Symposium CH
Ceramic Thin Films and Coatings for Protective, Tribological and Multifunctional Applications

CH:KL  Funtional Surfaces and Coatings - New ceramic technologies for the benefit of industries and mankind -
R. GADOW, University of Stuttgart, Stuttgart, Germany

Product development with advanced coating  technologies is a key issue in competitive modern industries. Processing of sub-micron and nano scale powders by modern thermal spray techniques offers new potentials for high performance oxide ceramic, metallurgical and cermet coatings. Air Plasma Spraying (APS), High Velocity Oxyfuel (HVOF) and High Velocity Suspension Flame Spraying (HVSFS) have been developed for thermal spraying of fine powder agglomerates and suspensions, containing micron, submicron and especially nano particles with hypersonic projection speed. For this purpose suspensions are introduced directly into the combustion chamber of a novel HVSFS torch, thereby featuring safe work place conditions while handling nano powders. Dense and well adherent coatings with a refined microstructure are obtained. Especially from nano structured coatings superior physical properties are expected for various industrial applications. Thermal spray deposition of coatings is related to an intensive heat and mass transfer between the torch and its plasma plume or hot gas jet respectively and the substrate to be coated. The thermal load during processing can be controlled by fast movement with appropriate robot kinematics and trajectories arrangement and / or by simultaneous cooling. Thereby thermal stresses and process induced residual stresses can be controlled or even be optimized to a certain extent. This is an essential for the compatibility of various coating solutions as well as for reproducibility and reliability of coatings and multilayer structures under thermal and mechanical cyclic load and under operational conditions. Ultrahard coatings cannot be machined or finished with conventional cutting or milling operations. To achieve best surface properties and lowest dimensional tolerances the complete manufacturing chain must follow a stringent net shape approach. In many applications this means the employment of sophisticated robot trajectories to meet these aims and scopes. Main applications are ceramic coatings for cylinder liners in high performance car engines with reduced internal friction, functional coatings for extreme tribological conditions in printing machines and high speed train wheel suspensions. Further applications are shown for biomedical and energy conversion systems, including key components for nuclear fusion reactors.


Session CH-1 - Advances in Deposition, Surface Modification and Characterisation Techniques

CH-1:IL01  Observing Unobservable: Active Diagnostics of Electrolytic Plasma Processes for In-situ Identification of Surface Properties
A. YEROKHIN, University of Manchester, Manchester, UK

Advanced manufacturing relies upon on-demand production of bespoke components. This presents the major challenge for surface engineering techniques that should be both robust and adoptive to allow required characteristics of surface layer to be obtained on components with different sizes and geometries, without preliminary trials. Addressing this challenge requires development of diagnostic tools for identification of surface properties that are unobservable in-situ and models linking these properties to processing parameters. This is particularly vital for plasma-assisted electrolytic surface treatments that attracts significant interest as environmentally friendly alternatives to REACH-restricted acid-based processes, e.g. electro-polishing and anodising. An overview is provided to present understanding of electrolytic plasma surface treatments of Al, Mg, Ti alloys and steels, as well as approaches to their diagnostics and modelling. Discussion is developed on how this may help revealing the multiscale nature of the treatments that can be described by the processes separated by several orders of magnitude in the time scale and how these processes are linked to characteristics and properties of the surface layer for selected examples of electrolytic plasma processing systems.


CH-1:IL02  Cold Spray: From Coating to Additive Manufacturing 
B. JODOIN, D. MCDONALD, P. DUPUIS, Y. CORMIER, University of Ottawa, Ottawa, ON, Canada

Additive Manufacturing (AM) refers to the various technologies used to build 3D objects by adding layer-upon-layer of material. This contrasts with traditional manufacturing methods (TMM), in which subtractive (milling/drilling), formative (casting/forging) and joining (welding/fastening) processes are used. AM can result in lower production costs and environmental footprint than TMM. AM of plastic parts is considered state-of-the-art. However, AM of metals and ceramics requires more extensive research and development efforts to expand the scope of applications to high-performance structural parts. Early successes of organisations, such as General Electric and NASA, have confirmed an interest in AM and the potential of AM is contributing to the slow transition from TMM to AM in the aerospace sector. In recent years, uOttawa researchers have been instrumental in advancing the engineering science of Cold Gas Dynamic Spray Additive Manufacturing (CGDSAM). CGDSAM is still in its infancy, and can be considered as a (solid state) Material Jetting AM process. The work will present the CGDSAM process fundamentals, the advantages and disadvantages of the process compared to other AM processes and provide examples of parts that have been produced by CGDSAM using a variety of materials.


CH-1:IL03  Deposition Mechanisms in Hybrid Molecular Beam Epitaxy of Complex Ceramic Oxides
R.P. HARKINS, TIANQI WANG, A. PRAKASH, C.J. CRAMER, B. JALAN, W.L. GLADFELTER, Departments of Chemistry and Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, USA

A combined experimental and computational study on the use of tin alkyls as precursors to epitaxial, single crystalline films of tin oxide and tin-doped perovskites in a hybrid molecular beam epitaxial system will be presented.  Incorporation of tin into MBE-grown perovskite films such as BaSnO3 is difficult using elemental sources of tin. Hybrid MBE, in which the elemental source for tin has been replaced with a molecular source, successfully yields stoichiometric BaSnO3. Despite deposition temperatures exceeding 700°C, the choice of the molecular precursor appears to be important. Use of hexamethylditin (HMDT) as the tin source yields phase pure, stoichiometric perovskite films while tetraethyltin (TET) yielded tin-deficient BaSnO3. Details of the deposition process and film characterization will be presented. Thermochemical properties of the tin alkyl precursors were calculated using the W1-F12 ab initio method and were used to predict the relative stability and equilibrium concentrations of tin alkyl fragments in the gas phase. The results of calculation of possible kinetic pathways for activating the precursors on different crystallographic faces of the rutile form of tin oxide will also be discussed.


