew J.; Pickard, Robert; Otto, Michael W.

    2004-01-01

    For patients with HIV, depression is a common, distressing condition that can interfere with a critical self-care behavior--adherence to antiretroviral therapy. The present study describes a cognitive-behavioral treatment designed to integrate cognitive-behavioral therapy for depression with our previously tested approach to improving adherence to…

  19. Novel phase of carbon, ferromagnetism, and conversion into diamond

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Jagdish, E-mail: narayan@ncsu.edu; Bhaumik, Anagh [Department of Materials Science and Engineering, Centennial Campus, North Carolina State University, Raleigh, North Carolina 27695-7907 (United States)

    2015-12-07

    We report the discovery of a new phase of carbon (referred to as Q-carbon) and address fundamental issues related to direct conversion of carbon into diamond at ambient temperatures and pressures in air without any need for catalyst and presence of hydrogen. The Q-carbon is formed as result of quenching from super undercooled state by using high-power nanosecond laser pulses. We discuss the equilibrium phase diagram (P vs. T) of carbon and show that by rapid quenching kinetics can shift thermodynamic graphite/diamond/liquid carbon triple point from 5000 K/12 GPa to super undercooled carbon at atmospheric pressure in air. It is shown that nanosecond laser heating of diamond-like amorphous carbon on sapphire, glass, and polymer substrates can be confined to melt carbon in a super undercooled state. By quenching the carbon from the super undercooled state, we have created a new state of carbon (Q-carbon) from which nanodiamond, microdiamond, microneedles, and single-crystal thin films are formed depending upon the nucleation and growth times allowed for diamond formation. The Q-carbon quenched from liquid is a new state of solid carbon with a higher mass density than amorphous carbon and a mixture of mostly fourfold sp{sup 3} (75%–85%) with the rest being threefold sp{sup 2} bonded carbon (with distinct entropy). It is expected to have new and improved mechanical hardness, electrical conductivity, chemical, and physical properties, including room-temperature ferromagnetism (RTFM) and enhanced field emission. Here we present interesting results on RTFM, enhanced electrical conductivity and surface potential of Q-carbon to emphasize its unique properties. The Q-carbon exhibits robust bulk ferromagnetism with estimated Curie temperature of about 500 K and saturation magnetization value of 20 emu g{sup −1}. From the Q-carbon, diamond phase is nucleated and a variety of micro- and nanostructures and large-area single-crystal diamond sheets are grown by allowing

  20. Novel phase of carbon, ferromagnetism, and conversion into diamond

    Science.gov (United States)

    Narayan, Jagdish; Bhaumik, Anagh

    2015-12-01

    We report the discovery of a new phase of carbon (referred to as Q-carbon) and address fundamental issues related to direct conversion of carbon into diamond at ambient temperatures and pressures in air without any need for catalyst and presence of hydrogen. The Q-carbon is formed as result of quenching from super undercooled state by using high-power nanosecond laser pulses. We discuss the equilibrium phase diagram (P vs. T) of carbon and show that by rapid quenching kinetics can shift thermodynamic graphite/diamond/liquid carbon triple point from 5000 K/12 GPa to super undercooled carbon at atmospheric pressure in air. It is shown that nanosecond laser heating of diamond-like amorphous carbon on sapphire, glass, and polymer substrates can be confined to melt carbon in a super undercooled state. By quenching the carbon from the super undercooled state, we have created a new state of carbon (Q-carbon) from which nanodiamond, microdiamond, microneedles, and single-crystal thin films are formed depending upon the nucleation and growth times allowed for diamond formation. The Q-carbon quenched from liquid is a new state of solid carbon with a higher mass density than amorphous carbon and a mixture of mostly fourfold sp3 (75%-85%) with the rest being threefold sp2 bonded carbon (with distinct entropy). It is expected to have new and improved mechanical hardness, electrical conductivity, chemical, and physical properties, including room-temperature ferromagnetism (RTFM) and enhanced field emission. Here we present interesting results on RTFM, enhanced electrical conductivity and surface potential of Q-carbon to emphasize its unique properties. The Q-carbon exhibits robust bulk ferromagnetism with estimated Curie temperature of about 500 K and saturation magnetization value of 20 emu g-1. From the Q-carbon, diamond phase is nucleated and a variety of micro- and nanostructures and large-area single-crystal diamond sheets are grown by allowing growth times as needed

  1. Health Games - Modern Tools for Enhancing Patient Adherence

    Directory of Open Access Journals (Sweden)

    Sameer Bhaskar GOKHALE

    2015-06-01

    Full Text Available Low patient adherence remains a major public health challenge globally and imposes a considerable economic burden on healthcare systems. It is critical to develop an effective intervention to improve patient adherence. Factors such as physician-patient relation, patient's health literacy, attitude, cultural variations, and patient’s involvement in decision making are responsible for improving adherence. Information technology has revolutionized almost all industries including healthcare but its use has not shown its full promise to boost adherence. Recent developments in smart phone market penetration, gamification, and easy to navigate user experience have made it possible for healthcare providers to effectively connect with patients using innovative ways enabled by technology. Leveraging on this fact, healthcare industry should be focusing on development and use of interactive health games. Indication-wise games can be developed in collaboration with physicians, academics, thought leaders and experienced media companies. In summary, gamification mayeffectively be used to improve patient adherence.

