Symposium : U
Carbon- or Nitrogen-Containing Nanostructured Thin Films
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| Carbon- or nitrogen-based polymer nanocomposites : C. Donnet, S. Tamulevicius | ||
| 08:30 | Polymer/CNTs nanocomposites prepared with help of plasmachemical processes Authors : Lenka Zajíčková, Marek Eliáš, Vilma Buršíková Affiliations : Central European Institute of Technology and Department of Physical Electronics, Masaryk University, Brno, Czech Republic Resume : The key moment of preparation of polymer nanocomposites filled by carbon nanotubes (CNTs) is their homogeneous dispersion in the polymer matrix and covalent bonding between inert surface of CNTs and polymer chains. Both can be ensured by a functionalization of CNTs. We have performed plasma functionalization of a commercially available CNTs powder in low pressure rf capacitive discharges and atmospheric pressure cold plasma jet. The plasma jet was applied in distilled water or peroxide solutions with dispersed CNTs. Attachment of new functional groups to CNTs was investigated with X-ray photoelectron and infrared spectroscopy. We have investigated relation between plasma conditions, detection of functional groups and properties of polyurethane (PU) composites reinforced by CNTs. The polyurethane was prepared from polyol, isocyanate and solvent thinner. CNTs were ultrasonicated in polyol and solvent thinner with small addition of an antistatic agent added to improve their dispersion in polymer blend. Mechanical properties of dried polymer composites were studied by depth sensing indentation. Different maximum loads were applied and the measurement on each sample and at each load was repeated at various places. The mechanical quantities were obtained from the measurements at such load at which the indentation depth was much less than one tenth of the film thickness, i.e. the influence of the substrate was negligible. | 9 1 |
| 09:00 | Advanced methods in Ti/hydrocarbon plasma polymer nanocomposites study Authors : Martin Svec (1), Stanislav Novak (1), Rudolf Hrach (1, 2) Affiliations : (1) Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske mladeze 8, 400 96 Usti nad Labem, Czech Republic (2) Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 180 00 Prague 8, Czech Republic Resume : Composite films are very interesting materials for their extraordinary mechanical, electrical and optical properties. These properties can be strongly influenced by geometry of inclusions embedded into a matrix. We are dealing with structured Ti/hydrocarbon plasma polymer nanocomposite films deposited at a glancing angle by magnetron sputtering in our contribution.
A correlation between a slant of inclusions and a resistivity of the structure was experimentally observed and measured. We study this phenomenon with a self-made computer experiment. The model consists of generation of the structures with columnar inclusions, their morphological and resistivity analysis. The generation of the structures is done with the Monte Carlo method, while the morphological analysis uses the theory of percolation methods (the modified burning method) to determine an ohmic conductivity network, so-called infinite cluster. The electrical properties are studied with the network analysis methods.
Our model corresponds with the experimental measurements and shows how the slant of inclusions influences the electrical resistivity. It is shown that the electrical resistivity increases with the angle of deposition, i.e. with the angle of inclusion slants. These observations are analysed and discussed. | 9 2 |
| 09:20 | Investigations of poly(L-lactide)/ TiO2 nanocomposite thin films for optical protective thin films Authors : Wei Wei Wang, Frédéric Reisdorffer, Yi Dan, Thien Phap Nguyen Affiliations : Wei Wei Wang, Frédéric Reisdorffer, Thien Phap Nguyen-Institut des Matériaux Jean Rouxel, 2 rue de la Houssinière, BP32229, 44322 Nantes, France; Yi Dan,State Key Laboratory of Polymer Materials Engineering of China, Polymer Research Institute of Sichuan University, Chengdu 610065, P. R. China Resume : Poly(L-lactide) (PLLA) is a biodegradable polymer which has numerous potentials uses, including applications in medical, textile and packaging industry. Its degradation in natural conditions is an asset but can hardly be controlled in pure form. Titanium dioxide (TiO2) nanoparticles have high photocatalytic properties and are used as pure green protective coatings as well as UV protection layers. Using nanocomposites made of PLLA and TiO2, the advantages of both components are expected to be preserved and offer interesting materials with controllable degradability under UV irradiation.
In this work, we have investigated poly(L-lactide)/TiO2 hybrid nanocomposite thin films synthesized in situ on the surface of TiO2 nanoparticles through ring-opening polymerization of the polymer. The electronic structure of the composites was analyzed by Infrared, UV-vis absorption and Raman spectroscopy and their composition was determined by thermogravimetric analysis. These characteristics were compared to those of pure PLLA and were found to be strongly dependent of the polymer weight and the nature of the oxide (anatase or rutile). On the other hand, from scanning electron microscopy images and X-ray diffraction patterns of hybrid thin films, it was observed that the chains are aggregated and crystallized around the TiO2 particles to form a radial morphology. The effects of TiO2 on the degradation of the nanocomposites under UV irradiation as a function of time have shown that the process could be controlled by adjusting the TiO2 concentration, making possible its use in time flexible protective coating technology. | 9 3 |
| 09:40 | Coffee break | |
| New deposition and characterization methods I : C. Donnet, J. Emmerlich | ||
| 10:20 | Nanostructured polyfluorene thin films: enhanced photoluminescence and stability by incorporation of AZO nanoparticles Authors : Cuong Ton-That 1, Dorian Alden 1, Matthew R. Phillips 1, Y. Dan 2, Thien-Phap Nguyen 3 Affiliations : 1 School of Physics and Advanced Materials, University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia; 2 Polymer Research Institute of Sichuan University, 24 South Section1, Yihuan Road Chengdu 610065, China; 3 Institut des Matériaux Jean Rouxel, 2, rue de la Houssinière, 44322 Nantes, France Resume : Luminescence properties of nanocomposite thin films consisting of Al-doped ZnO (AZO, 35 nm) nanoparticles in polyfluorene were investigated by photoluminescence (PL) using 325 nm excitation of a He-Cd laser. Pristine polyfluorene exhibits a green emission peaked at 545 nm (FWHM 43 nm). Incorporation of AZO nanoparticles enhances the luminescence, with a maximum enhancement factor of 4 achieved at 10 wt% AZO, while the peak position and FWHM are unaffected. As the nanoparticles are strongly excited by the above AZO bandgap excitation, the data suggest efficient electron transfer from nanoparticles, leading to enhanced radiative recombination at the polymer interface. No evidence of changes in spectral shape or peak energy of the PL emission was observed, indicating that the effective conjugation length is not significantly affected by AZO nanoparticles. To examine the stability of the composite films, the decay of the green emission was measured with a constant power density of 3.2 W/cm2 in air and vacuum. Both pristine and AZO-doped polyfluorene films exhibit decreasing PL intensity with irradiation time, but the decay occurs more slowly in vacuum, pointing to photo-oxidation mechanism. Under identical irradiation conditions, the decay rate decreases with increasing AZO concentration up to 10 wt%. The results illustrate that AZO nanoparticles can act a photo-oxidation inhibitor, and that the nanocomposite films are promising materials for efficient, stable optical devices. | 1 1 |
| 10:40 | A new route of InP in optoelectronic devices? Authors : A.M. Goncalves*1, C. Njel1, C. Mathieu1, D. Aureau1, N. Mezailles2, J.L. Pelouard3, A. Etcheberry1 Affiliations : 1- Institut Lavoisier de Versailles ILV - UMR- CNRS 8180 (http://www.ilv.uvsq.fr) UVSQ, 45, Avenue des Etats-Unis 78035 Versailles Cedex- France. *Fax/Tel: 33 (0) 1 39 25 44 19/18 - E-mail: goncalves@chimie.uvsq.fr 2- Laboratoire H?ro?ments et Coordination ?ole Polytechnique, UMR- CNRS 7653 (http://www.dcph.polytechnique.fr) Route de Saclay -91128 Palaiseau cedex – France 3- Laboratoire de Photonique et Nanostructure-LPN CNRS UPR 20- (http://www.lpn.cnrs.fr )Site Alcatel de Marcoussis, route de Nozay, 21460 – Marcoussis France Resume : In comparison to silicon, InP gets better performances in optoelectronic applications. However, the spontaneous surface oxidation of InP makes very difficult its integration in attractive devices. Recently, we succeed in performing a monolayer film on InP in liquid ammonia1-2. This non aqueous solvent allows electrochemical anodic treatments excluding the formation of oxide surface. This protective film, involving a sub-mC.cm-2 spent charge, can be photoassisted (or not) using voltammetry or galvanostatic mode1-2. InP is entirely recovered by a monolayer of phosphazene like structure ( H2N P=NH ) avoiding the air ageing of the surface. The presence of amino groups provides a unique opportunity for further functionalization, as exemplified by the first chemically controlled coordination of Pt(II) centers. These results open the way for investigation of the reactivity of this film towards organic, inorganic fragments and metal nanoparticles. To provide an industrial process in NH3 Liq., we succeed in performing this film, using an electroless process, which does not require any electrochemical cell and voltage source. The unexpected chemical stability and robustness of the protective film could be compared with hydrogenated silicon.
