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Innsbruck, Austria

Klauser F.,University of Innsbruck | Steinmuller-Nethl D.,BeSt coating GmbH | Kaindl R.,University of Innsbruck | Bertel E.,University of Innsbruck | Memmel N.,University of Innsbruck
Chemical Vapor Deposition | Year: 2010

Amulti-wavelength, visible-Raman study of structurally different nanocrystalline diamond (NCD) films grown by means of hotfilament (HF)CVD is presented. The Raman spectra are qualitatively and quantitatively analyzed by applying current interpretation models. It is demonstrated that specific properties of the diamond phase as well as the grain boundaries can be extracted from the Raman spectr A. Hydrogenated amorphous carbon is detected in the films grain boundaries and characterized regarding its hydrogen content, optical gap, and sp3 content. The characteristic trans-polyacetylene-like signals are observed, and the behavior of the corresponding peaks studied in detail. The results are correlated with film properties such as grain size, morphology, roughness, and refractive index, as determined by atomic force microscopy (AFM), X-ray diffraction (XRD), and ellipsometry. Source

Ghodbane S.,CNRS Neel Institute | Ghodbane S.,BeSt coating GmbH | Omnes F.,CNRS Neel Institute | Agnes C.,CNRS Neel Institute
Diamond and Related Materials | Year: 2010

In this work we use cathodoluminescence (CL) at liquid helium temperature to investigate the boron incorporation in {111}-homoepitaxial diamond films, grown outside the visible plasma ball by the Microwave plasma-assisted chemical vapor deposition (MPCVD) technique. The boron concentration of this set of films covers the whole possible doping range divided into four parts: Low doping (5 × 1016 < [B] < 1.5 × 1019 cm- 3), high doping (1.5 × 1019 < [B] < 3 × 1020 cm- 3), heavy doping (3 × 1020 < [B] < 2 × 1021 cm- 3), and phase separation range ([B] > 2 × 1021 cm- 3). The phase separation occurs for very high boron concentrations, between the diamond phase (sp3 carbon) and the other components of the layer, namely sp2 carbon and boron. A part of them is accumulated outside the diamond lattice. This detailed cathodoluminescence investigation of {111}-homoepitaxial diamond films has led to determining the doping range of the films and following the evolution of their crystalline quality when the boron concentration increases. In addition, a comparison between {111} and {100} films in the same doping ranges has been undertaken. © 2009 Elsevier B.V. All rights reserved. Source

Ghodbane S.,CNRS Neel Institute | Ghodbane S.,BeSt coating GmbH | Ballutaud D.,French National Center for Scientific Research | Omnes F.,CNRS Neel Institute | Agnes C.,CNRS Neel Institute
Diamond and Related Materials | Year: 2010

In this work, we have used X-ray photoelectron spectroscopy (XPS) to investigate the nature of surface adsorbed species and their sensitivity to the boron concentration [B] in two sets of as-grown diamond films: homoepitaxial {111} and polycrystalline. These sets cover each one at least three of the four doping ranges: low doping (5 × 1016 < [B] < 1.5 × 1019 cm- 3), high doping (1.5 × 1019 < [B] < 3 × 1020 cm- 3), heavy doping (3 × 1020 < [B] < 2 × 1021 cm- 3), and phase separation ([B] > 2 × 1021 cm- 3). The results are compared to those we have previously obtained on {100} homoepitaxial films in the same doping ranges. A detailed description of both the nature and the relative concentrations of the main surface chemical species on every set of films is reported. Besides the usual CHx bonds on the diamond surface, the following oxygen-related groups: Ether (C-O-C), hydroxyl (C-OH, only on polycrystalline films), carbonyl (> C=O) and carboxyl (HO-C=O) have been found on the surface of grown diamond films, upon spontaneous oxidation under air (no oxidation treatment has been applied). The evolution of each surface chemical group according to the boron concentration in the films is. © 2010 Elsevier B.V. All rights reserved. Source

Kloss F.R.,Innsbruck Medical University | Singh S.,Austrian Academy of Sciences | Hachl O.,Innsbruck Medical University | Rentenberger J.,Innsbruck Medical University | And 9 more authors.
Head and Neck | Year: 2013

Background Irradiation results in impaired bone healing. Thus, osteosynthesis procedures are afflicted with increased failure rates. To improve osseointegration bone morphogenetic protein-2 (BMP-2) immobilized on nanocrystalline diamond (NCD)-coated implant surfaces might be 1 solution. Methods By 4 weeks after irradiation of pig's mandible with a dose of 60 Gy a fracture was accomplished. Osteosynthesis was performed either with titanium osteosynthesis screws or NCD-coated screws with immobilized BMP-2. Nonirradiated animals served as control. After 1, 2, 4, and 8 weeks screws were evaluated histologically. Bone biopsies were gained to extract mesenchymal stem or precursor cells (MSCs). Results MSCs after irradiation demonstrated a behavior comparable to that of unirradiated cells. Consequently, immobilized BMP-2 resulted in an initial increased bone contact ratio (p =.014) but demonstrated no sustainable effect compared with osseointegration in nonirradiated bone (p =.08). Conclusion Immobilized BMP-2 demonstrates an osteoinductive effect in irradiated bone. MSCs as effector cells possess protective mechanisms to overcome the destructive effect of irradiation. © 2012 Wiley Periodicals, Inc. Source

Steinmueller-Nethl D.,BeSt coating GmbH | Roy M.,Defence Metallurgical Research Laboratory | Franek F.,Vienna University of Technology
International Journal of Refractory Metals and Hard Materials | Year: 2010

Diamond films are well known for their outstanding properties such as high hardness, possible low coefficient of friction, high thermal conductivity, excellent biocompatibility and electrical insulation. Diamond films with nanocrystalline grains (grain sizes between 3 and 15 nm) offer further advantages of low compressive stress, low surface roughness, and high amount of surface atoms in relation to volume leading to enhanced surface properties. In view of these, the present investigation is undertaken to explore the possibility of using nanocrystalline diamond (NCD) films in advanced automotive equipment. Accordingly NCD-films have been deposited using a modified hot-filament technique. Tribological behaviour of these films has been evaluated by means of a reciprocating model tribometer with different lubricant qualities. The worn surfaces were examined using scanning electron microscopy (SEM) and 3D white light confocal microscopy. The results show the influences of coating qualities and test conditions on the tribological response. Comparable friction coefficient can be found with high treated and low treated lubricants. These films exhibited negligible wear for the range of load tested. © 2009 Elsevier Ltd. All rights reserved. Source

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