  2. Interventional tools to improve medication adherence: review of literature

    Science.gov (United States)

    Costa, Elísio; Giardini, Anna; Savin, Magda; Menditto, Enrica; Lehane, Elaine; Laosa, Olga; Pecorelli, Sergio; Monaco, Alessandro; Marengoni, Alessandra

    2015-01-01

    Medication adherence and persistence is recognized as a worldwide public health problem, particularly important in the management of chronic diseases. Nonadherence to medical plans affects every level of the population, but particularly older adults due to the high number of coexisting diseases they are affected by and the consequent polypharmacy. Chronic disease management requires a continuous psychological adaptation and behavioral reorganization. In literature, many interventions to improve medication adherence have been described for different clinical conditions, however, most interventions seem to fail in their aims. Moreover, most interventions associated with adherence improvements are not associated with improvements in other outcomes. Indeed, in the last decades, the degree of nonadherence remained unchanged. In this work, we review the most frequent interventions employed to increase the degree of medication adherence, the measured outcomes, and the improvements achieved, as well as the main limitations of the available studies on adherence, with a particular focus on older persons. PMID:26396502

  3. Carbon-based tribofilms from lubricating oils.

    Science.gov (United States)

    Erdemir, Ali; Ramirez, Giovanni; Eryilmaz, Osman L; Narayanan, Badri; Liao, Yifeng; Kamath, Ganesh; Sankaranarayanan, Subramanian K R S

    2016-08-01

    Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid 'tribofilms', which together ensure easy slippage and long wear life. The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant's anti-wear additive (typically zinc dialkyldithiophosphate). Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids. Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon. Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon-carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm. PMID:27488799

  4. Carbon-based tribofilms from lubricating oils

    Science.gov (United States)

    Erdemir, Ali; Ramirez, Giovanni; Eryilmaz, Osman L.; Narayanan, Badri; Liao, Yifeng; Kamath, Ganesh; Sankaranarayanan, Subramanian K. R. S.

    2016-08-01

    Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid ‘tribofilms’, which together ensure easy slippage and long wear life. The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant’s anti-wear additive (typically zinc dialkyldithiophosphate). Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids. Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon. Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon-carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm.

  5. Limits to the adherence of oxide scales

    International Nuclear Information System (INIS)

    Fracture mechanics is used to identify criteria under which uniform oxide scales may be expected to fail due to rapidly applied strains. The most common failure mode occurs when the strain, ε, builds up in the scale until the strain energy density per unit area exceeds the fracture surface energy, γ, of the oxide. This produces spalling when ε > (2γ/hE)1/2, where h is the scale thickness and E is the oxide Youngs modulus. In thin scales, as the external strain is applied to the oxide via the metal substrate, it is clear that no further strain can be applied to the oxide if the substrate has itself been strained beyond yield. This gives rise to extended oxide adherence in which the oxide cracks and forms a series of islands but remains attached to the deformed metal. When the oxide thickness is less than its comminution limit, the flaw size necessary for brittle fracture exceeds the oxide thickness and the oxide yields in a ductile manner without cracking. The results are presented as maps of failure strain versus oxide thickness for various oxide systems such as Fe3O4, Cr2O3, Al2O3, SiO2 and NiO. The observed cases of spalling are found to lie within the predicted regions. (author)

  6. Putting the Brakes on Carbon

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    More Chinese are adhering to a low-carbon lifestyle Han Xiangyu hesitates every day on whether he should climb the stairs or take the elevator to his 12th-floor apartment. He also ruminates on what tem-perature to set the thermostat and whether he should take a car or bus to go shopping.

  7. Hemocompatibility of DLC coatings synthesized by ion beam assisted deposition

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Ion beam-assisted diamond-like carbon (DLC) coatings have beenused for growing the human platelet, fibrinogen, and albumin in the control environment in order to assess their hemocompatibility. The hard carbon films were prepared on polymethylmethacrylate (PMMA) at room temperature using ion beam assisted deposition (IBAD). Raman spectroscopic analysis proved that the carbon films on PMMA are diamond-like with a higher fraction of sp\\+3 bonds in the structure of mixed sp\\+2+sp\\+3 bonding. The blood protein adsorption tests showed that DLC coatings can adsorb more albumin and are slightly more fibrinogen than the PMMA chosen as a control sample. The platelets adhered on DLC coatings were reduced significantly in number. These results indicate good hemocompatibility of DLC coatings.

  8. [Concept analysis of medication adherence in patients with chronic disease].

    Science.gov (United States)

    Huang, Jen-Ying; Chen, Hsing-Mei

    2014-06-01

    Pharmacotherapy plays an important role in the management of chronic diseases. However, many patients with chronic disease do not adhere to their medication regimen. This results in worsening symptoms and frequent re-hospitalizations. As a result, healthcare providers may view these patients as bad. Medication adherence is a complex concept. Analyzing this concept may assist nurses to improve patient-centered care. This paper uses Walker & Avant's method to conduct a concept analysis of medication adherence. Results show the defining attributes of medication adherence as: (1) knowing and agreeing to the medication; (2) communicating and negotiating the regimen; and (3) active, continuous involvement in and appraisal of the treatment effect. Identified antecedents of medication adherence included the patient having: (1) a prescribed medication regimen; (2) cognitive and action abilities in her / his role as a patient; and (3) level of preparation for medication treatment. Identified consequences of medication adherence include: (1) improving symptom control; (2) decreasing re-hospitalizations and mortality; (3) reducing medical care costs; (4) restoring self-esteem; and (5) diminishing depression. It is hoped that this concept analysis provides a reference for nurses to achieve a better understanding of medication adherence and further improve nursing practice. PMID:24899565

  9. Adherence to lipid-lowering treatment: the patient perspective

    Directory of Open Access Journals (Sweden)

    Casula M

    2012-11-01

    Full Text Available Manuela Casula,1 Elena Tragni,1 Alberico Luigi Catapano1,21Epidemiology and Preventive Pharmacology Centre (SEFAP, Department of Pharmacological Sciences, University of Milan, Milan, Italy; 2IRCCS MultiMedica, Sesto San Giovanni, ItalyAbstract: Despite the widespread prescription of highly effective lipid-lowering medications, such as the HMG-CoA reductase inhibitors (statins, a large portion of the population has lipid levels higher than the recommended goals. Treatment failures have been attributed to a variety of causes but the most important is likely to be poor adherence to therapy in the form of irregular or interrupted intake and the high frequency of discontinuation or lack of persistence. Adherence is a multidimensional phenomenon determined by the interplay of patient factors, physician factors, and health care system factors. Patients' knowledge and beliefs about their illness, motivation to manage it, confidence in their ability to engage in illness-management behaviors, and expectations regarding the outcome of treatment and the consequences of poor adherence interact to influence adherence behavior. Patient-related factors account for the largest incremental explanatory power in predicting adherence. This article provides an overview of this critical issue, focusing on patient role in determining adherence level to lipid-lowering therapy.Keywords: hyperlipidemia/drug therapy, medication adherence, patient preference, health behavior

