ICMCTF2001 Session BP-1: Symposium B Poster Session
Wednesday, May 2, 2001 5:00 PM in Room Atlas Foyer
Wednesday Afternoon
Time Period WeP Sessions | Topic B Sessions | Time Periods | Topics | ICMCTF2001 Schedule
|
BP-1-1 Cathodic Arc Plasma Deposition of Niobium Nitride Film
T. Zhang, J.H. Song (Beijing Normal University); X.B. Tian, P.K. Chu (City University of Hong Kong); I.G. Brown (Lawrence Berkeley National Laboratory) Two methods of cathodic arc plasma deposition are used to deposit niobium nitride films in a nitrogen ambient: (a) cathodic arc deposition without energetic ion bombardment, and (b) metal plasma immersion dynamic mixing deposition. Smooth and complete niobium nitride film can be fabricated using process (a) at room temperature but not by process (b) unless the temperature is raised to 500ºC. The influences of substrate temperature on the film composition, grain size, and selected orientation are studied for the films deposited using process (b). The films have a selected orientation of (220) at a deposition at 300 ºC and a selected orientation of (200) at 500ºC. The grain size in the films increases as the substrate temperature is increased. The N content in the films initially increases and then decreases as the substrate temperature goes up. |
|
BP-1-2 Magnetron Sputtered Ti-C:H Coatings for Tribological Application
W. Precht (Technical University of Koszalin, Poland) Results of investigations of the deposition process and the properties of Ti-C:H coatings with good tribological properties, especially with low friction coefficient under conditions of dry friction, are presented in this work. The coatings were produced by the reactive magnetron sputtering method where pulsed power supply was used for the magnetron sources and substrate bias. Owing to the pulsed technique it was possible to limit an adverse effect of micro-arc discharges, which occur while sputtering at high concentrations of reactive gas in the working atmosphere and when the reaction product comprises the low conductivity substances. The coatings were deposited under argon and acetylene at different concentrations and the process was controlled using the optical emission spectroscopy. Experiment results on the influence of the working atmosphere composition and the substrate temperatures on the properties of coatings are presented. Observations revealed that at higher concentrations of acetylene in the working gas atmosphere, the content of titanium in the coatings was decreased. At the same time the microhardness and friction coefficient of the coatings were also decreased. The lowest friction coefficient, both with respect to bearing steel (f=0.03) and aluminium (f=0.08), were obtained for the Ti-C:H coatings with titanium content 12 at.%, deposited at 180 ° C. The low value and only slight fluctuations of the friction coefficient, especially between Ti-C:H coatings and bearings steel ball resulted among other things from low surface roughness of the coatings. This low roughness is a result of application of pulsed power supply. Due to those properties of Ti-C:H coatings it is possible to use them for coating the machine elements, especially where oil lubrication should be not possible or limited in use. |
|
BP-1-3 Thermal Stability of Superhard Nanocomposite Coatings Consisting of Immiscible Nitrides
H-D Maennling, DS Patil, K Moto (Technical University Munich, Germany); M Jilek (SHM Ltd., Czech Republic); S Veprek (Technical University Munich, Germany) The requirement of a high thermal stability, which is desirable for many applications, is not met by all superhard nanocomposites which have been reported in the last years 1. In this paper we shall discuss the origin of the high thermal stability of our superhard nanocomposites prepared according to the earlier published generic concept for their design 2. It will be shown that in systems which show a strong thermodynamically driven segregation (i. e. they are immiscible) the nanostructure and the resulting superhardness (measured at room temperature) remain stable up to high temperatures of 1100 ° C. Spinodal decomposition which occurs during the deposition leads to a spontaneous formation of such nanostructure provided the activity of the gas phase is sufficiently high. The latter is fulfilled for plasma CVD of binary nanocomposites, such as nc-TiN/a-Si3N4, W2N/a-Si3N4, nc-VN/a-Si3N4 and others deposited at a relatively high pressure of 1 mbar and high plasma density. In the case of plasma PVD (vacuum arc evaporation or reactive sputtering) which occurs at much lower pressure, the formation of the nanostructure is not fully completed during the deposition. Upon annealing, such nanocomposites show a complex structural relaxation accompanied by an increase of the hardness after which they remain stable up to a high temperature of 1000 ° C. This will be demonstrated by the (Ti1-xAlx)N/a-Si3N4 nanocomposite coatings. Finally, we shall discuss the complex issue of the stability of ternary and quaternary nc-TiN/a-Si3N4/a- & nc-TiSix nanocomposites prepared by plasma CVD under conditions of a lower activity of nitrogen.
|
|
BP-1-4 Structure of ZnO Thin Films Under Varied Conditions of rf Magnetron Sputtering for Varistor Application.