1 A-M. Gon?ves at al. Chem. Mat. 22, 3114 (2010).
2 A-M. Goncalves at al. Electrochem. Soc. 1101 1326 (2011) | 1 2 |
| 11:00 | High density nanodiamond monolayer obtained by an electrophoretic process Authors : Schmidlin Loïc(1), Pichot Vincent(1), Josset Sébastien(1), Comet Marc(1), Rabu Pierre(2), Spitzer Denis(1) Affiliations : (1) NS3E « Nanomatériaux pour les Systèmes Sous Sollicitations Extrêmes » UMR CNRS-ISL no 3208, French-German Research Institute of Saint-Louis, 5 rue du général Cassagnou 68301 Saint-Louis, France (2) Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504 CNRS- Université de Strasbourg, 23 rue du Loess, Boîte Postale 43 67034 Strasbourg Cedex 02, France Resume : Electrophoretic deposition is an efficient method to deposit colloidal particles on an electrode by using an electrical field. This technique has already been used for the deposition of nanoparticles [1] or nanodiamonds [2] and was here applied to detonation ultra-nanocrystalline diamonds (D-UNCD). To obtain ultrathin D UNCD deposit, the use of suspension containing individual nanodiamonds is crucial.
The D-UNCD used in this study were synthesized and purified at the ISL [3]. The D-UNCD particles surface is mainly covered by carboxylic groups [4] resulting in a negative surface charge when suspended in water. A mechanical treatment was applied to the D-UNCD to obtain suspension containing separated nanodiamonds with an average size of 3 5 nm. An electrical field was applied to this colloidal suspension to deposit the D-UNCD on a Highly Oriented Pyrolitic Graphite electrode. The obtained deposits were characterised by Atomic Force Microscopy (AFM). The deposits topography is 5 nm, corresponding to a monolayer deposition of D-UNCD. The deposits density obtained with this technique is estimated to be over 1012 particles/cm2. Due to the proximity of the nanodiamonds particles, an AFM tip with a radius of 1 nm wasn’t able to discern them. To our knowledge such a density has never been obtained before. Such deposit is suitable for sensing applications or as seeding for diamond CVD growth. | 1 3 |
| 11:20 | Hyperthermal ion effects on the morphology of carbon-transition metal nanocomposite thin films Authors : G. Abrasonis (1), M. Krause(1,2), A. Mücklich (1), S. Gemming (2), M. M. M. Bilek (3) Affiliations : (1)Helmholtz-Zentrum Dresden-Rossendorf, PF-510119, 01314 Dresden, Germany. (2)Institut für Festkörperphysik, Technische Universität Dresden, 01062 Dresden, Germany. (3) School of Physics, University of Sydney, New South Wales 2006, Australia Resume : Nanostructures influence materials properties dramatically due to size, shape and interface effects. Thus the control over the structure at the nanoscale is a key issue in nanomaterials science. The interaction of hyperthermal ions with solids is confined to some nanometers. It can be e.g. used to control the morphology evolution during multiphase film deposition, since ion induced displacements occur in a thin surface layer of the growing film where they increase the atomic mobility for the phase separation. In this contribution a comparison of the growth-structure relationship of carbon-transition metal (Ni, Cu) nanocomposite films grown ion beam assisted deposition and pulsed filtered cathodic arc is reported. These type of nanocomposites are relevant in the context of sensing, fusion, electrochemistry, tribology, information storage and spintronics. The formation of elongated nickel nanoparticles is strongly promoted by temperature and the ion beam assistance. Moreover, the metal nanocolumns no longer align with the advancing surface, as in the case without ion assistance, but with the incoming ions. For both deposition techniques, a window of conditions is established where the ion assistance leads to the formation of regular nanopatterns. As the dominating driving force for the pattern formation is of physical origin, this approach might be applicable to other immiscible systems. | 1 4 |
| 11:40 | Carbon containing nanostructured thin films obtained by TVA technology in different configurations for specific applications Authors : Rodica VLADOIU1, Victor CIUPINA1, Mirela CONTULOV1, Virginia DINCA1, Aurelia MANDES1, Cristian Petrica LUNGU2 Affiliations : 1Department of Plasma Physics, Ovidius University, Mamaia 124, Constanta, 900527, Romania 2National Institute of Lasers, Plasma and Radiation Physics, Atomistilor 111, P.O. Box MG-36, Magurele-Bucharest, Romania Resume : Thermionic Vacuum Arc (TVA) technology is one of the best versatile methods offering product developers the chance to create entirely new properties through the controlled manufacture and structuring of materials, and driving innovation in many sectors of industry.
This method uses an electron beam emitted by an externally heated cathode accelerated by a high anodic voltage. The electron beam can evaporate the anode materials as neutral pure particles and facilitate their deposition on the substrate when the electron energy and current intensity are not too high. By increasing up to a certain value the anode potential, the evaporation rate raises enough to allow a bright discharge to be ignited in the evaporated pure material. The discharge is hereby maintained even when the current is as low as a few hundreds mA. Also, TVA method allows the simultaneous deposition of different materials on the same substrate, providing the possibility of designing multi-component thin films.
Nanometer-scaled thin films deposition as metals, alloys, ceramics, DLC and refractory metals such as W, Mo, Ta, Nb, Re, B but also nanocomposites as C-Me with low roughness, good smoothness and low friction coefficient could be synthesized in different TVA’s electrodes configurations.
The aim of this paper is to correlate the symmetry of the electrodes, relative position of the anode versus cathode, and the types of anodes in order to have specific applications of carbon containing desired nanomaterials (thin films, multilayers, nanocomposite or alloys). | 1 5 |
| 12:00 | Multifunctional sol-gel-derived carbon black-silica/titania films Authors : Thomas Hübert, Muhammad Shabir, Marion Männ, Sebastian Chruscicki Affiliations : BAM Federal Institute for Materials Research and Testing, 12203 Berlin, Germany Resume : Sol-gel technology enables to prepare new nano composite films in a cost effective way by hydrolysis of alkoxides and dispersion of nanoparticles in a liquid precursor. We demonstrate how electrical properties and optical properties can be tailored by composition and synthesis procedure.
Alcoholic precursor solutions were prepared by acidic hydrolysis of TEOS/MTEOS or TIP in which nano scaled carbon black was suspended. Films of up to 5 µm thickness were precipitated by dip and spin coating on polished quartz wafer, dried and heat treated up to 300 °C. The film formation process was monitored by DTA/TG. Film structure was investigated by SEM and EDX showing agglomerated 30 nm carbon black particles in oxide matrix.
Electrical resistivity of nano composites decreases with increasing carbon content over ten decades from 10 GΩcm to 0.1 Ωcm announcing a percolation threshold at 0.5.