  10. Challenges of treatment adherence in older patients with Parkinson's disease.

    Science.gov (United States)

    Bainbridge, Jacquelyn L; Ruscin, J Mark

    2009-01-01

    Patient adherence to a medication regimen is critical to treatment outcome, quality of life and future healthcare costs. For elderly patients with Parkinson's disease, obstacles to adherence can be particularly complex. Beyond age-related and economic factors, elderly patients with Parkinson's disease often require complicated dosing or titration schedules and have multiple co-morbidities that necessitate administration of therapies from multiple drug classes. In addition, neuropsychiatric disturbances and cognitive impairment, which are often part of the disease process, can affect adherence, as can variable responses to anti-parkinsonian agents as the disease progresses. Several recent studies in patients with Parkinson's disease point to the need for establishing good adherence patterns early and maintaining these throughout the course of treatment. To achieve optimal adherence in elderly patients with Parkinson's disease, a combination of pharmacological and non-pharmacological approaches appears to be the best strategy for success. Examples include a strong provider-patient relationship, educational intervention by phone or face-to-face contact, simplified dosing and administration schedules, management and understanding of medication adverse events, and the use of adherence aids such as pill boxes and hour-by-hour organizational charts. Research into new avenues that include improved drug monitoring, pharmacogenetics and neuroprotective regimens may give rise to better adherence in elderly patients with Parkinson's disease in the future. PMID:19220071

  11. Factors affecting adherence to a raw vegan diet.

    Science.gov (United States)

    Link, Lilli B; Jacobson, Judith S

    2008-02-01

    The purpose of this study was to evaluate adherence and identify predictors of adherence to a raw vegan diet (i.e., uncooked plant foods) following a stay at a raw vegan institute. In this cohort study of guests at a raw vegan institute, subjects completed written questionnaires upon arrival and 12 weeks later. Of 107 eligible guests, 84 participated. Mean age was 54 years, 23 were male, and 73 white. Fifty-one completed the 12-week follow-up. Eight (16%) reported their diet to be 80% raw vegan at baseline and 14 (28%) at follow-up. Based on a raw vegan dietary adherence score (range 0-42) created for this study, mean adherence (SD) increased from 15.1 (5.4) to 17.0 (5.8) over 12 weeks (p=0.03). Baseline predictors of adherence included: education (beta=0.95), severity of disease (beta=0.98), and self-efficacy to adhere (beta=0.72). Future interventions that evaluate this diet should address self-efficacy, an important, potentially remediable predictor of adherence.

  12. Spillover adherence effects of fixed-dose combination HIV therapy

    Directory of Open Access Journals (Sweden)

    Kauf TL

    2012-02-01

    Full Text Available Teresa L Kauf1, Keith L Davis2, Stephanie R Earnshaw2, E Anne Davis31Department of Pharmaceutical Outcomes and Policy, College of Pharmacy, University of Florida, Gainesville, FL, 2RTI Health Solutions, Research Triangle Park, NC, 3Independent consultant, Pittsboro, NC, USAAbstract: The impact of fixed-dose combination (FDC products on adherence to other, non-fixed regimen components has not been examined. We compared adherence to a third antiretroviral (ART component among patients receiving a nucleoside reverse transcriptase inhibitor (NRTI backbone consisting of the FDC Epzicom®, GlaxoSmithKline Inc, Research Triangle Park, NC (abacavir sulfate 600 mg + lamivudine 300 mg; FDC group versus NRTI combinations taken as two separate pills (NRTI Combo group using data from a national sample of 30 health plans covering approximately 38 million lives from 1997 to 2005. Adherence was measured as the medication possession ratio (MPR. Multivariate logistic regression compared treatment groups based on the likelihood of achieving ≥95% adherence, with sensitivity analyses using alternative thresholds. MPR was assessed as a continuous variable using multivariate linear regression. Covariates included age, gender, insurance payer type, year of study drug initiation, presence of mental health and substance abuse disorders, and third agent class. The study sample consisted of 650 FDC and 1947 NRTI Combo patients. Unadjusted mean adherence to the third agent was higher in the FDC group than the NRTI Combo group (0.92 vs 0.85; P < 0.0001. In regression analyses, FDC patients were 48% and 39% more likely to achieve 95% and 90% third agent adherence, respectively (P ≤ 0.03. None of the other MPR specifications achieved comparable results. Among managed care patients, use of an FDC appears to substantially improve adherence to a third regimen component and thus the likelihood of achieving the accepted standard for adherence to HIV therapy of 95%.Keywords

  13. Fewer Bacteria Adhere to Softer Hydrogels.

    Science.gov (United States)