F.S. Mahmood (Government (Emersion) College, Pakistan); R.D. Gould (Keele University, United Kingdom) ZnO thin films were prepared by rf magnetron sputtering. The influence of rf power, rate of deposition and sputtering gas pressure in an ambient of Ar and Ar:O2 mixture on the ZnO thin films structure, density and surface morphology were studied for the development of ZnO-varistor. The deposition rate varies quite linearly with rf power in the ambient of Ar and Ar:O2 mixture. Very low deposition rate was observed at low rf power in the ambient of Ar and Ar:O2 mixture. Thickness of the films increases with increase of rf power. The rate of deposition is also affected by increase in Ar pressure. The introduction of oxygen into the sputtering gas improved stoichiometry of the growing film and decreased in the rate of deposition. The sputtering gas pressure was varied between 0.533 - 1.6 Pa but 1.33 Pa is suitable for the smooth operation of the system and yields good quality films. X-ray diffraction reveals that the diffraction angle for 002 peak shifted from 33.87° to 34.243° at constant pressure. The shift in the 002 peak is associated with intrinsic compression srtresses which occure in film grown at lower sputtering rate. The diffraction angle achieved in best film is 34.25° that is less than the value of 34.45° for ZnO single crystal. Highly oriented 002 films was achieved fron sputtering in Ar:O2 ambient. The films deposited at low deposition rate exhibited a much stronger orientation in the 002 plane and grain size of the order of 216 - 537 nm were obtained from the films deposited by fr power of the order of 100 - 200W in pure Ar pressure 1.33Pa. The cryatallite of large size resulted from mixed orientation. The grain size as function of Ar:O2 mixture in films deposited at rf power 100W in sputtering gas pressure 1.33 Pa was evaluated to be of the order of 720 - 6100 nm which decreases as the content of oxygen increases and density 5.5995 - 5.627 gm/cc increases. |
|
BP-1-5 Synthesis of Titanium Oxide Films by Metal Plasma Immersion Ion Implantation
H. Sun, Y.X. Leng, P. Yang (Southwest Jiaotong University); J.Y. Chen (City University of Hong Kong); J. Wang, G.J. Wan (Southwest Jiaotong University); X.B. Tian, L.P. Wang, P.K. Chu (City University of Hong Kong); N. Huang (Southwest Jiaotong University) Titanium oxide thin films are attractive in the electric, electronic, dielectric, electrocatlytic, chemical, phtoelectrochemical, and optical fields. Recent studies confirm the good biocompatibility of the materials. In this work, titanium oxide films are synthesized using metal plasma immersion ion implantation. Titanium ions emitted from a vacuum arc plasma source are reactively mixed with oxygen in the ambient to produce titanium oxide thin films on silicon. The substrate temperature is maintained at 400C. The films are characterized by Rutherford backscattering spectrometry, x-ray diffraction, atomic force microscopy, and x-ray photoelectron spectroscopy. Scratch tests are also performed to determine the adhesion strength. The results show that the structure changes from an amorphous to rutile nature with increasing oxygen pressure and the ratio of Ti to O changes from 1 : 1.4 to 1 : 1.2. XPS results show that a valence state lower than Ti+4 exists in the film rather than the normal Ti to O ratio of 1 to 2. The scratch tests show that the film adhesion is quite strong. |
|
BP-1-6 Variability of the Corrosion Resistance of 304 and 430 Stainless Steel Samples Coated with TiN in a Triode Ion Plating Reactor New paper created 10/17/00 3:31:34 PM
G.S. Vieira, J.R.T. Branco (Fundacão Centro Technológico De Minas Gerais-Cetec, Brazil); V.C. Lins, M.M.R. Castro (Universidade Federal de Minas Gerais, Brazil) The corrosion resistance of 304 and 430 stainless steel samples coated with TiN, by a triode ion plating reactor, has been evaluated through salt spray and anodic polarization testing. The paper investigates the influence of sample position and orientation in the chamber relative to the Ti source and auxiliary electron source, as well as the variability of the corrosion resistance in a single batch and among different batches. The deposition parameters were kept constant, since the goal was to evaluate the variability of the process. |
|
BP-1-7 Study on the Solid-Liquid Erosion Resistance of Ion Nitrided Metal
K.C. Chen, J.H. He, W.H. Huang (Feng Chia University, Taiwan) Machine parts have often been deteriorated by high speeding liquid or solid particles impact, so that their surfaces have to be more sufficiently protected. Ion nitriding, known to have many advantageous characteristics, may have it's role in the improvement of erosion resistance. Therefore, it may be worthwhile to seek to better understanding its erosion resistance. Hence, the solid-liquid erosion behavior of ion-nitrided S48C carbon steel, pure titanium and Ti6Al4V alloy have been investigated. The results of this study are as follows. The erosion loss among these three raw metals, with the impinging angle the same, S48C is the largest, pure Ti is lesser and Ti6Al4V is the smallest. This is the same as one would expect in the real response from the strength effects of the raw materials. For the ion-nitrided metals, erosion loss is most manifestly decreased on S48C, but then erosion loss in both Ti and Ti6Al4V have no significant change due to their limited case depth and brittle compound layer. However, the erosion resistance in a low-angle impingement is undoubtedly contributed by the compound layer. It is believed that a high hardness nitrided layer would contribute to the kinetic energy absorption of the impinging sand particles in this case. |
|
BP-1-8 Large-Area Deposition of High-Mobility Nanocrystalline Poly-Si Thin Films at Low Temperature Using Unbalanced Magnetron Sputtering