The optical properties of films carbon black containing in silica, titania or mixed matrix were investigated in the UV-vis range. The optical constants n and k extracted from ellipsometric measurements varies from 0.95 to 2.0 and 0.1 to 0.85 in the range of 200 to 1700 nm. Reflectivity measurements give values in range of 3.2 to 13 %. Experimental data were compared with results predicted by theoretical models for two-phase media. | 1 6 |
| 12:20 | Lunch break | |
| a-C films : W.-D. Münz, T. Polcar | ||
| 14:00 | Pulsed laser deposition of carbon-based coatings: highlights, limitations and new trends with ultrafast laser pulses Authors : C. Donnet, F. Garrelie, A-S. Loir Affiliations : University Jean Monnet & University de Lyon, Laboratoire Hubert Curien, UMR 5516 Resume : Carbon-based films are very attractive and valuable because of their exclusive capacity to present a combination of unique properties which can be tailored over a wide range. Pulsed Laser Deposition (PLD) is widely used for the synthesis of various thin films, in particular, near room temperature, pure Diamond-Like Carbon (DLC) films with a predominance of sp3 hybridization (ta-C), and nanostructured carbon-based films (a-C:X), thanks to an accurate control of the concentration of the incorporated foreign elements. PLD may be performed using ultra short laser pulses, responsible for an increase of the kinetic energy of the ejected particles up to a few keV. The characteristics of the plasma are a well-suited signature of the physics of laser-matter interaction, the plasma plume creation and expansion. Original film properties may be achieved, including lower stress, higher adhesion, low friction and wear, and designed electrical properties. In the femtosecond regime, clusters of a few tens nanometers of diameter are generally generated during the ablation of most materials. These particles may be incorporated into the carbonaceous network by co-ablation of carbon and an other material, leading to the formation of nanostructured films, opening the way to wide applications towards functional materials. The talk will review some significant results published by us and others, highlighting relationships between deposition process, characterization and properties of carbon based films deposited by ultrafast laser ablation. Some comparison between femtosecond and nanosecond PLD will be also reviewed. Recent studies on the control of the film growth and femtosecond PLD mechanisms will be reported. Emphasis on the capability of the existing sources to elaborate high quality materials will be questioned in terms of energy per pulse, time width, repetition rates but also in the need for further source developments and beam shaping improvements. One challenge will be to control more accurately the carbon hybridization and the nanostructure of such films. | 3 1 |
| 14:30 | Highly ionized carbon fluxes for the growth of diamond-like carbon films using magnetron sputtering Authors : Asim Aijaz, Kostas Sarakinos, Daniel Lundin, Ulf Helmersson Affiliations : Plasma and Coatings Physics Division, IFM-Materials Physics, Linköping University, SE-58183, Linköping, Sweden Resume : High power impulse magnetron sputtering (HiPIMS) has been successful in providing highly ionized deposition fluxes for most common metals (Cu, Al, Ti). However, it is challenged when non-metals such as carbon is considered. Highly ionized carbon fluxes (up to 100%) are essential for the synthesis of diamond-like carbon and tetrahedral amorphous carbon. Previous reports have shown that C /C ratio in HiPIMS does not exceed 5% [1]. In this work, we introduce a new strategy to increase the degree of ionized carbon in magnetron sputtering [2]. It is based on promoting electron impact ionization of carbon by increasing the electron temperature when using Ne in a HiPIMS discharge. The characterization of the Ne-based process using a Langmuir probe and mass spectrometry shows that it provides an increase in the electron temperature resulting in an order of magnitude decrease in the mean ionization length of the sputtered C as compared to conventional Ar-HiPIMS discharges. The C ion energy distribution functions exhibit the presence of an energetic C ion population and a substantial increase in the total C ion flux. The increased C ionization facilitates the growth of sp3 rich carbon films with mass densities reaching as high as approx. 2.8 g/cm3.
Key words: DLC, ta-C, carbon ionization, HiPIMS.
References
[1] B.M. DeKoven, et al., SVC, 46th Annual Technical Conference Proceedings, (2003) 158.
[2] A. Aijaz, et al, Diamond and Related Materials, DOI: 10.1016/j.diamond.2011.12.043. | 3 2 |
| 14:50 | The role of inert gas in CNx and a-C thin film deposition by HIPIMS and DCMS Authors : S. Schmidt1*, G. Greczynski1, Zs. Czigany2, L. Hultman1 Affiliations : 1 Thin Film Physics Div., Department of Physics (IFM), Linkoping University, SE-581 83, Sweden; 2 Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Konkoly Thege Miklos ut 29-33, H-1121 Budapest, Hungary Resume : Neon, argon, and krypton were used to map the role of inert gases in sputtering of pure carbon and reactively sputtered carbon-nitride (CNx) compounds in high power pulsed magnetron sputtering (HiPIMS/HPPMS) and DCMS modes. Thin solid films were synthesized in an industrial deposition chamber from a pure graphite target. In the case of a-C films the deposition took place in a pure Ne, Ar and Kr atmosphere, whereas CNx thin films were grown in an Ne, Ar or Kr / N2 atmosphere with a constant N2/inert gas flow ratio of 0.16. Throughout the deposition the pressure was kept constant at 400 mPa and the average target power was similar for both deposition techniques. The resulting thin films were characterized regarding their bonding and microstructure as well as film properties by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, transmission electron microscopy (TEM), contact angle measurements, and nanoindentation.
The peak target current during HIPIMS processing was found to decrease with increasing inert gas mass. This was mirrored in the microstructure of the thin films, as an ordering towards fullerene-like films occurred for inert gas masses higher than that of Ne. Carbon and carbon nitride films deposited in Ne atmosphere were found to be fully amorphous. However, the effect of the inert gas on the microstructure was not as distinct when N2, as reactive gas, was introduced into the deposition chamber. XPS results revealed a dependency on the sputtering mode as the sp3/sp2 ratio increased for films produced by DCMS in Kr or in Ne atmosphere. An opposite trend was found for C thin films deposited by HiPIMS. The results gained by TEM and XPS are discussed and related to the current understanding on the structural evolution of a-C and CNx thin films. | 3 3 |
| 15:10 | Microstructural evolution in hard CNx coatings deposited by industrial-scale DC magnetron sputtering Authors : S. Louring, N.D. Madsen, A.N. Berthelsen, B.H. Christensen, K.P. Almtoft, L.P. Nielsen, J. B?ger Affiliations : Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University, Ny Munkegade, Bldg. 1520, DK-8000 Aarhus C, Denmark; Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University, Ny Munkegade, Bldg. 1520, DK-8000 Aarhus C, Denmark; Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University, Ny Munkegade, Bldg. 1520, DK-8000 Aarhus C, Denmark; Danish Technological Institute, Tribology Centre, Teknologiparken, Kongsvang All?9, DK-8000 Aarhus C, Denmark; Danish Technological Institute, Tribology Centre, Teknologiparken, Kongsvang All?9, DK-8000 Aarhus C, Denmark; Danish Technological Institute, Tribology Centre, Teknologiparken, Kongsvang All?9, DK-8000 Aarhus C, Denmark; Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University, Ny Munkegade, Bldg. 1520, DK-8000 Aarhus C, Denmark Resume : Carbon nitride (CNx) coatings were deposited by reactive DC magnetron sputtering with an industrial-scale deposition system, where the reactive gas N2 was used in combination with graphite targets. A systematic variation of the substrate bias voltage and the deposition temperature was performed to study the mechanical and microstructural properties of the various coatings. The mechanical properties – hardness and elastic modulus – were extracted from nanoindentation data, and the residual film stress was determined from substrate bending. At deposition temperatures below ~200°C, the films were amorphous. Increasingly negative substrate bias voltages resulted in an increased compressive stress and an improved hardness, which may be explained by an increased amount of sp3 C-C bonds in the amorphous network. Moreover, when the deposition temperature was increased at constant substrate bias voltage, the compressive stress was more than doubled, reaching a value of 4.5 GPa at a temperature of ~390°C. Based on a highly elastic nanoindentation response, XPS analyses of the N 1s transition and Raman spectroscopy, the increased compressive stress at elevated temperatures is suggested to be due to a structural transition from an essentially amorphous coating towards a structure containing bent and cross-linked graphite-like sheets. TEM analyses are in progress. | 3 4 |
| 15:30 | Coffee break | |
| Poster session : C. Mitterer | ||