    Kolewe, Kristopher W; Peyton, Shelly R; Schiffman, Jessica D

    2015-09-01

    Clinically, biofilm-associated infections commonly form on intravascular catheters and other hydrogel surfaces. The overuse of antibiotics to treat these infections has led to the spread of antibiotic resistance and underscores the importance of developing alternative strategies that delay the onset of biofilm formation. Previously, it has been reported that during surface contact, bacteria can detect surfaces through subtle changes in the function of their motors. However, how the stiffness of a polymer hydrogel influences the initial attachment of bacteria is unknown. Systematically, we investigated poly(ethylene glycol) dimethacrylate (PEGDMA) and agar hydrogels that were 20 times thicker than the cumulative size of bacterial cell appendages, as a function of Young's moduli. Soft (44.05-308.5 kPa), intermediate (1495-2877 kPa), and stiff (5152-6489 kPa) hydrogels were synthesized. Escherichia coli and Staphylococcus aureus attachment onto the hydrogels was analyzed using confocal microscopy after 2 and 24 h incubation periods. Independent of hydrogel chemistry and incubation time, E. coli and S. aureus attachment correlated positively to increasing hydrogel stiffness. For example, after a 24 h incubation period, there were 52 and 82% fewer E. coli adhered to soft PEGDMA hydrogels than to the intermediate and stiff PEGDMA hydrogels, respectively. A 62 and 79% reduction in the area coverage by the Gram-positive microbe S. aureus occurred after 24 h incubation on the soft versus intermediate and stiff PEGDMA hydrogels. We suggest that hydrogel stiffness is an easily tunable variable that could potentially be used synergistically with traditional antimicrobial strategies to reduce early bacterial adhesion and therefore the occurrence of biofilm-associated infections.

  14. A Review of the Effects of Medication Delivery Systems on Treatment Adherence in Children with Asthma

    OpenAIRE

    Cohn, Robert C.

    2003-01-01

    Background: A patient's adherence to an appropriate treatment regimen is necessary to minimize morbidity and mortality associated with childhood asthma. Many factors influence the success of treatment adherence.

  15. Copper and nickel adherently electroplated on titanium alloy

    Science.gov (United States)

    Brown, E. E.

    1967-01-01

    Anodic treatment of titanium alloy enables electroplating of tightly adherent coatings of copper and nickel on the alloy. The alloy is treated in a solution of hydrofluoric and acetic acids, followed by the electroplating process.

  16. Attrition and adherence in the online treatment of chronic insomnia.

    Science.gov (United States)

    Hebert, Elizabeth A; Vincent, Norah; Lewycky, Samantha; Walsh, Kaitlyn

    2010-01-01

    This study examined the ability of the Theory of Planned Behavior (TPB; Ajzen, 1985) and the Transtheoretical Model of Behavior Change (TTM; Prochaska & DiClemente, 1983) to explain adherence and attrition in an online treatment program for chronic insomnia. Responses to questionnaire measures of the TPB and TTM were used to predict adherence and dropout over the subsequent 5 weeks of treatment. Results showed that there was a 17% dropout rate and that perceived behavioral control, social support, and intention to complete the program were significantly associated with adherence to sleep hygiene homework. Attrition was predicted only by symptom severity and psychiatric comorbidity. Implications are that these models should be considered to maximize adherence. PMID:20582757

  17. Clinical pharmacist interventions to support adherence to thrombopreventive therapy

    DEFF Research Database (Denmark)

    Hedegaard, Ulla

    individualised interventions and team-based care, e.g. integrating a clinical pharmacist with particular focus on patients’ drug-related problems. One approach with growing evidence of improving medication adherence is motivational interviewing (MI). So far, no clinical pharmacist intervention using MI has......-based patient interview and three follow-up telephone calls. There was no difference in the primary outcome, the composite medication possession ratio (MPR) for antiplatelets, anticoagulants and statins during the year after hospitalisation, as assessed by analysing prescription refill records. At 12 months...... to the one in the first study, except that the patient interview was more structured using the Drug Adherence Work-up (DRAW) tool and an adherence questionnaire for identifying potential adherence and lifestyle-related problems. At 12 months, 20.3% of the patients in the intervention group (N=231) were non...

  18. Older Adults' Uptake and Adherence to Exercise Classes: Instructors' Perspectives.

    Science.gov (United States)

    Hawley-Hague, Helen; Horne, Maria; Skelton, Dawn A; Todd, Chris

    2016-01-01

    Exercise classes provide a range of benefits for older adults, but adherence levels are poor. We know little of instructors' experiences of delivering exercise classes to older adults. Semistructured interviews, informed by the Theory of Planned Behavior (TPB), were conducted with instructors (n = 19) delivering multicomponent exercise classes to establish their perspectives on older adults' uptake and adherence to exercise classes. Analysis revealed 'barriers' to uptake related to identity, choice/control, cost, and venue, and 'solutions' included providing choice/control, relating exercise to identity, a personal touch, and social support. Barriers to adherence included unrealistic expectations and social influences, and solutions identified were encouraging commitment, creating social cohesion, and an emphasis on achieving outcomes. Older adults' attitudes were an underlying theme, which related to all barriers and solutions. The instructor plays an important, but not isolated, role in older adults' uptake and adherence to classes. Instructors' perspectives help us to further understand how we can design successful exercise classes. PMID:26214265

  19. Method of detaching adherent cells for flow cytometry

    KAUST Repository

    Kaur, Mandeep

    2015-12-24

    In one aspect, a method for detaching adherent cells can include adding a cell lifting solution to the media including a sample of adherent cells and incubating the sample of adherent cells with the cell lifting solution. No scraping or pipetting is needed to facilitate cell detachment. The method do not require inactivation of cell lifting solution and no washing of detaching cells is required to remove cell lifting solution. Detached cells can be stained with dye in the presence of cell lifting solution and are further analyzed using flow cytometer. The method has been tested using 6 different cell lines, 4 different assays, two different plate formats (96 and 384 well plates) and two different flow cytometry instruments. The method is simple to perform, less time consuming, with no cell loss and makes high throughput flow cytometry on adherent cells a reality.