J.-H. Boo, HeonKyu Park, KyungH. Nam, J.G. Han (Sungkyunkwan University, Korea) Poly-Si thin-film transistors (TFTs) are of great interest for the application in large area microelectronics and in particular for active matrix liquid crystal displays. We have deposited nanocrystalline poly-Si thin films on soda-lime glass and SiO2 glass substrates at substrate temperature of below 150 °C using newly developed high rate, high power magnetron sputtering method. To improve the sputtering yield and the growth rate, a magnetic field simulation was in first carried out using a computer program. Based on the results of computer simulation, we built-up the highest power Si magnetron sputtering source that has unbalanced magnetron (Iinner coil : Iouter coil = 2 : 1) with magnetic field of 300 Gauss. Using the home-made high power magnetron sputter source, a nanocrystalline silicon with a mean diameter of 35§¬ were synthesized and the argon plasma as well as single-crystalline silicon target was only used to produce film of nano-sized silicon clusters or crystallites. This is the largest grained nanocrystalline poly-Si among the recently synthesized nanocrystalline poly-Si thin films. The as-grown films were characterized with XRD, XPS, TEM, and Hall measurement. Highly oriented polycrystalline Si(300) films can be grown on soda-lime glass and SiO2 glass substrates under the deposition conditions of 2.0¡¿10-3 Torr of working pressure and 2.5 W/cm2 of the power density. The maximum electron mobilities of the poly-Si thin films deposited on soda-lime glass and SiO2 glass substrates at substrate temperature of 115 °C were obtained 138 cm2/Vsec and 191 cm2/Vsec, respectively. |
|
BP-1-9 Structural Variation of TiN/AlN Nano-Multilayer Film With Heat Treatment
T-Y Seong (Kwangju Institute of Science and Technology (KJIST), Korea); Y.-J. Baik, D-G Kim (Korea Institute of Science and Technology (KIST), Korea) TiN/AlN multilayers with different thickness wavelength from 2.9 to 32 nm were prepared on (100) Si wafer by ion-beam assisted deposition. In this work, we investigated the mechanical properties as well as lattice and microstructural variation. X-ray diffraction and cross-sectional transmission electron microscopy have been used to investigate the microstructural changes of the TiN/AlN multilayers with bilayer periods. Nano indentation hardness and pin-on-disc tribology test have been also employed to take the mechanical properties of the samples. The hardness for the multilayer films with λ>= 4.8 nm was around 22 GPa, whilst the hardness for the samples with λ<= 3.2 nm showed higher than 30 GPa. In addition, to study of structural variation, the samples having 2.9 and 16 nm periods were annealed in Ar atmosphere at temperatures between 800°C and 1100°C. For the sample with lamdba = 2.9 nm, there was no observable microstructural change up to 1000°C except sharpening of diffraction pattern after annealing, while showed grain coarsening at 1100°C. For the sample with λ = 16 nm, on the contrary, a gradual decrease of the hardness occurred with increasing temperature, which was explained with the microstructural change and chemical resistance such as surface oxidation. |
|
BP-1-10 Oxidation Behavior of TiN/AlN Multilayer Films Prepared by the Ion-Beam Assisted Deposition
T-Y Seong (Kwangju Institute of Science and Technology (KJIST), Korea); Y.-J. Baik, D-G Kim (Korea Institute of Science and Technology (KIST), Korea) Multilayered films with nanometer scale modulation of composition are quite interesting in mechanical properties, with a viewpoint of both lattice modification and mechanical property enhancement. To use the multilayer films for mechanical applications e.g. as coatings on cutting tools, the thermal stability and chemical resistance of multilayered structure is ensured because these coatings are exposed to elevated temperature. The oxidation behavior of TiN/AlN multilayers with 2.9 nm and 16 nm bilayer periods was investigated. The multilayer films were deposited using ion-beam assisted deposition and annealed in air at various temperatures between 400°C and 800°C. The formation of the oxides has been confirmed using back-scattered electron images and x-ray diffraction patterns. Auger depth profiling was also used to measure chemical composition variation. There was no evident oxidation of the TiN/AlN multilayers annealed at less than 600°C, and crystalline TiO2and Al2O3 were observed at 800°C. In this study, we examined the oxidation behaviors of the TiN/AlN multilayers with differently layered structures. The coherent TiN/AlN multilayer film showed higher hardness and oxidation resistance than incoherent multilayer film. It was also commented that the oxidation kinetics were changed with annealing temperature. |
|
BP-1-11 Surface Enhancement of CrN Coatings by Metal Plasma Ion Implantation
K.W. Weng, D.Y. Wang (National Chung Hsing University, Taiwan) The chromium nitride (CrN) coating is promising for precision forming and molding applications due to its superior tribo logical properties and environmental-friendly nature. In this study, enhancement of the surface properties of CrN such as dens ity and wetting characteristics were conducted with energetic ion implantation treatment. CrN coatings were deposited using a hybrid PVD and metal-plasma ion implantation (MPII) processing. MPII is a plasma-based ion implantation process based on an ac celerated (10-80 keV) vacuum arc metal plasma source with multiple charge states. At the initial coating stage, low dosage of MPII ion flux helps in effective surface activation and ion mixing. Subsequently, surface treatments of the as-deposited CrN c oating with implantation of metal and/or carbon ions result in densification and phase transformation at a near-surface regime. Wear resistance, corrosion resistance, fatigue strength, and mold-releasing mechanism are significantly improved. The surface study will be followed by series of microstructural and tribological analyses. |
|
BP-1-12 Nanometer-Scale Multilayered AlN/(TiN, VN and ZrN) Films