| 16:00 | The role of mechanical and bio-corrosive influence on microstructure damage of multilayer TiN/Ti/a-C:H coatings Authors : Łukasz Major Affiliations : Institute of Metallurgy and Materials Science Polish Academy of Sciences, 25 Reymonta street, PL-30-059 Krakow, Poland, nmlmajor@imim-pan.krakow.pl; Resume : The effect of mechanical and bio- corrosive influence on microstructure of multilayered titanium nitride- TiN/ titanium- Ti/ amorphous carbon- a-C:H (TiN/Ti/a-C:H) coatings has been analyzed. Coatings were deposited using Pulsed Laser Deposition technique (PLD) with different number of layers and phases ratio. They were subjected to mechanical (ball-on-disc) wear test, as well as bio- corrosive (in body fluids) test. The microstructure of coatings was characterized before and after tests. Their microstructure was characterized using TECNAI G2 F20 (200kV) FEG transmission electron microscope (TEM). The chemical and phase composition were examined by Energy Dispersive X-Ray Spectroscopy (EDS), electron diffraction patterns and high resolution technique (HRTEM). Thin foils were prepared directly from the wear track by focused ion beam method (FIB) using QUANTA 200 3D DualBeam. The multilayer coatings exhibited strongly dislocated microstructure in TiN layers, while a-C:H were amorphous. After mechanical test the multilayer TiN/Ti/a-C:H coating was strongly deformed. Ceramic TiN and a-C:H layers showed brittle cracking, while thin metallic Ti layers (presented at each interface) deformed plastically. Plastic deformation was propagating in 45 degree to crystalline growth direction. The wear of crystalline TiN layers caused cracks along {111} crystallographic planes. The presence of metallic phase played an important role in the cracking resistance properties and an energetic cost of propagating cracks increase. The multilayered system has an influence into the increase
of corrosion resistance properties. | 13 1 |
| 16:00 | Study of electrochemical performances for heavy metal detection of different amorphous-carbon films deposited by femtosecond pulsed laser ablation Authors : B. Khadro a, A. Sikora b, A.-S. Loir b, A. Errachid a, F. Garrelie b, C. Donnet b, N. Jaffrezic-Renault a Affiliations : a Institut des Sciences Analytiques, University Claude Bernard Lyon1, 69622 Villeurbanne, France b Laboratoire Hubert Curien, University Jean Monnet, 42000 Saint-Etienne, France Resume : Pure and doped diamond-like carbon (DLC, B-DLC and N-DLC) thin films have been synthesized on silicon substrates by femtosecond pulsed laser deposition. The amorphous carbon materials consisting mainly of sp3 bonds, have been deposited at room temperature by ablating graphite targets with an amplified Ti:sapphire laser of 800 nm wavelength and a pulse duration of 150 fs in high vacuum conditions. Doping with boron (2-8 atomic %) has been performed by ablating alternatively graphite and boron targets whereas doping with nitrogen has been obtained by ablating graphite in a nitrogen atmosphere (1.10-3 to 5.10-1 mbar). The structural and morphological analyses have been correlated with the electrochemical performances. In this study, the amorphous-carbon films were used as working electrodes to detect trace of heavy metals namely, Pb2+, Cd2+ , Ni2+ and Hg2+, by using square wave anodic stripping voltammetry (SWASV) technique. The effect of the boron doping on the electrochemical behavior has been shown. The a-C:B(8%) / Si3N4 electrode gives the most sensitive detection. The four metals were detected simultaneously with a detection limit of 1 µg.L−1 or 2 µg.L−1 and a dynamic range from 1 or 2 to 25 µg.L−1 for every metal. The different sensitivities obtained were 20.0, 6.2, 1.2 and 6.6 µA/ppb or µA.µg−1.L for Pb2+, Cd2+, Ni2+ and Hg2+, respectively. DLC film has been demonstrated to be a viable alternate electrode for ASV measurements. | 13 2 |
| 16:00 | Influence of Al content on the phase formation, growth stress and mechanical properties of TiZrAlN coatings Authors : I. A. Saladukhin1,2, A. Michel1, G. Abadias1, V. V. Uglov2, G. N. Tolmachova3, S. N. Dub4 Affiliations : 1. Institut P’ , Université de Poitiers-CNRS-ENSMA, 86962 Chasseneuil-Futoroscope, FRANCE; 2 Belarusian State University, 220030 Minsk, BELARUS; 3 Kharkov Institute of Physics and Technology, 61108, Kharkov, UKRAINE; 4 Institute for Superhard Materials, NAS of Ukraine, 04074 Kiev, UKRAINE Resume : Transition metal nitride based coatings have shown excellent mechanical properties, oxidation resistance and thermal stability. In order to improve further the functional properties of these materials, the current research strategy aims at designing new ternary or multinary systems, by means of alloying different metal or non-metal elements.
The present study is focused on the quaternary TiZrAlN system with the aim of investigating the correlation between phase formation, stress and mechanical properties upon incorporation of Al in the cubic (Ti,Zr)N lattice. (Ti,Zr)1-xAlxN coatings, with x up to 0.36, were grown by reactive dc (Ti, Zr targets) and rf (Al target) magnetron sputtering under Ar+N2 plasma discharges. The stress was measured in situ during growth from the change in the wafer curvature using a multi-beam optical stress sensor. The structure and phase formation were examined using XRD and TEM, while Nanoindentation was used to determine the hardness H and elastic modulus E.
A clear correlation is found between growth regimes, stress, structural and hardness evolutions as a function of the Al content. Three distinct regions are revealed: i) for x<0.06, a (111) columnar structure and large compressive stress (up to - 4 GPa), for 0.06< x <0.14, nanocrystalline grains with (002) preferred orientation and increasing H/E ratio iii) 0.14< x< 0.36, XRD-amorphous nanocomposites with low residual stress (about -1 GPa) and decreasing hardness. | 13 3 |
| 16:00 | Influence of the yttrium content on the oxidation mechanism of ZrN films Authors : David Pilloud, Jean-François Pierson Affiliations : Institut Jean Lamour, CP2S, Université de Lorraine, 54042 Nancy, France Resume : Zirconium nitride films have potential application as protective coatings due to their high hardness, high thermal stability as well as their good wear and corrosion resistances. Despite many works have been performed on the functional properties of ZrN films, the effects of a third element on the oxidation process are more scarcely investigated.
In this study, 3 µm-thick films of Zr-Y-N were elaborated by pulsed-DC sputtering from metallic zirconium targets with different yttrium compositions (0, 8 and 16 at. %) in a reactive mixture of Ar/N2.
The structure of the films was determined by XRD. The ratio Y/Zr was assessed by EDS. Hardness was measured by nanoindentation tester. The morphological features of the films were characterized by SEM. Zirconium nitride films with different yttrium contents were oxidized in air during 2 hours up to 700°C and characterised in order to emphasis the role of yttrium in the stabilization of the subsequent zirconia layer forming during the oxidation step. For this purpose, the oxidized films have been analysed ex-situ both by XRD and Raman spectroscopy and thanks to a Linkam® cell, in-situ FTIR measurements were done to investigate the first stages occurring before the crystallization. | 13 4 |
| 16:00 | Probing the structure and the hardness of titanium/carbon nanocomposite coatings deposited by hybrid PVD/PECVD process Authors : A.A. El Mel1, E. Gautron1, F. Christien1, B. Angleraud1, A. Granier1, P. Souček2, P. Vašina2, V. Buršikova2, M. Takashima3, N. Ohtake3, H. Akasaka4, T. Suzuki5, and P.Y. Tessier1 Affiliations : 1Université de Nantes, CNRS, Institut des Matériaux Jean Rouxel, UMR 6502, 2 rue de la Houssinière B.P. 32229 - 44322 Nantes cedex 3 – France 2Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlarska 2, CZ-61137, Brno, Czech Republic 3Department of Mechanical Sciences and Engineering, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro-ku, Tokyo 152-8552, Japan 4Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan 5Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan Resume : Titanium/carbon nanocomposite hard coatings, which consist of TiC nanoparticles buried in an amorphous carbon matrix, have been prepared by a hybrid plasma process combining magnetron sputtering of a titanium target and plasma enhanced chemical vapor deposition using methane as a source for amorphous carbon. The chemical composition of the bulk has been determined by Rutherford backscattered spectroscopy, and wavelength dispersive X-ray spectroscopy. The surface composition has been evaluated by X-ray photoelectron spectroscopy before and after argon ion erosion. Bulk and surface analysis techniques did not provide the same results. The origin of these differences is discussed in details. Moreover, the structure of the coatings has been extensively probed by transmission electron microscopy, which has shown that when increasing the carbon content within the coating the size of the TiC nanoparticles shrinks. We further demonstrate that this structural evolution has a direct impact on the hardness of the coatings which gets reduced when the carbon content increases. | 13 5 |
| 16:00 | Reduction of AlN nano-foil adhesion to Si substrate by low-flux of beta-irradiation Authors : A. A. Dmitrievskiy 1), Yu. I. Golovin 1), A. R. Lovtsov 1), N. Yu. Efremova 1), V. V. Korenkov 1), A. V. Shuklinov 1), M. Badylevich 2, 3) Affiliations : 1) Tambov state university named after G.R. Derzhavin, 392000 Tambov, Russia 2) Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium 3) Present affiliation: Light and Lighting Laboratory, Catholic University College Gent, Gebroeders Desmetstraat 1, B-9000 Gent, Belgium Resume : The goal of the work was to investigate the influence of low-flux (I = 1,2×10^5 cm^-2s^-1) beta-irradiations on characteristics of AlN amorphous thin film exfoliation from a silicon substrate. For that purpose the samples with as-grown and additionally irradiated 100 nm thick AlN amorphous films were scratched by Berkovich pyramid with linearly increasing load P (from 0 to 2 mN) using Nanoindenter G200. It was revealed that the AlN layer on the irradiated samples starts to exfoliate from the silicon substrate at smaller force applied to indenter. It was shown that the effect of this force reduction takes place only with the scratch depth exceeding a thickness of an amorphous film of aluminum nitride (~ 100 nanometers), and can attain 30-40 % with scratch depth 150-180 nm. The obtained results of beta irradiations influence on adhesive properties of silicon have potential to be used in different wafer-bonding technologies or fabrication of nano-foils.