  20. Older Adults' Uptake and Adherence to Exercise Classes: Instructors' Perspectives.

    Science.gov (United States)

    Hawley-Hague, Helen; Horne, Maria; Skelton, Dawn A; Todd, Chris

    2016-01-01

    Exercise classes provide a range of benefits for older adults, but adherence levels are poor. We know little of instructors' experiences of delivering exercise classes to older adults. Semistructured interviews, informed by the Theory of Planned Behavior (TPB), were conducted with instructors (n = 19) delivering multicomponent exercise classes to establish their perspectives on older adults' uptake and adherence to exercise classes. Analysis revealed 'barriers' to uptake related to identity, choice/control, cost, and venue, and 'solutions' included providing choice/control, relating exercise to identity, a personal touch, and social support. Barriers to adherence included unrealistic expectations and social influences, and solutions identified were encouraging commitment, creating social cohesion, and an emphasis on achieving outcomes. Older adults' attitudes were an underlying theme, which related to all barriers and solutions. The instructor plays an important, but not isolated, role in older adults' uptake and adherence to classes. Instructors' perspectives help us to further understand how we can design successful exercise classes.

  1. Predictors of duloxetine adherence and persistence in patients with fibromyalgia

    Directory of Open Access Journals (Sweden)

    Cui Z

    2012-06-01

    Full Text Available Zhanglin Cui, Yang Zhao, Diego Novick, Douglas FariesEli Lilly and Company, Indianapolis, IN, USAObjectives: Adherence to medication for the treatment of fibromyalgia (FM is predictive of lower overall health-care costs, and thus a lower burden on both patients and providers. The objectives of this study were to examine the predictors of adherence to and persistence with duloxetine therapy among commercially insured FM patients, and to identify subgroups of patients with high duloxetine persistence and adherence.Study design: This cross-sectional, retrospective study analyzed medical and pharmacy records over 1 year for patients in the US aged 18–64 years with FM who initiated (no prior 90-day use duloxetine treatment in 2008.Methods: Adherence to duloxetine was measured by medication possession ratio (MPR, with high adherence defined as MPR ≥ 0.8. Persistence was defined as the duration of therapy from the index date to the earliest of: the ending date of the last prescription, the date of the first gap of >15 days between prescriptions, or the end of the study period (12 months. Demographic and clinical predictors of adherence were examined via multiple logistic regression (MLR, and subgroups of duloxetine-persistent and -adherent patients were identified using classification and regression trees (CART.Results: Among 4660 duloxetine patients, 33% achieved high adherence. Factors associated with high adherence from MLR included older age, North Central and Northeast regions, prior venlafaxine, pregabalin, selective serotonin reuptake inhibitor (SSRI, or other antidepressant use, or comorbid dyslipidemia or osteoarthritis (all P < 0.05. CART analysis revealed that patients with prior antidepressant use, aged ≥46, or prior osteoarthritis had higher MPR (all P < 0.05, and patients aged ≥45 with a history of SSRI, venlafaxine, or anticonvulsant use had longer duration of therapy (all P < 0.05.Conclusions: Patients with high adherence to and

  2. Medical adherence to topical corticosteroid preparations prescribed for psoriasis

    DEFF Research Database (Denmark)

    Svendsen, Mathias Tiedemann; Andersen, Flemming; Hansen, Jakob;

    2016-01-01

    OBJECTIVE: Topical corticosteroids and corticosteroid combinations are the principal treatments in psoriasis. The aim of this study was to investigate published literature dealing with medical adherence to topical corticosteroid or corticosteroid combinations in patients with psoriasis. MATERIALS...... health outcome in topical treatment of psoriasis, further studies should be conducted addressing determinants of nonadherence and test interventions to improve adherence. Validated measurements of medical nonadherence, prescription registers, or medication-weight are needed....

  3. Overactive bladder: strategies to ensure treatment compliance and adherence

    OpenAIRE

    Dhaliwal P; Wagg A

    2016-01-01

    Prabhpreet Dhaliwal, Adrian Wagg Department of Medicine, University of Alberta, Edmonton, Canada Abstract: Overactive bladder is a common, debilitating condition for many patients who may benefit from pharmacological management of their condition. However, adherence to medication in this condition is markedly worse than other chronic medical conditions. This review explores what is known about persistence and the factors which influence medication adherence for overactive bladder, those fac...

  4. Patient adherence to aromatase inhibitor treatment in the adjuvant setting

    OpenAIRE

    Verma, S.; Madarnas, Y.; Sehdev, S.; Martin, G; Bajcar, J.

    2011-01-01

    Improvements in adjuvant systemic therapy and detection of early disease have resulted in a decline of breast cancer death rates across all patient age groups in Canada. Non-adherence to adjuvant hormonal therapy in the setting of early breast cancer may significantly affect patient outcome. Factors associated with medication adherence are complex and may be patient-related, therapy-related, and health care provider–related. To date, there is a gap in the literature concerning a comprehensive...

  5. Medication adherence: the critical step towards better patient outcome

    Directory of Open Access Journals (Sweden)

    Anish Desai

    2014-10-01

    Full Text Available Medication adherence is defined as patient's adherence to take their medications as prescribed and continue to take the prescribed medication for stipulated time frame. Medication non-adherence is a growing concern to physicians, healthcare systems, and other stakeholders (e.g., payers and there is an increasing evidence of its prevalence and is associated with adverse clinical outcomes eventually resulting into higher costs of care. The cost of non-adherence has been estimated at $100 billion to $300 billion annually, including costs from avoidable hospitalizations, nursing home admissions, and premature deaths. Improving adherence to medication is critical to improve the quality of health care, to encourage better chronic care management, and promote better health outcomes. Reasons for non-adherence are multiple and complex. Studies have reported that poor adherence to drug dosage is due to patient perception that the disease is non-significant, adverse drug effects, lack of treatment effectiveness, and the patient's poor or incomplete knowledge of the disease and (cost. A multifactorial approach is required to tackle this complex problem as a single approach will be ineffective for all patients. The most effective intervention is to use a combination of approaches and address literacy, behavior, and organizational issues. There are challenges as well as opportunities in addressing the public health issue of medication adherence. Changing healthcare reforms, advances in digital health media, social media and modern technologies can now provide alternatives to tackle this issue. [Int J Basic Clin Pharmacol 2014; 3(5.000: 748-754

  6. Immunosuppressants and the renal transplant recipient: factors affecting adherence

    OpenAIRE

    Cairns, Jasmin

    2012-01-01

    In renal transplantation, immunosuppressants are prescribed to patients to prevent graft loss. Although the extent of adherence required for such treatment to prevent graft loss has not been determined, it is thought to be high. Despite this, research suggests adherence rates for renal transplant recipients to be only between 50% and 95%. Considering the impact of graft loss on the renal patient, the national healthcare budget and on the limited resource of donor organs, it is important to id...