M.S. Wong, S.Y. Yang, S.L. Hwang (National Dong Hwa University, Taiwan, ROC) Advanced ion-assisted, high-rate, reactive and pulsed-dc magnetron sputtering technique was used to deposit nanometer-scale multilayered films of AlN/TiN, AlN/VN and AlN/ZrN onto Si, glass slide and stainless steel substrates. The interrelation of film processing, microstructure and properties was studied. The thickness of the nanolaminate coating is about 2 ïm and the period thickness is 1-100 nm. It was found that under a critical thickness about 1.6 and 2.1 nm for the AlN layer in the AlN/TiN and AlN/VN, respectively, the films exhibit a highly textured [111] oriented superlattice structure and an enhancement in film hardness. X-ray diffraction and TEM studies indicate that in the highly [111] textured multilayered films, AlN has transformed into a cubic NaCl-form from its normal hexagonal phase. However, in the case of AlN/ZrN films, no highly-textured structure, no cubic AlN phase and no hardness enhancement was observed. For AlN-containing multilayers, the lattice structure and lattice match as well as AlN layer thickness seem to be important for formation of the metastable cubic AlN phase. |
|
BP-1-13 The Investigation of the Property of TiN/AlN Mutilayer by the Improved Cathodic Arc Deposition Technique
M.-S. Leu, J.J. Chang, S.Y. Chen (Industrial Technology Research Institute, Taiwan, ROC) The TiN/AlN multi-layers are produced by an improved cathodic arc deposition system. The thickness of TiN and AlN layers in the muti-layer will be controlled by such an improved method. The film hardness, surface property, color dispersion, elemental composition, oxidation behavior and microstructure are studied in the present work. However, the composition and properties of the coating deposited will be altered due to the fluctuation between TiN and AlN layer structures. Layer structures of the coating are investigated by high resolution TEM examination. Hardness values are attained to about 3000 Hv for this material. Besides, the good addition property (> 50 Newton) and higher oxidation resistant temperature (> 900 °C) are obtained by this cathodic arc deposited TiN/AlN multi-layer. The layer structure of TiN and AlN of the coating can be correlated with the colorimetric result, demonstrating that a dark green color corresponds to a thicker AlN layer and a red-white color corresponds to a thicker TiN layer. Moreover, the thermogravimetric result shows an improved oxidation resistance of the coating when AlN layer is thicker. |
|
BP-1-14 Ti-Based Ternary Nitride Films Synthesized Without Alloy Targets
A. Kimura, H. Hasegawa, T. Suzuki (Keio University, Japan) Arc ion plating method has been widely used to coat cutting tools and sliding parts because it has advantages such as high degree of ionization of evaporated particles and their high kinetic energy. In this method, most of ternary nitride films were deposited from alloy targets which were arc-discharged through nitrogen plasma. In this study, we tried to synthesize ternary nitride films using two metal targets and investigated the compound as a function of distance. Ti1-xAlxN, Ti1-xCrxN and Ti1-xZrxN (0≤x≤1) films were synthesized using Ti, Al, Cr and Zr targets by the arc ion plating method, respectively. Al, Cr and Zr targets were installed opposite to Ti targets in the chamber, respectively. In this investigation, we focused two points: effects of substrate position and arc current on crystal structure and composition of ternary films. After the deposition, micro-hardness of films was measured by the conventional micro-Vickers hardness test with a load of 0.5 N. Lattice parameters and crystal structure were evaluated by the X-ray diffraction method and atomic ratios of Al, Cr, Zr against Ti of films were measured with energy dispersive spectroscopy, respectively. Furthermore, surface and cross-sectional microstructure were observed by scanning electron microscopy. The results of X-ray diffraction analysis showed the peaks of Ti1-xAlxN with NaCl or wurtzite structures appeared by changing substrate position and arc current. The crystal structures of Ti1-xCrxN and Ti1-xZrxN films were all cubic even if the x values and experimental conditions were changed. |
|
BP-1-15 The Properties Aluminum Silicon Oxynitride Thin Films by Filtered Arc Deposition
A. Bendavid, P.J Martin (CSIRO, Australia); H Takikawa (Toyohashi University of Technology, Japan) Thin films of aluminum silicon oxynitride have been deposited on glass substrates and conducting (100) silicon wafers by filtered arc deposition (FAD) under nitrogen and oxygen gas flow. The influence of the substrate bias, oxygen flow ratio, substrate types on the structure, mechanical and optical properties have been investigated. The results of X-ray diffraction showed that the films were amorphous. The optical properties over the range of 300 nm to 800 nm were measured using spectroscopic ellipsometry and found to be strongly dependent on oxygen flow ratio. The refractive index values of the films were found to be in the range of 2.2 to 1.63 at a wavelength of 670 nm for oxygen flow range of 0-100%. The hardness of the films was found to be strongly dependent on the oxygen content in the film. The hardness of the films ranged between 10-24 GPa. The refractive index of the films was to found vary linearly with the residual stress. |
|
BP-1-16 Effect of Wavelength on the Luminescence of Si Nanocrystallites on Si Substrate Fabricated by Pulsed Laser Deposition
J.H. Kim, S.H. Bae, E.S. Shim (Yonsei University, Korea); S.Y. Lee (University of Korea) Si nanocrstallites on p-type (100) Si substrate have been fabricated by pulsed laser deposition technique using a Nd:YAG laser with the wavelength of 355,532 and 1064 nm. The base vacuum in the chamber was down to 10-5 Torr and the pressure of the gas during deposition was varied from 1 to 3 Torr. After deposition, Si nanocrystallites have been annealed at N2 gas. Nitrogen have been used as ambient gases. Strong blue and green luminescence from Si nanocrystallites has been observed in room temperature by photoluminescence and its peak energies shift to green when the wavelength is increased from 355-1064 nm. |
|
BP-1-17 Multilayered Chromium / Chromium Nitride Coatings for Use in Pressure Die Casting.