This work was supported by the Special Federal Program “Scientific and Pedagogical Personnel of innovative Russia” for 2009–2013 (Project No. P892). | 13 6 |
| 16:00 | Thermal stability and physical-mechanical properties of hard and superhard Zr-Ti-Si-N coatings Authors : A.D. Pogrebnjak1, O.V. Sobol2, V.M. Beresnev2, D.A. Kolesnikov4, F.F. Komarov5, V.S. Baidak1, A.P. Shypylenko1, B.R. Zhollybekov6. Affiliations : 1. Sumy State University, Department of Nanoelectronic, 2, R.-Korsakova,40007, Sumy, Ukraine e-mail: alexp@i.ua 2. Kharkov Technical University, Kharkov, Ukraine 3. Kharkov National University, Kharkov, Ukraine 4. Belgorod State University, Belgorod, Russia 5. Belarus State University, Minsk, Belarus 6. Karakalpak State University, Karakalpak, Usbekistan Resume : Nanostructured coatings were obtained by vacuum-arc deposition with HF discharge (VAD) applied to the substrate. One-piece cathode of such composition: Ti = 8.8 wt.%, Si = 12 wt.%, Zr = 64.2 wt.%, was used for depositing. To make the comparison the coatings of Ti-Si-N were used target: Ti = 32.1 wt.%, Si = 3,7 wt.%. The molecular nitrogen was used as a reactive gas. The thickness of all obtained coatings was 2 m. The arc current was about 100 A, the nitrogen pressure PN = 0.3 Pa, HF potential – 200 V. For providing the analysis such methods were used: RBS, EDS, Dual-beam SEM (Quanta 200 3D) and XRD analysis for determining the phase composition.
Additional tribological tests were carried out using the high-temperature machine “High temperature Tribometer”, CSM Instruments, in the air at temperatures: 20C, 300С and 500С by the "ball-disk" scheme. As a rider a ball of 6 mm diameter, made of certified material Al2O3 was used. Coatings were deposited on disks, made of 45 steel (HRC = 55) with 50 mm diameter, and 5 mm thickness.
X-ray diffraction data indicated the presence of oxides (ZrO2, TiO2, TiN, Si3N4, (ZrTi)N) on the coating surface after high temperature tests. The size of nitride phase was very small and amounts to 4.5-5.0 nm.
The coatings demonstrate high hardness 44 GPa, and elastic modulus E = 480 GPa. The coating Ti23-Zr2,5-Si3.0 hardness after high temperature tests at 300ºC and 500ºC increased to 56 GPa. | 13 7 |
| 16:00 | Arc plasma deposition of multilayered a-C:H/TiC and a-C:/ZrC Authors : A.Vladescu, C.N.Zoita, M.Balaceanu, V.Braic, A.Kiss, M.Braic Affiliations : National Institute for Optoelectronics, 409 Atomistilor Str., Magurele-Bucharest, Romania Resume : To solve the problems related to high internal stress and poor adhesion of amorphous carbon films, preparation of multilayers comprising alternating layers made of carbon and a transition metal carbide could be a promising approach. In the work reported here, a comparative investigation of the main characteristics of a-C:H/TiC and a-C:H/ZrC multilayers was performed. The depositions were carried on Si and steel substrates by the cathodic arc technique in a CH4 reactive atmosphere, using two cathodes made of C and Ti (or Zr). The multilayer structures were analyzed for composition, microstructure, morphology, modulation periodicity, mechanical and tribological properties by using XPS, XRD, X-ray reflectivity, AFM, residual stress, microhardness and adhesion measurements, and tribological tests.
The characteristics of the coatings were found to mainly depend on CH4 flow rate and bilayer period. As compared to the a-C:H single layer coatings, the multilayers exhibited reduced stress levels and improved adhesion on steel substrate.
Hardness values in the range 28 – 35 GPa were measured. Low friction coefficients (0.1 – 0.15) and high wear resistance (wear rate < 10-7mm3N-1m-1) were determined in sliding tests in air, so that the a-C:H/TiC and a-C:H/ZrC multilayers are expected to perform well in real tribological applications. | 13 8 |
| 16:00 | Deposition and characterization of multi-principal-element (CuSiTiYZr)C thin films Authors : M. Balaceanu1, V. Braic1, C.N. Zoita1, A. Vladescu1, I. Pana1,2, I. Stefanescu1,3, M. Braic1 Affiliations : 1National Institute for Optoelectronics, 409 Atomistilor Str., Magurele-Bucharest, Romania 2 Faculty of Physics, University of Bucharest, 405 Atomistilor Str., Magurele-Bucharest, Romania 3 University Politehnica of Bucharest, 313 Sp.Independentei, Bucharest, Romania Resume : In recent years, multi-principal-element alloys, commonly termed as “high-entropy alloys” (HEAs) have been increasingly investigated due to their excellent mechanical properties. Based on HEA’s concept, thin films with at least 5 principal elements in almost equal atomic ratios, have been found to form nanocrystalline solid solution or amorphous phases, resulting in superior mechanical characteristics and high wear and corrosion resistance.
The purpose of the present study was to investigate the characteristics of a novel type of a HEA-based film, namely (CuSiTiYZr)C. The film constituents were carefully selected taking into account different criteria: atomic radius, mixing enthalpy and valence electron concentration. The films were deposited in Si and C45 substrates through co-sputtering of pure Cu, Si, Ti, Y and Zr targets in an Ar+CH4 reactive atmosphere. The influence of Carbon concentration on film properties was investigated. The films were analyzed for elemental and phase composition, crystalline structure, mechanical characteristics and tribological performance.
Depending on the process parameters, amorphous or nanocrystalline structures (solid-solution or binary (ternary) phases) were formed. Fine grained, smooth surface morphologies and dense cross-sectional microstructures were observed by AFM and SEM. Film hardness values in excess of 30 GPa and friction coefficients bellow 0.2 were measured for films prepared under proper deposition conditions. | 13 9 |
| 16:00 | Functional Zr-containing carbonitride coatings Authors : V. Braic, M. Balaceanu, A. Vladescu, C. Vitelaru, M. Braic Affiliations : National Institute for Optoelectronics, 409 Atomistilor Str., Magurele-Bucharest, Romania Resume : The paper reports on hard coatings containing Zr, as main or additional element, obtained by reactive magnetron sputtering and cathodic arc methods. The deposition systems used metallic mono-element or alloyed targets, operating in a mixture CH4 and N2, at a pressure of about 0.5 Pa. Coatings were characterized by: AES, EDX or GDOES (elemental composition), XPS (chemical binding state), XRD (phase composition, grain size), microhardness tester, surface profilometry (thickness and stress), AFM (surface roughness), scratch test (adhesion), and pin-on-disc tribometry.