  7. Objective Assessment of Adherence to Inhalers by COPD Patients.

    OpenAIRE

    Sulaiman, Imran; Cushen, Breda; Greene, Garrett; Seheult, Jansen; Seow, Dexter; Rawat, Fiona; MacHale, Elaine; Mokoka, Matshediso; Moran, Catherine Nora; Bhreathnach, Aoife Sartini; MacHale, Philippa; Tappuni, Shahed; Deering, Brenda; Jackson, Mandy; McCarthy, Hannah

    2016-01-01

    RATIONALE: Objective adherence to inhaled therapy by patients with COPD has not been reported. OBJECTIVES: The aim of this study was to objectively quantify adherence to preventer DiskusTM inhaler therapy by patients with COPD with an electronic audio recording device (INCATM). METHODS: This was a prospective observational study. On discharge from hospital patients were given a salmeterol/fluticasone inhaler with an INCATM device attached. Analysis of this audio quantified the frequency...

  8. Exploring self-management and adherence in haemophilia

    OpenAIRE

    Schrijvers, L.H.

    2015-01-01

    Throughout life, a patient with severe haemophilia is confronted with many treatment-related challenges. Insight into self-management and non-adherence could improve the quality of care for these patients. The aim of this thesis was to provide an overview of a series of studies on self-management and adherence to prophylaxis in haemophilia. Based on series of studies, aspects of treatment were explored: learning and performing self-infusion, achieving self-management skills in adolescence, ad...

  9. Treatment non-adherence in pseudo-refractory epilepsy.

    Science.gov (United States)

    Brodtkorb, Eylert; Samsonsen, Christian; Sund, Janne Kutschera; Bråthen, Geir; Helde, Grethe; Reimers, Arne

    2016-05-01

    Non-adherence to antiepileptic drug treatment strongly affects the outcome of epilepsy and is frequently clinically unrecognized. This review addresses current knowledge on medication-taking behavior in people with epilepsy, as well as the importance of tailoring interventions to the individual patterns of non-adherence. Non-adherence can be categorized as non-initiation, poor execution (accidental or intentional) or non-persistence and are related to clinical characteristics and health care barriers. All available methods to assess adherence are hampered by shortcomings. Self-reports are indirect and subjective. Pill-counts, electronic bottle-tops and pharmacy records are objective, but indirect measures of drug ingestion. Therapeutic drug monitoring is both direct and objective, but pharmacokinetic and diurnal variability must be taken into account. Young adults with generalized epilepsy may be particularly vulnerable to non-adherence. The drug burden in the form of polytherapy, multiple dosing and side effects are obvious obstacles. Poor understanding of the principles of prophylactic treatment as well as drug costs may be important in people with low socioeconomic status. Depression is also associated with low adherence. In people with multihandicaps, failed oral intake may be due to behavioral or physical problems, as well as insufficient education of the caregivers. Non-adherence often results in seizure breakthrough and hospital admissions, but the consequences may be more dramatic. It is the leading cause of status epilepticus in people with epilepsy, and the association with sudden death (SUDEP) is clear. The management of poor drug-taking behavior should be based on the identification of the specific causes in each individual and corresponding multiprofessional interventions. Non-adherence to antiepileptic drugs needs more clinical and scientific attention. PMID:26897547

  10. MONETARY EXPECTATIONS OF THE ROMANIAN EXECUTIVES REGARDING THE ADHERATION

    Directory of Open Access Journals (Sweden)

    Ramona DUMITRIU

    2006-01-01

    Full Text Available This paper explores the monetary expectations induced to the managers of Romanian firms by adheration. It is based on an investigation among twenty Romanian executives regarding the impact on adheration over monetary aspects: inflation, exchange rates and adoption of euro. We conclude that the results of the monetary policy in the last years made the executives confident that the Romanian authorities could maintain the monetary stability after theadheration.

  11. Family Social Status and Dietary Adherence of Patients with Phenylketonuria

    OpenAIRE

    Latif Gachkar; Gelareh Asadzadeh-Totonchi; Mohammadreza Alaei; Shirin Farivar

    2011-01-01

    Objective:There are several problems associated to the management of patients with phenylketonuria (PKU). Social status could be one of the affecting factors on dietary adherence in these patients. The aim of this study was to evaluate family social status and dietary adherence of PKU patients in Iranian population. Methods: In a cross-sectional study, we studied 105 Iranian PKU patients (born 1984 to 2010), treated and followed at Mofid Childrens Hospital, Tehran. Social status was defined b...

  12. Dietary Adherence During Weight Loss Predicts Weight Regain

    OpenAIRE

    Corral, Pedro Del; Bryan, David R.; Garvey, W. Timothy; Gower, Barbara A.; Gary R. Hunter

    2010-01-01

    This study examined the relationship between previous dietary adherence during a low-calorie diet weight loss intervention and subsequent weight change during a 2-year follow-up for weight maintenance. One hundred and sixteen healthy, recently weight reduced (lost ~12 kg, BMI 22–25 kg/m2) premenopausal women were studied. Dietary adherence was assessed by doubly labeled water (DLW) and body composition change. Comparisons were made between the upper and lower tertiles for previous dietary adh...