J. Esteve, A. Lousa, E. Martinez (Universitat de Barcelona, Catalunya, Spain); F. Montala, L. Carreras (Tratamientos Termicos Carreras, TTC, Catalunya, Spain) Chromium nitride coatings are known to give reasonable solutions to the requirements of semisolid forming tools and of pressure die casting of low melting point metals and alloys. These hard coatings have good mechanical behavior when working at high temperatures. They show high hardness, good wear and corrosion resistance and also reduced sticking to the molten or semisolid metal. These good properties are attributed to the formation of temperature stable chromium oxide scales that protect the film against surface interaction with the hot metal. We have developed a related hard coating based on the multilayered stacking of CrN and Cr metal layers. This coating is obtained by reactive-cathodic-arc-PVD on hardened tool steel substrates. The Cr metal inter-layer and the multilayered film structure improve the adhesion of the coating to the steel substrate by reducing the film brittleness and by better matching the thermal expansion coefficients. Multilayered coatings are characterized with respect to their structure, hardness, adhesion and wear behavior and compared for performance to standard CrN single layer coatings. |
|
BP-1-18 Cathode Fracture and Wear of Semiconductor Cathode Vacuum Arcs
J. Niemel, C.C. Klepper, R.C. Hazelton, E.J. Yadlowsky (HY-Tech Research Corporation) HY-Tech Research has studied vacuum arcs with cathodes comprised of boron, B4C, LaB6, and Si, as deposition sources of new and innovative materials. These studies, and those in other laboratories, demonstrate that cathodes made from non-metallic and/or porous materials exhibit uneven cathode wear, thermal shock shattering, and cracking which can result in failure of the arc. These deleterious effects are due to the poor thermal and electrical conductivity of these cathode materials combined with the very localized heating generated by the small arc spot on the cathode surface. The material properties leading to these cathode failure modes are exemplified by silicon which exhibits a sudden 10% decrease in density and a factor of 20 jump in conductivity when it begins to melt. This promotes localization of the arc spot and hole boring through the cathode. Thermal stresses in the material surrounding the melt leads to fracture. Photographs of the damage observed with both pulsed and dc arcs operating with these semiconductor cathodes will be presented and compared with wear observed using graphite cathodes. These pictures show the need to better understand the material properties leading to these undesirable effects and to develop method to mitigate them if successful deposition sources are to be developed. (10 Figures.). |
|
BP-1-19 Mechanical and Tribological Properties of Plasma Deposited Multilayer TiN/Ti and Nanocomposite TiN/SiN1.3 Hard Coatings
P. Jedrzejowski, J. Nohava, M.-A. Raymond, J.E. Klemberg-Sapieha, L. Martinu (Ecole Polytechnique de Montreal, Canada) Plasma enhanced chemical vapor deposition (PECVD) of hard coatings is becoming very attractive due to a possibility to control in a wide range their mechanical behaviour by the appropriate control of precursor gases and the energetics of plasma-surface interactions. In the present work we study two types of PECVD systems: (i) TiN/Ti multilayers obtained from the mixture of TiCl4 with N2, H2 and Ar, and nanocomposite films fabricated from TiCl4/SiH4/N2/H2/Ar mixtures. The mechanical characteristics such as hardness, Young modulus, stress toughness and adhesion were evaluated by microscratch test, depth sensing indentation, pin-on-disc tribometry and by interferometric curvature method. The mechanical and tribological properties are systematically correlated with the film microstructure determined by XRD, SEM, TEM, Microraman, ERD-TOF, Auger spectrometry and AFM. The effect of the film growth energetics in terms of energy per deposited particle and substrate temperature is related to the film properties and microstructure. |
|
BP-1-20 Process Control for the Pulsed-Laser Deposition of YBCO Superconductors
N.C. Boss, R.R. Biggers, J.G. Jones, I. Maartense (Air Force Research Laboratory); G. Perram, R. Rogow (AFIT); T.L. Peterson (Air Force Research Laboratory) Process control is crucial for all deposition techniques. It is especially critical and elusive in the versatile deposition technique known as pulsed-laser deposition (PLD). PLD produces a plume of highly energetic components directed onto a suitable substrate. The quality and character of the subsequent film is largely determined by plume dynamics, substrate/film-surface conditions, and post-deposition annealing. PLD plume dynamics are complicated and not well understood. Improved PLD process control can be accomplished with real-time autonomous fuzzy logic control based on time-of-flight (TOF) information gathered from various plume components at multiple sensor positions along the plume path. Manual and fuzzy logic based regulation of laser beam energy, energy density, and chamber ambient pressure based on this TOF feedback has resulted in improved film quality and reproducibility. This process control can be extended to most PLD materials by substituting different narrow-band optical filters that pass the collision driven emissions of plume components. |
|
BP-1-21 Influence of Low Energy Ion Implantation on Mechanical Properties of Magnetron Sputtered Al-Cr-N Thin Films