The incorporation of small amounts of different metals (Ti, Al, Hf, Nb) in the structure of the ZrCN basic system, as well as the addition of Zr as alloying element to different carbonitride compounds (TiCN, TiAlCN, TiNbCN), resulted in the improvement of hardness, adhesion and tribological performance, no matter the deposition method used.
All the coatings exhibited a fcc structure, with an (111) preferred orientation. For all coatings, the presence of Zr as main or additional element, resulted in a hardness enhancement, which was more pronounced for the stoichiometric coatings, as compared to the overstoichiometric ones. The hardness increase may be explained by lattice deformation, solid solution strengthening, defect hardening mechanisms and favourable valence electron concentration. Some representative applications of different coatings are presented. | 13 10 |
| 16:00 | Study of CrZrCN nanocomposite hard coatings Authors : M.Balaceanu, A.Vladescu, A.Kiss, V.Braic, C.N.Zoita, C. Vitelaru, M.Braic Affiliations : National Institute for Optoelectronics, 409 Atomistilor Str., Magurele-Bucharest, Romania Resume : In the last decade, multicomponent coatings have attracted a lot of attention because of their excellent properties such as high hardness, low friction coefficient, high wear resistance, low residual stress level and good adhesion to steel substrates. Among them, the coatings containing small amounts of different elements (Al, V, Nb, W, Mo, Y, Si and B) as additions to a binary or ternary compound have been found to exhibit improved mechanical and tribological properties as compared to the base systems without alloying elements.
The purpose of the present study was to investigate the characteristics of a quaternary carbonitride coating, namely CrZrCN, in which Zr is alloying elements. The coatings, with thicknesses of 4-5 μm, were deposited on Si and C45 steel substrates by the cathodic arc method in a mixture of Ar, N2 and CH4 gases.
The coatings were comparatively investigated for elemental and phase composition, texture, hardness, corrosion resistance, friction and wear performance. Film characteristics were assessed in comparison to CrN, CrC and CrCN reference coatings.
The CrZrCN coatings were found to consist of nanostructured fcc solid solutions, with an (111) preferred orientation, and a crystallite size as low as 2-3 nm. It was shown that Zr incorporation in CrCN basic structure resulted in a hardness enhancement (with 4 – 8 GPa) and an improvement of corrosion resistance, friction and wear behaviour. | 13 11 |
| 16:00 | Nanocomposite tungsten-carbon film formation by terawatt laser system irradiation Authors : C.P. Lungu1, C. Porosnicu1, I. Jepu1, A. M. Lungu1, P. Chiru1, A. Marcu1, C. Luculescu1, R. Banici1, D. Ursescu1, R. Dabu1, I. D. Feraru2, C. E. A. Grigorescu2, G. E. Iacobescu3, M. Osiac3, J. Kovač4,5, V. Nemanič4 Affiliations : 1National Institute for Laser, Plasma and Radiation Physics, 077125 Bucharest, Romania 2National Institute R&D for Optoelectronics INOE 2000, 077125 Bucharest, Romania 3Department of Physics, University of Craiova, Craiova, 200585, Romania 4“Jožef Stefan” Institute (JSI), Jamova 39, 1000 Ljubljana, Slovenia 5Center of Excellence for Polymer Materials and Technologies, Tehnološki park 24, 1000 Ljubljana, Slovenia Resume : Tungsten and carbon films with the thickness of 200 +/- 20 nm and 2500 +/- 250 nm respectively were deposited sequentially on fine grain graphite substrates using the original Thermionic Vacuum Arc method developed at the National Institute for Laser, Plasma and Radiation Physics. The method uses circular heated cathodes emitting high intensity electron beams capable to melt refractory materials such as W and C. The samples were irradiated using a terawatt laser system (Tewalas), 20-30 x 10– 15 s pulse duration, 400 - 450 mJ pulse energy. The plasma plume produced by the laser pulses was investigated using a VUV spectrometer. The spectra were recorded in the 10-22 nm range from successive pulses in the same sample locations. After laser irradiation, optical imaging, scanning electron microscopy and XPS studies revealed nanostructured CW formation at the C-W interface. The Raman scattering measurements inferred the characteristic D and G modes of carbon in all samples while the specific peak at 1330 cm-1 corresponding to diamond was observed too. Nanohardness measurements using a nanoindenter gave values of 20+/- 5 GPa, opening the possibility of using such materials as protective coating on a wide range of mechanical components, including the first wall of a fusion reactor.
Acknowledgement
This work was supported from the Ministry of Education, Research and Sports of Romania, through contract PN-II-ID-PCE-2011-3-0522. | 13 12 |
| 16:00 | Tribology of sputtered selenium-based solid lubricants alloyed with carbon Authors : F. Gustavsson(1), T. Polcar (2,3), S. Jacobson (1), A. Cavaleiro (4) Affiliations : (1) The Ångström Tribomaterials Group, Dep. of Engineering Sciences, Uppsala University , Box 534, 75121 Uppsala, Sweden, (2) Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical university in Prague, Technická 2, Prague 6, Czech Republic, (3) National Centre for Advanced Tribology at Southampton (nCATS), School of Engineering Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, UK (4) SEG-CEMUC- Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, P-3030 788 Coimbra, Portugal Resume : Solid lubricants based on transition metal dichalcogenides are important candidates to applications where liquid lubrication is not wanted or possible. They are widely used but also limited to vacuum applications due to their sensitivity to humidity, which strongly deteriorate their tribological properties. Excellent frictional properties of such films are attributed to easy inter or intra-crystalline slip between adjacent molecular layers. Sputtered MoS2 and WS2 thin films have been thoroughly investigated and applied. However, sputtering often leads to sulfur to metal ratio much lower than 2 due to re-sputtering effect affecting the much lighter sulfur than W or Mo. When sulfur is replaced by selenium, the Se/metal ratio is expected to be close to ideal stoichiometry. Furthermore, selenium-based films are less sensitive to humidity than sulfide-based ones. To improve hardness, coating density and load-bearing capacity, transition metal dichalcogenides are often doped or alloyed.
In this study, Mo- and W diselenide coatings co-sputtered with carbon are investigated with respect to their tribological properties in various environments, such as different contact pressure and environment (argon, nitrogen, dry and humid air) The coatings structure and chemical bonding have been evaluated by X-ray photoelectron microscopy (XPS), Raman spectroscopy, X-ray diffraction and transmission electron spectroscopy (TEM), mechanical properties have been addressed by scratch tests and nanoindentation. Special attention has been paid to tribological tests using a pin-on-disc setup and particularly to analysis of the worn surfaces (both the coating and the counterpart).