  13. relA Enhances the Adherence of Enteropathogenic Escherichia coli

    OpenAIRE

    Beny Spira; Gerson Moura Ferreira; Luiz Gustavo de Almeida

    2014-01-01

    Enteropathogenic Escherichia coli (EPEC) is a known causative agent of diarrhea in children. In the process of colonization of the small intestine, EPEC synthesizes two types of adhesins, the bundle-forming pilus (BFP) and intimin. The BFP pilus is an adhesin associated with the initial stages of adherence of EPEC to epithelial cells, while the outer membrane protein intimin carries out the intimate adherence that takes place at the third stage of infection. BFP is encoded by the bfp operon l...

  14. Deposition, characterization, and tribological applications of near-frictionless carbon films on glass and ceramic substrates

    International Nuclear Information System (INIS)

    As an element, carbon is rather unique and offers a range of rare opportunities for the design and fabrication of zero-, one-, two-, and three-dimensional nanostructured novel materials and coatings such as fullerenes, nanotubes, thin films, and free-standing nano-to-macroscale structures. Among these, carbon-based two-dimensional thin films (such as diamond and diamond-like carbon (DLC)) have attracted an overwhelming interest in recent years, mainly because of their exceptional physical, chemical, mechanical, electrical, and tribological properties. In particular, certain DLC films were found to provide extremely low friction and wear coefficients to sliding metallic and ceramic surfaces. Since the early 1990s, carbon has been used at Argonne National Laboratory to synthesize a class of novel DLC films that now provide friction and wear coefficients as low as 0.001 and 10-11-10-10 mm3 N-1 m-1, respectively, when tested in inert or vacuum test environments. Over the years, we have optimized these films and applied them successfully to all kinds of metallic and ceramic substrates and evaluated their friction and wear properties under a wide range of sliding conditions. In this paper, we will provide details of our recent work on the deposition, characterization, and tribological applications of near-frictionless carbon films on glass and ceramic substrates. We will also provide chemical and structural information about these films and describe the fundamental tribological mechanisms that control their unusual friction and wear behaviour

  15. Improved adhesion of photoresist to III-V substrates using PECVD carbon films

    Science.gov (United States)

    Mancini, David P.; Smith, Steven M.; Hooper, Andrew F.; Talin, A.; Chang, Daniel; Resnick, Douglas J.; Voight, Steven A.

    2002-07-01

    Amorphous PECVD carbon films have been investigated as a means to prepare III-V compound semiconductor substrates for improved photoresist adhesion. Results show that significant improvements in adhesive durability of patterned photoresist occurred for carbon primed GaAs and InGaAs wafers used in conjunction with both i-line and DUV lithography processes. These carbon layers, were 50-100 Angstrom in thickness, and varied in composition and morphology from a nitrogen-doped, diamond-like material (DLC), to a more hydrogen rich, polymer-like material (PLC). Adhesion durability tests performed in baths of ammonium hydroxide (NH4OH) and hydrochloric acid (HCl) in general showed superior performance compared to non-primed substrates. The sole exception was a failure of PLC priming on GaAs wafers used with a DUV anti-reflective coating. This same system, however, was shown to work extremely well when a DLC coating was substituted. Characterization of PLC and DLC films included use of AES, XPS, FTIR, AFM, and contact angle analysis. Results indicate that carbon films passivate III-V oxides, creating a stable, hydrophobic surface. This factor is proposed as a key reason for the improved resistance to aggressive aqueous environments. AFM results show that carbon films are extremely smooth and actually decrease surface roughness, indicating that mechanical adhesion is unlikely.

  16. Household Contact Screening Adherence among Tuberculosis Patients in Northern Ethiopia.

    Directory of Open Access Journals (Sweden)

    Gebremedhin Berhe Gebregergs

    Full Text Available Household contacts of active tuberculosis cases are at high risk of getting tuberculosis disease. Tuberculosis detection rate among contacts of household members is high. Hence, this study investigated household contact screening adherence and associated factors among tuberculosis patients in Amhara region, Ethiopia.A cross-sectional study was conducted from April 10 - June 30, 2013 in five urban districts of Amhara region, where 418 patients receiving treatment at tuberculosis clinic were interviewed. All patients were interviewed using structured and pre-tested questionnaire. Bringing at least one household contact to TB clinic was regarded as adherent to household contacts screening. Bivariate and multiple logistic regressions were used to investigate association.The overall adherence to household contact screening in Amhara region was 33.7%. Adherence was higher among Muslims than Christians. Adherence was high if patient took health education from Health Care Worker [AOR: 3.22, 95% CI: 1.88 to 5.51] and 2.17 times higher if patient had sufficient knowledge on tuberculosis [AOR: 2.17, 95% CI: 1.29 to 3.67] during interview. Relationship with contact was a significant [AOR: 0.4, 95% CI: 0.2 to 0.9] social related factor.One third of tuberculosis patients adhered to household contact screening in health facilities during their treatment course. Promoting knowledge of tuberculosis in the community and continuous health education to tuberculosis patients are recommended.

  17. Bipolar disorder and medication: adherence, patients' knowledge and serum monitoring of lithium carbonate Trastorno bipolar y medicamentos: adhesión, conocimiento de los pacientes y monitorización sérica del carbonato de litio Transtorno bipolar e medicamentos: adesão, conhecimento dos pacientes e monitorização sérica do carbonato de lítio

    Directory of Open Access Journals (Sweden)