S. Sattel, P. Pesch (TZO GmbH, Germany); R. Loos, M. Stueber, S. Ulrich, H. Holleck (Forschungszentrum Karlsruhe, Germany) Metastable, nanocrystalline, ternary chromium aluminium nitride thin films have been deposited by reactive and non reactive unbalanced magnetron sputtering of a chromium aluminium nitride target in a pure nitrogen and a pure argon atmosphere, respectiveley. The film constitution is examinated by micro probe analysis, X-ray defraction, transmission electron microscopy and high resolution electron microscopy. The mechanical properties such as vickers hardness and internal stress have been determined as a function of ion energy of bombarding particles during film growth. It could be shown, that the dependence of these properties on ion energy can be described by two physical mechanisms, both, subsurface ion implantation and ion bombardment induced increase of mobility. |
|
BP-1-22 Industrial Applications of Laser-Arc Deposited Superhard Amorphous Carbon Films (DIAMOR)
H.-J. Scheibe, S. Grosser, C.-F. Meyer, B. Schultrich (Fraunhofer Institute for Materials and Beam Technology, Germany); H. Schulz (Darmstadt University of Technology, Germany); H. Schwach (Fraunhofer Institute for Materials and Beam Technology, Germany) Superhard amorphous carbon films has been prepared by a special pulsed vacuum arc deposition technology (Laser-Arc). In the Laser-Arc technology the arc discharge is guided on the cathode surface in a highly controlled manner by the igniting laser pulses. A very regular erosion of the cathode material is achieved by linear scanning of the laser beam and rotation of the cylindrical formed cathode made from graphite. The film deposition is carried out at low temperatures (below 100°C). Therefore, also temperature sensitive materials, e.g. plastics, Al-alloys, brass, bronze and stainless steel, can be coated without damaging. The resulting films are smooth, have a low internal stress (about 1 GPa) and good thermal stability (up to 400°C at open air). Because of their very high hardness (40 to 70 GPa) and their low friction coefficient (0,10 - 0,15), they are successfully applied as wear resistant coatings. They have been successfully tested, especially at severe such tribological condition, e.g. for work without or with a minimum consumption of lubricants. Their potential will demonstrated by representative examples. Results of industrial tests of Diamor® coated parts and tools are presented. The special advantages of Diamor® for very different demands are discussed. A newly developed Laser-Arc module for the retrofit of industrial standard deposition devices is presented. This line-source with a length of more than a meter shows the potential for the industrial scale up of Diamor® deposition. |
|
BP-1-25 Structure and Tribological Properties of Titanium Oxide Formed by Oxygen Plasma Immersion Ion Implantation into Titanium
K. Volz, W. Ensinger (Philipps-University Marburg, Germany) Titanium and Ti6Al4V are known for their remarkable mechanical and chemical properties. Since both materials exhibit poor tribological properties, the use of surface treatments is recommended. Titanium and Ti6Al4V have been treated by oxygen-plasma immersion ion implantation (O2-PIII) to form protective oxide surface layers. The oxide formation has been investigated for dependence on the ion density of the plasma, pulse repetition rate and pulse number, corresponding to process time. Sets of samples have been prepared at different implantation temperatures. The composition of the modified surface layer has been evaluated by X-ray photoelectron spectroscopy. At low temperature, the amount of incorporated oxygen and its depth distribution is determined by ion-solid-interactions. With increasing temperature the oxygen distribution was determined by both implantation and diffusion. Phase characterization assessed by cross-section transmission electron microscopy has shown the formation of rutile TiO2- and α-TiO in titanium for high temperatures. Pin-on-disc tests with metal or polymer counterbodies showed that the oxide reduces wear considerably. The dependence of the tribological performance on process parameters and the resulting morphology is discussed. |
|
BP-1-26 Effect of Nitrogen and Oxygen on the Surface Characteristics of 304 Stainless Steel Films Synthesized by Unbalanced Magnetron Sputtering Process
S.Y. Lee, G.S. Kim, B.S. Kim (Hankuk Aviation University, Korea) The N- or O-doped 304 stainless films were synthesized by unbalanced magnetron sputtering process with various argon and reactive gas (N2, O2) mixtures. These films were examined by SEM, XRD, AES, and Koop microhardness tester The results from X-ray diffraction(XRD) analysis showed 304 stainless film synthesized without reactive gas using a bulk 304 stainless steel target had ferrite bcc structure(αphase), while N-doped 304 stainless film was consisted of nitrogen supersaturated fcc structure, which showed a strong γ(200) phase. In the O-doped films, oxide phases(Fe2O2O 3and Cr2O2O3 were observed from films synthesized under a condition of O2flowing more than 9sccm. AES analysis showed that nitrogen content in N-doped films increased as the nitrogen flow rate increased. Approximately 43 at.%N in the N-doped film was measured using a nitrogen flow rate of 8sccm. In O-doped film approximately 15 at.%O was detected using a O2 flow rate of 12sccm. Koop hardness of N-doped film using a nitrogen flow rate of 8 sccm was measured to be approximately Hk 1200 and this high value could be attributed to the fine grain size and high amount of residual stress in the film. Detailed results will be presented. |
|
BP-1-27 The Relationship Between Adhesive Toughness and Wear-Resistant Performance of CVD Diamond Coatings on Cobalt-Cemented Tungsten Carbide Cutting Tools