XPS, TEM, Raman analysis and scanning electron microscopy equipped with Energy-dispersive X-ray spectroscopy have been applied in localized spots in the wear track giving exact information about tribolayer composition and phase orientation. The results show decrease of the friction and wear with higher load at high humidity (RH 60%). Noteworthy is that the wear was at the same very low level in both Ar and Humid air for MoSe-C but the friction was five times higher in humid air. | 13 13 |
| 16:00 | Morphology reconstruction and mechanical stress evolution in annealed and oxidized a-SiC:H films Authors : A.V. Vasin*, Y.Y. Gomeniuk*, A.V. Rusavsky*, A.N. Nazarov*, V.S. Lysenko*, P.M. Lytvyn*, C. Nouveau**, S.P. Starik** Affiliations : *Lashkaryov Institute of Semiconductor Physics, Kiev, 03028 Ukraine; **CER Arts et Métiers ParisTech, Rue Porte de Paris, F-71250, Cluny, France; ***Bakul Institute of Superhard Materials, 2 Avtzavodskaya str., Kiev, 04074 Ukraine Resume : Amorphous carbon rich a-SiC:H films were deposited on silicon substrates by RF-magnetron sputtering of SiC target in argon/methane gas mixture. Density of the films was varied by varying RF-discharge power. After the deposition the samples were thermally treated in argon or oxygen environment. The main subject of the study was investigation of the effect of thermal annealing and oxidation treatment of amorphous SiC network on mechanical stresses evolution and its correlation with structural reconstruction. Local nanoscale examination of surface morphology and chemical composition distribution were examined by atom force microscopy and scanning electron microscopy equipped with Auger electron scanning system. Mechanical stresses were calculated using Stoeny equation. As deposited films exhibited compressive stress that was partially relaxed after annealing in pure argon. It was found that annealing in oxygen leads to morphology reconstruction accompanied by drastic evolution of mechanical stresses from compressive to tensile depending on the annealing conditions and density of the starting material. It is suggested that selective area and precisely controllable thermal treatment in oxygen can be used for engineering of the mechanical stresses in a-SiC:H thin films. | 13 14 |
| 16:00 | Deposition of the SiOx containing diamond like nanocomposite films on glass: mechanical properties and adhesion Authors : Š. Meškinis, A. Vasiliauskas, V. Kopustinskas, R. Gudaitis, S. Tamulevičius Affiliations : Institute of Materials Science of Kaunas University of Technology Savanorių 271, 50131 Kaunas, Lithuania Resume : Diamond-like carbon (DLC) is an amorphous composite material consisting of the sp2 bonded carbon clusters embedded into the sp3 bonded carbon (diamond like) matrix. These films received considerable interest due to their unique properties. These properties can be additionally controlled by incorporating into the growing films different chemical elements or compounds. Particularly SiOx containing DLC films (other name - diamond like nanocomposite films) received considerable interest due to the substantially reduced stress level, increased optical transparency, high hardness, low friction, high hydrophobicity. In most cases SiOx containing DLC films deposited on silicon and steel substrates were investigated. Deposition of DLC films on different glass substrates is important for numerous applications. However, peculiarities of the adhesion of SiOx containing DLC films with glass remain unclear. While adhesion of the “conventional” undoped DLC films with glass is worse than adhesion with the most often in such a studies used substrate silicon. Therefore different substrate treatment techniques are considered.
In present study SiOx containing diamond like nanocomposite films were deposited by anode layer ion source. Float glass was used as a substrate. Microhardness and elastic modulus of the deposited films was measured. Adhesion of the films was evaluated by scratch test. Effects of the deposition conditions and substrate preparation methods were considered. | 13 15 |
| 16:00 | The investigation of Si-C matrix-based metal-containing nanocomposite materials by SPM methods Authors : Ekaterina Kanaeva, Michail Malinkovich Affiliations : National University of Science and Technology "MISIS" Resume : Si-C matrix-based metal-containing nanocomposite materials are perspective materials with properties, comparable with properties of diamond-like-carbon films. Si-C films are very promising materials for various technical applications, because of their reception properties, allowing to implant in nanoparticles of metal during growth in an amorphous layer. These films can be dielectrics (with 10-4 Оhm∙сm) or good conductors (1011Ohm∙cm) by a variation concentration of metal, its type, growth kinetics and other parametres of a precipitation process.
It was earlier revealed that the electroconductivity has the anisotropy of metal-containing Si-C films. In order to find out the reasons of that, the investigation of distribution on the surface of chrome, tantalium and platinum nanoparticles by SPM methods was done. Applicability of SPM methods is proved by that the AFM method can show only roughness of the surface while STM method allows to define not only a relief, but also potential distribution on a surface.
AFM surface images have casual roughnesses with the average size about 0,2 nanometers without the expressed relief. STM - images show the ordered distribution of electronic density and represent formations of the hemispherical or extended form with the sizes from 5 to 200 nanometers - depending on type of metal and its containing in the material.
The ordered distribution of potential on a surface can be caused the ordered distribution of particles of metal during film synthesis. Such structure in distribution of particles can be the reason of electroconductivity anisotropy. | 13 16 |
| 16:00 | The influence of carbon source on the properties of carbon-vanadium composite films obtained by magnetron sputtering and ion implantation technique Authors : E. Grigore, C. Ruset, C. Luculescu Affiliations : National Institute for Lasers, Plasma and Radiation Physics Resume : A large research effort is dedicated nowadays to a relative new class of materials consisting of a metallic/carbide phase embedded in a carbon matrix. They have a large potential application area from tribology to plasma facing materials for fusion devices.
The integration of a metallic element within a carbon matrix improves the wear resistance, the adhesion of the coating to the substrate, preserves a low friction coefficient and reduces the internal stress.
The aim of this paper is to comparatively investigate the influence of carbon source type on the structure and the properties of carbon-vanadium composite films. The films were obtained by a DC magnetron system assisted by a high voltage pulse discharge applied to the substrate. As source of carbon a complex graphite/vanadium target and a hydrocarbon gas have been used. High voltage pulses of 20µs with amplitude of 30kV and a frequency of 25 Hz were applied on the substrate simultaneous with DC bias. As a result of the ion bombardment, a compact nano-structure with a microhardness up to 4,000 HV0.025 and a thickness of about 10 µm has been obtained.
The chemical and structural analyses were performed by EDX, XPS, GDOES, XRD, and SEM while microhardness and scratch test measurements were used to assess the mechanical properties. Tribological characteristics were evaluated in terms of friction coefficient and wear rate by pin-on-disk tests taking as a reference an uncoated high speed steel sample. | 13 17 |
| 16:00 | Tribological performance of Ti-DLC films deposited with magnetron sputtering using Taguchi method Authors : Kaan Kurucu, Özlem Baran, İhsan Efeoglu,Yaşar Totik Affiliations : Atatürk University, Faculty of Engineering,Mechanical Engineering Department,Erzurum,Turkey;Erzincan University, Faculty of Engineering,Mechanical Engineering Department,Erzincan,Turkey;Atatürk University, Faculty of Engineering,Mechanical Engineering Department,Erzurum,Turkey;Atatürk University, Faculty of Engineering,Mechanical Engineering Department,Erzurum,Turkey Resume : Diamond-like carbon (DLC) films ensure low friction and high wear resistance to sliding-contact interfaces, therefore, these films are increasingly attracting interest for a wide range of tribological applications. In this work, Ti-DLC composite films were deposited on M2 steel and glass substrates at the different target currents and working pressures with closed field unbalanced magnetron sputtering (CFUBMS) using Taguchi L4 (32) method. The structural properties of Ti-DLC composite films were investigated by XRD and SEM. The mechanical properties of these films were determined with microhardness tester. The friction and wear properties of films were analyzed at different test athmospheres (humid air, distillated water and synthetic oil) by using pin-on-disc. Consequently, using of the different coating parameters improved mechanical and tribological properties of Ti-DLC composite films.
Key Words: DLC, wear resistance, Ti, CFUBMS, Taguchi method | 13 18 |
| 16:00 | Characterization of laser clads by laser-induced breakdown spectroscopy technique Authors : V. Piñon, J.M. Amado, M.J. Tobar, M. Mateo, A. Yañez, G. Nicolas Affiliations : Universidad de A Coruña, Laboratorio de Aplicaciones Industriales del Láser, Campus de Ferrol, Spain Resume : Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. So this work was devoted on one hand, to produce laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder on stainless steel substrates of austenitic type (AISI 304) and on the other hand, to employ the laser-induced breakdown spectroscopy (LIBS) technique to chemically characterize these clad layers. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks, on large areas with overlapped tracks and on multiple layers. In this last case, a material with concentration gradient has been produced applying different proportions of WC particles through the coating. The results achieved by LIBS technique allowed us to determine the chemical composition of these coatings and was particularly interesting for multiple layers with different concentrations where the LIBS rasters performed on cross-sections allowed to discriminate the thicknesses of the different layers. Moreover the LIBS signals were correlated with the hardness measurements on these materials showing their dependence. | 13 19 |
| 16:00 | Effect of surface defects on the tribology of WSC-Cr self-lubricant coatings Authors : J.V. Pimentel, F. Gustavsson, T. Polcar, A. Cavaleiro Affiliations : Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6, Czech Republic; Ångström Tribomaterials Group, Uppsala University; Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6, Czech Republic SEG-CEMUC - Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, P-3030 788 Coimbra, Portugal Resume : Transition metal dichalcogenides (TMD) belong to one of the most developed class of materials for solid lubrication. However, one of the main drawbacks of most of the self-lubricating coatings is their low load-bearing capacity, particularly in terrestrial atmospheres. In previous works, alloying TMD thin films based on tungsten disulfide with non-metallic interstitial elements, such as carbon or nitrogen, has been studied in order to improve tribological performance in different environments. Excellent results were reached having the deposited coatings hardness, in some cases, more than one order of magnitude higher than single W-S films.