    Camila de Souza

    2013-04-01

    Full Text Available OBJECTIVES: this study featured patients with affective bipolar disorder who were making use of lithium and received care at an outpatient care center located in a country town in the state of Sao Paulo in 2009; it assessed the adherence and knowledge of these patients in relation to the medication prescribed to them and verified the proportion of blood tests performed per year in the service, for each individual, to measure lithium levels in the blood. METHOD: descriptive study with quantitative approach, involving 36 participants. Structured interviews and review of medical records were used for data collection and descriptive statistics for data analysis. RESULTS: difficulties in reporting the dosage of the medication prescribed and a high rate of non-adherence were identified among the participants. None of the participants in the study was submitted to two tests a year to measure lithium levels in the blood, which is the minimum proportion of tests recommended by the literature for maintenance treatment using lithium carbonate. CONCLUSION: this study highlights the critical factors for the promotion of patients' safety in monitoring lithium drug therapy. OBJETIVOS: este estudio caracterizó pacientes con trastorno afectivo bipolar, tratadas con litio, atendidos en el año de 2009 en un servicio de ambulatorio del interior del estado de Sao Paulo, en Brasil; evaluó la adhesión y conocimiento de los mismos sobre medicamentos prescritos y verificó la proporción de litemias/año realizadas, en el servicio, para cada individuo. MÉTODO: se trata de estudio descriptivo, con abordaje cuantitativo, del cual participaron 36 personas. Fueron utilizadas entrevistas estructuradas y revisión de fichas para recolección de datos y estadística descriptiva para análisis de los mismos. RESULTADOS: entre los participantes, fueron identificadas dificultades en relatar la dosis de los fármacos prescritos y una alta tasa de no adhesión. En ning

  18. Comparison of adherent and non-adherent staphylococci in the induction of polymorphonuclear leukocyte activation in vitro

    DEFF Research Database (Denmark)

    Riber, U; Espersen, F; Kharazmi, A

    1995-01-01

    The ability to consume complement and activate neutrophils was investigated for staphylococci adherent to silicone surfaces and non-adherent staphylococci. Staphylococcus epidermidis strain ATCC 14990 and Staphylococcus aureus strain E 2371 were used in this study. The bacteria were allowed...... at 37 degrees C. The bacteria consumed complement to approximately the same extent when adherent to the catheter segments, but more slowly in comparison with planktonic bacteria. When planktonic bacteria were compared, complement was consumed more quickly by S. epidermidis than by S. aureus. Measuring...... the induction of chemiluminescence by planktonic bacteria, S. epidermidis induced a lower response than S. aureus, while when adherent to the catheter segments the bacteria induced similar responses. These responses were only 15 to 20% of those induced by planktonic bacteria and only slightly higher than...

  19. Alcohol use, antiretroviral therapy adherence, and preferences regarding an alcohol-focused adherence intervention in patients with human immunodeficiency virus

    Directory of Open Access Journals (Sweden)

    Kekwaletswe CT

    2014-03-01

    Full Text Available Connie T Kekwaletswe,1 Neo K Morojele1,21Alcohol and Drug Abuse Research Unit, Medical Research Council, Pretoria, 2School of Public Health, University of the Witwatersrand, Johannesburg, South AfricaBackground: The primary objectives of this study were to determine the association between alcohol and antiretroviral therapy (ART adherence and the perceived appropriateness and acceptability of elements of an adherence counseling program with a focus on alcohol-related ART nonadherence among a sample of ART recipients in human immunodeficiency virus (HIV clinics in Tshwane, South Africa.Methods: We conducted a cross-sectional study with purposive sampling. The sample comprised 304 male and female ART recipients at two President's Emergency Plan For AIDS Relief-supported HIV clinics. Using an interview schedule, we assessed patients' alcohol use (Alcohol Use Disorders Identification Test, other drug use, level of adherence to ART, and reasons for missing ART doses (AIDS Clinical Trials Group adherence instrument. Additionally, patients’ views were solicited on: the likely effectiveness of potential facilitators; the preferred quantity, duration, format, and setting of the sessions; the usefulness of having family members/friends attend sessions along with the patient; and potential skill sets to be imparted.Results: About half of the male drinkers’ and three quarters of the female drinkers’ Alcohol Use Disorders Identification Test scores were suggestive of hazardous or harmful drinking. Average self-reported ART adherence was 89.7%. There was a significant association between level of alcohol use and degree of ART adherence. Overall, participants perceived two clinic-based sessions, each of one hour’s duration, in a group format, and facilitated by a peer or adherence counselor, as most appropriate and acceptable. Participants also had a favorable attitude towards family and friends accompanying them to the sessions. They also favored an

  20. Impact of an exercise program on adherence and fitness indicators.

    Science.gov (United States)

    Carpenter, Roger; Gilleland, Diana

    2016-05-01

    Adherence to exercise is one of the most problematic health behaviors. This pilot study describes the impact of an exercise program on adherence to exercise and fitness indicators for overweight and obese adults enrolled in an insurance reimbursed exercise plan. Chart reviews were conducted retrospectively in a convenience sample of 77 subjects from a human performance lab (HPL) at a large southern university. Charts from 2004 to 2009 were reviewed for health history, fitness indicators (fitness level, weight, BMI, hip/waist ratio, % body fat, BP, HR, cholesterol), and adherence (number of exercise sessions/month). Exercise supervision was operationalized in two phases over 12 months: Phase I (3 months supervised exercise) and Phase II (9 months unsupervised exercise). Fifty-eight participants completed Phase I, and 8 completed Phase II. Six-nine percent of those completing Phase I visited the gym at least 8 times/month with significant (α=.05) improvement in all fitness indicators. Those visiting fitness level, weight, BMI, and % body fat. Twenty-four subjects continued into Phase II, with only eight completing Phase II. Of those eight, only one subject visited the HPL at least 8 times/month. Health history data including co-morbidities, symptoms, habits, perceived tension, job stress, and fitness level were not associated with adherence. Symptoms of swollen, stiff, painful joints, and swollen ankles and legs were associated with decreased adherence to exercise. Supervised exercise was positively related to adherence and improved fitness indicators. Adults with joint symptoms may require more support. Based on these pilot data, designing a study with a larger sample and the inclusion of barriers and facilitators for adherence to self-directed exercise would allow additional analysis. Innovative interventions are needed that mimic the supervised environment, shifting responsibility for the exercise plan from the supervisor to those exercising.