H. Takahashi, S. Kamiya (Tohoku University, Japan); H. Liu (OSG Corporation, Japan); M. Saka, H. Abé (Tohoku University, Japan) High hardness of diamond coatings produced by low-pressure chemical vapour deposition (CVD) methods has been already utilized as wear-resistant coatings on cutting tools. However, its brittleness tends to cause delamination, which limits the endurance of coated tools before they wear out. In this report, we surveyed the correlation between the adhesive toughness of diamond coatings on cobalt-cemented tungsten carbide (WC-Co) substrates and the endurance of coated tools under cutting operation. The toughness of interface was quantitatively evaluated by a method recently developed by the authors. We prepared the specimen where the film was projected a little out of the edge of the substrate. The vertical load was applied to push up the interface side of projected film in order to extend the crack along the interface. On the basis of the load required to extend the interface crack, the adhesive toughness was evaluated in comparison to the finite element model (FEM) simulation. Various diamond coatings were deposited under different conditions such as different methane concentrations in the source gas mixture and consequently had various crystalline structures. The adhesive toughness showed an interesting behaviour depending on the deposition conditions. We performed cutting tests on the tools with these various coatings and obtained the data of their endurance. Based on the results of cutting tests and adhesive toughness measurement, discussion would be finally focused on the possibility to obtain an optimized adhesive properties of diamond for the best performance as wear protection coatings. |
|
BP-1-28 Evaluation Of Duplex Plasma Electrolytic Nitrocarburising And Plasma Immersion Ion Assisted Deposition Of Diamond Like Carbon Coating Of AISI 304 Stainless Steel.
C. Tsotsos, A.L. Yerokhin, A.D. Wilson, A. Leyland, A. Matthews (University of Hull, United Kingdom) In our previous studies it was demonstrated that the tribological performance of stainless steels can be improved by applying a duplex surface treatment of plasma electrolytic nitrocarburising (PEN/C) and plasma-immersion ion-assisted deposition (PIAD) of a diamond like carbon (DLC) coating. Diffusion hardened layers between 15-60µm, consisting primarily of expanded austenite provided improved wear resistance and enhanced load bearing capacity for the PIAD DLC low-friction coating. In this paper further investigations are reported regarding the tribological and mechanical properties of these duplex treatments in sliding wear tests against sintered WC-Co and SAE 52100 chromium-steel counterfaces using a low frequency (5Hz) reciprocating ball-on-plate geometry with a sliding distance of 1000m and a range of loads between 10N and 25N. The friction coefficient remained remarkably similar for this range of loads (i.e. µ= 0.09-0.13 and µ=0.24-0.32 for WC-Co and SAE 52100). The primary wear mechanism observed is one of mild asperity deformation and polishing and, in extreme cases, minor delamination of the DLC coating. The volumetric wear coefficient was almost constant, for loads up to 15N, particularly when sliding against WC-Co, where material loss from the ball counterface is less severe as than with SAE 52100, despite the higher contact pressure at an equivalent load. No failure of the coating was observed for 10, 15N loads against WC-Co and at up to 25N against steel, maintaining low friction coefficient. Scratch and impact tests were used to further evaluate the load-bearing capacity and adhesion of the coatings. Scanning electron microscopy was employed to assist in the evaluation of the wear behaviour and failure mechanisms, with EDAX used to investigate material transfer to the coated surface. |
|
BP-1-30 Characterization of Ti-Al-N Films Produced by Reactive Sputtering of Titanium Aluminum Sputtering Targets
E Ivanov (Tosoh SMD Inc.,) Nanocrystalline titanium-aluminum-nitrogen films of about 500 nm thickness were reactively sputter deposited onto (100) Si substrate by using dc magnetron sputtering of Ti-Al target materials with differen compositions. The properties of these films were investigated by using sheet resistance measurement, DTA and x-ray diffraction. Particles on wafer data were collected. The composition and structure of the film depended on the composition of the target material and nitrogen backfill during sputtering. Increasing the amount of nitrogen in the sputtering gas increased the resistivity of the film. The target microstructure plays important role in the film microstructure and resistivity. The erosion surface of the multiphase target material was analyzed with SEM and EDS. |
|
BP-1-31 Characterization of Unbalanced Magnetron Discharge by Fitting Cylindrical Langmuir Probe Data
M. Zlatanovic, I. Peric (University of Beograd, Yugoslavia) Preliminary investigations of a balanced magnetron system demonstrated the possibility of metallic Ti and Ti-6Al-4V film deposition onto glass substrate. In order to deposit the coatings in reactive mode the additional permanent magnets were mounted in the vacuum chamber and the system for reactive gases flow had been installed. The unbalanced magnetic field configuration in the deposition volume was measured by the Hall probe and various voltage-current characteristic of the magnetron discharge were presented. The axial and radial distributions of the maximum ion current density were measured by the Langmuir electrostatic probe. The classical expression for Langmuir probe characteristics was modified in order to describe non saturating probe ion current in this unbalanced magnetron discharge used for thin film deposition. The modified relation was successfully applied as the fitting function for the experimental data which provided the measurement of electron temperature, electron density and plasma potential. It has been shown that the current density of the substrate bombarding ions may be far in excess of 1 mA/cm2. The relation for the probe characteristics is given which was used as the fitting function for the experimental data. This equation contains three magnetron discharge parameters: electron temperature, electron density and plasma potential. These parameters can be calculated from the probe characteristics by using the derived equation as the fitting function. The results of Levenberg Marquardt fitting procedure were given. The value of x2 as low as 6.8x10-11 was obtained which confirms a strong agreement between the theory and experiment. The following values of plasma parameters were calculated: n=9.98x1016 m-3; Te=3.13eV i Vp=8.9V. |