In this work, W-S-C films were alloyed with Cr by-co sputtering chromium and composite WS2-C targets. Besides the usual physical, chemical and mechanical characterization, including the evaluation of the chemical composition, the structure, the morphology, the hardness and the cohesion/adhesion, special attention was paid to the friction and wear analyses of the film deposited on deliberately damaged surface. The substrates were steel polished disk with different type of scratches produced by micromachining.
To analyse the sliding process, in-situ techniques were applied, such us optical and Raman monitoring of the wear track. The surfaces in the contact were then analysed by scanning electron microscopy (SEM) and 3D profilometer.
The results clearly showed that the friction coefficient of W-S-C/Cr coating on damaged surfaces was in many cases even lower than that of polished substrate. It was demonstrated that scratches were filled out by transferred coating material identified as WS2. Thus, the surface damage acted as solid lubricant reservoirs. | 13 20 |
| 16:00 | DLC(H) doped with Zr coated on biomedical Ti based substrates Authors : A. Escudeiro (1), T. Polcar (2,3), A. Cavaleiro (1) Affiliations : (1) SEG-CEMUC – Department of Mechanical Engineering, University of Coimbra, 3030-788 Coimbra, Portugal (2) National Centre for Advanced Tribology (nCATS), School of Engineering Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, UK (3) Department of Control Engineering, Czech Technical University in Prague, Technicka 2 Prague 6, Czech Republic Resume : The use of coatings in biomedical field is being widely studied over the past years. In order to attempt the use of such thin films onto orthopaedics implants DLC coatings doped with different contents of Zr have been developed in this research, due to its corrosive and wear properties together to its biocompatibility and low toxicity. The coatings were deposited using dc unbalanced magnetron sputtering in Ar (non-hydrogenated) and Ar CH4 (hydrogenated) discharges onto two different substrates: pure commercial Ti grade 2 and Ti grade 5 (Ti6Al4V). To improve adhesion between film and substrate a functional gradient Ti based layer was deposited (~300nm). The coatings were characterised with respect to structure, adhesion, and mechanical properties.
The tribological properties of the film were evaluated using a unidirectional pin-on-disc apparatus under diluted fetal bovine serum lubrication at 37±3 C° against Ti balls. The contact pressure was adjusted to reach contact pressures similar to that in real knee (50-100Mpa). The friction and the wear resistance was then related with contact conditions and coatings fundamental properties. | 13 21 |
| 16:00 | A study on the properties of the microcrystalline and nanocrystalline diamond films synthesized by a microwave PECVD method Authors : Ahram Jeon1, Yeun-Ho Joung1, Won Seok Choi1,*, Jinhee Heo2, Hyun-Suk Hwang3 Affiliations : 1 School of Electrical Engineering, Hanbat National University, Daejeon 305-719, Korea 2 Materials Safety Evaluation Group, Korea Institute of Materials Science, Changwon 641-831, Korea 3 Department of Electrical Engineering, Seoil University, Seoul 131-702, Korea Resume : Among all the materials in the world, the diamond is the hardest, and is highly resistant to heat, chemical substances, radiation, and wear. The diamond film has high heat conductivity and electrical resistance at normal temperature, a semiconducting property due to doping, low permittivity, and optical transparency within a wide wavelength range. With these excellent characteristics, the diamond film has many applications including as a high-temperature semiconductor and power semiconductor, biosensor, and mechanical parts. We compare properties of microcrystalline and nanocrystalline diamond (MCD and NCD, respectively) films grown on Si (100) substrates by a microwave PECVD (plasma enhanced chemical vapour deposition) with DC bias. The MCD films were grown with conventional PECVD method in a two-step process using biased enhanced nucleation (BEN) whereas the NCD films were grown in a single stage process. To analyze the characteristics of the synthesized film, a field emission scanning electron microscope was used to examine the film thickness and surface conditions. AFM images show the surface roughness of the diamond film. A Raman spectrometer and an X-ray diffraction (XRD) were used to analyze the structure of the diamond film. | 13 22 |
| 16:00 | Deposition of tungsten nitride multilayer thin films by combined magnetron sputtering and nitridation techniques Authors : D. Alegre (1), T. Acsente (2), C. Logofatu (3), G. Dinescu (2), F.L. Tabares (1) Affiliations : (1) Euratom-Ciemat, Av Complutense 22, 28040 Madrid, Spain; (2) National Institute for Laser, Plasma and Radiation Physics, Atomistilor 409 str., Magurele-Bucharest, Romania; (3) National Institute of Material Physics, Atomistilor 105 bis str., Magurele-Bucharest, Romania Resume : The transition from C-based materials to W as plasma facing components in the experimental nuclear fusion reactor requires impurity injection at the plasma edge to enhance radiative cooling and thus to reduce the wall damage. So far the best results have been obtained with N2 in the ASDEX Upgrade tokamak, where also the overall plasma performance was improved upon injection. This could be related to the development of a tungsten nitride (WNx) film resulting in a decrease of the effective W sputtering. In order to test its future use in ASDEX Upgrade, thin layers of WNx were deposited on Si substrates using two different techniques: reactive magnetron sputtering (RMS) and magnetron sputtering followed by plasma nitridation (MSPN). Both types of samples were prepared in a chamber where magnetron sputtering (MS) gun and a plasma source are orthogonally mounted. RMS was performed from pure W targets in an Ar/N2 mixture. Nitrided type samples were prepared repeating the following successive steps: deposition of pure tungsten film by MS and its bombardment with N ions created by the plasma source. Thus, multilayer-like structures were obtained. The contribution will focus on comparison between WNx thin films deposited by RMS and WNx multilayers produced by MSPN combination. To characterize the films SEM, AFM, EDX, XRD and XPS techniques were used. | 13 23 |
| 16:00 | Titanium and aluminium nitride films studied by X-ray diffraction anomalous near edge structure and electron energy loss spectroscopies Authors : M.-H. Tuilier1*, M.-J. Pac1, Y. Pinot1, O. Ersen2, C. Rousselot3, D. Thiaudière4 Affiliations : 1 Université de Haute Alsace, LPMT- PPMR (EA 4365 et CNRS), F-68093 Mulhouse, France. 2 Université de Strasbourg, IPCMS-DSI (UMR CNRS 7504), F-67087 Strasbourg, France. 3 Université de Franche-Comté, FEMTO-ST (UMR CNRS 6174), F-25211 Montbéliard, France. 4 Synchrotron Soleil, Saint Aubin, F-91192 Gif sur Yvette, France. Resume : Several local probes such as X-ray absorption fine structure, diffraction anomalous fine structure and Electron Energy Loss Spectroscopies are carried out on nanostructured Ti1-xAlxN thin films prepared by reactive magnetron sputtering. By combining the selectivity on the lattice symmetry of X-ray diffraction and the typical information given by X-ray absorption spectroscopy, diffraction anomalous fine structure technique allows probing the local environment of Ti atoms present in the crystallized part of the film. N K Near-edge Electron Energy Loss spectra performed in High-resolution Transmission Electron Microscopy experiments on the same set of films are reported. Though the X-ray diffraction fingerprint of Al-rich films (x >0.5) is hexagonal, Ti and N atoms are present in both tetrahedral (hexagonal-like) and octahedral (cubic-like) environments. Ti atoms in cubic-like environment are preferentially located in grain boundaries and prevent the film from cracking in a way. By combining those local probes, it becomes possible to know how the tetrahedral and octahedral sites are shared between crystallized domains and grain boundaries, depending on the composition. | 13 24 |
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