|
BP-1-32 Ion Vapor Deposition, A Plasma Assisted Vacuum Deposition Process
J. Zhou, M. Bridger (Ipsen International, Inc) The Ion Vapor Deposition (IVD) process is an electromagnetic deposition process. Film growth takes place when coating material is heated and vaporized by ionization and transported to the substrate, where it condenses. The IVD process can be used to deposit thin films of pure materials or compound materials. This paper will discuss the basics of the IVD process and its utilization in various applications. The primary focus will be on the operational principles of two basic types: barrel coaters and rack coaters. The design parameters used for each will be discussed along with their advantages and disadvantages. |
|
BP-1-33 Structural Transitions in Hard Si-Based TiN Coatings: The Effect of Bias Voltage and Temperature
F. Vaz, L. Rebouta (Universidade do Minho, Portugal); P. Goudeau (Universite de Poitiers, France); J.P. Rivière (Université de Poitiers, France) This paper reports on the preparation of (Ti,Si)N films by r.f. reactive magnetron sputtering. X-ray diffraction (XRD) results revealed the development of a two face-centred cubic phase mixture (lattice parameters of 0.429 nm: phase 1 - TiN and 0.418 nm: phase 2) in the presence of ion bombardment of the growing film. On the other hand, without this ionic bombardment, only phase 2 was detected. Although the exact nature of its composition is more difficult to evaluate, it is most likely a Ti-Si-N structure, where some of the Si atoms are occupying Ti positions within the TiN lattice. This would explain the low value of the lattice parameter. Regarding structural transitions, phase 1 changed from <111> to <220> and finally to a week <200> texture with increasing Si contents. For phase 2, the possible structural changes are difficult to distinguish, although, in the cases of ion bombardment, it seems that they tend to follow those of phase 1. Anyway, the increase in deposition temperature revealed that phase 2, clearly visible at 200 °C, is progressively disappearing as demonstrated by the result of one sample prepared at 500 °C, where this phase cannot be identified. A significant increase in hardness was observed in this sample when compared to the one prepared at 200 °C, revealing the crucial importance of these structural changes. In order to verify, not only the effect of phase 2 in mechanical behaviour, but also its structural transitions, this paper will also report on the results obtained from unbiased (Ti,Si)N samples (only phase 2 is present), and for increasingly deposition temperatures. An empirical model describing phase formation and structural transitions with deposition conditions will be discussed. |
|
BP-1-34 Silicon/Silicon Oxide Coating on AISI 304 Stainless Steel by CVD in FBR: Analysis of Silicides Formation and Adhesion of Coatings
F.J. Pérez, M.P. Hierro, M.C. Carpintero, F. Pedraza, C. Gómez (Universidad Complutense de Madrid, Spain) Silicon/mullite multilayers are designed to protect materials against high temperature corrosion. In order to avoid the metallic/ceramic interphase, a oxidation of silicon deposited have been performed. The deposition of this multilayer systems is performing using CVD in Fluidized bed reactor (CVD-FBR). The preliminary results of Silicon and silicon oxide coatings onto AISI 304 stainless steel by CVD-FBR obtained at 450°C for different processing times will be shown. Moreover, the effect of subsequent thermal treatments, in the formation of brittle silicides, were analysed. The relationship between coating process, heat treatments, and mechanical adhesion was established. |
|
BP-1-35 Ion Implantation as a Surface Modification Technique to Improve Localised Corrosion of Different Stainless Steels
F.J. Pérez, M.P. Hierro, C. Gómez, L. Martinez, P. Guzman (Universidad Complutense de Madrid, Spain) Ion implantation is a surface modification technique which affects the surface properties without changing the bulk ones. In this work, the effect of Silicon and Argon implantation on different stainless steels (AISI 304, AISI 317 and AISI 430) is discussed. Silicon was implanted in order to improve the corrosion properties of those stainless steels by generating a Si- rich region near the surface. Argon, as a noble gas, is supposed that has no chemical but physical effects on the bulk. Different implantation doses (1x1014, 5x1014, 1x1015 ions/cm2) at an energy of 80KeV have been tested to optimise the implantation dose for each steel. Theoretical simulations using TRIM 96 computer code have been performed in order to estimate the depth profiles and to optimise the implantation parameters. The corrosion measurements were carried out in NaCl solution by using electrochemical impedance spectroscopy (EIS). The surface have been characterised by SEM,AES and XPS. The experimental results showed that the effect of Si and Ar implantation depends on the microstructure and composition of the stainless steels. Less compact structures and less amount of alloying elements (as occurs with AISI 430) achieve bigger changes with this modification, whereas stainless steels with a larger amount of alloying elements and more compact structures (AISI 317) slightly modifies the corrosion behaviour with ion implantation. |