CH-1:IL04  Plasma Enhanced Magnetron Sputter (PEMS) Deposition of Ceramic Coatings for Extreme Environments
RONGHUA WEI, Southwest Research Institute, San Antonio, TX, USA 

Thick TiSiCN-based ceramic coatings have been developed using a plasma enhanced magnetron sputtering (PEMS) process. The coatings thus formed have a microstructure composed of nanocrystalline TiCN with the grain size of 4-10 nm in a matrix of amorphous SiCN, or nc-TiCN/a-SiCN. The microstructure of the coatings results in the super-hardness (up to 4600HV). However, the internal stress was found to be less than 1 GPa due to the enhanced ion bombardment, thereby allowing the deposition of ultra-thick coatings of over 500 µm. The coatings also have high toughness. The nanocomposite coatings have been developed specifically for severe environments including sand erosion, sand abrasion, water droplet erosion, and heavy load sliding wear for various Fe-based and Ti-based alloy substrates. In this presentation we will present the microstructural, mechanical and tribological studies of these coatings in severe environments. The mechanisms of the enhanced wear resistance of the coatings are proposed. Finally, examples of industrial applications are presented including compressor blades for aero engines; ball valves, valve stems, valve seats, pump liners and plungers for the oil and gas industry; and piston rings for the automotive industry.


CH-1:IL05  High Velocity Flame Spraying (HVSFS) of Nano-structured Coatings and Related Industrial Applications
R. GADOW, A. KILLINGER, University of Stuttgart, Institute for Manufacturing Technologies of Ceramic Components and Composites (IFKB), Stuttgart, Germany

Various thermal spray technologies including plasma and supersonic flame spraying have shown their potential in the production of dense and well adherent structural and functional coatings on metal, ceramic and even polymer substrates. Thermal spraying using liquid precursors or suspensions, containing fine and ultra fine powder particles enables the development of coatings with unique microstructure and beneficial features, that significantly differ from conventionally sprayed coatings. The potential of these novel coatings is well known and has gained vital interest among the scientific and industrial community. It is expected, that thermal spraying with liquid feedstocks will give substantial contributions in numerous industrial key applications like biomedicine, energy conversion, catalysis, automotive and aerospace engineering. Fabrication routes and processing of solutions and suspension feedstocks containing nano sized particles strongly differ from conventional spray materials preparation. Especially in case of suspensions, their storage and handling requires distinct expertise. Flame interaction of liquids and suspensions as well as coating formation phenomena are key issues to gain the necessary process knowledge. This is required to fully control and shape the liquid feedstock based spray process and raise the technology to an industrial production level. The presentation gives an overview about current research activities in hard ware component and process development and will discuss potential industrial applications.


CH-1:IL06  Non Reactive High Impulse Magnetron Sputtering of Oxide Ceramics
R. GADOW, A. KILLINGER, Institute for Manufacturing Technologies of Ceramic Components and Composites, University of Stuttgart, Stuttgart, Germany; B. GAEDIKE, M. LUIK, Hartmetall-Werkzeugfabrik Paul Horn GmbH, Tuebingen, Germany

Carbide cutting tools for machining operations (e.g. milling or turning) are coated by physical (PVD) or chemical vapor deposition (CVD) to meet the requirements of different cutting operations. Most industrial PVD magnetron sputter facilities need a minimum electrical conductivity of their target materials as they work in DC mode. Therefore the use of ceramics (typically with low electrical conductivity) leads to a disappearing anode effect. However ceramics have excellent mechanical properties such as high resistance to thermal shocks and oxidation. These mechanical properties are interesting for cutting operations in new materials (e.g. titanium alloys and austenitic nickel-chromium-based superalloys). A new approach to make oxide ceramics available as target materials in non-reactive high-power impulse magnetron sputtering (HiPIMS) is presented. Following this approach first ZrO2 based coatings have been produced. Morphology and mechanical properties of the coatings like scratch behavior will be presented and discussed.


CH-1:L07  Aerosol Deposition: A Top-down Approach to Nano-crystalline, Functional Ceramic Films and Tribological Coatings
P.A. FUIERER, Materials & Metallurgical Engineering Dept., New Mexico Tech, Socorro, NM, USA

Aerosol deposition (AD) or vacuum kinetic spray (VKS) refers to a novel process for the fabrication of ceramic films based on the high velocity impact of fine particles upon a substrate. The process offers exciting possibilities for both rapid prototyping and large scale manufacturing of thick film functional, tribological, and protective coatings because of several attributes: a wide range of film thickness (nanometers to tens of microns), high deposition rate, and room temperature processing. Moreover, AD results in unique microstructures with beneficial characteristics including nano-crystallinity and near theoretical density. As we learn more about the deposition mechanisms via high strain rate deformation and particle fracture and re-bonding, we can identify optimal process parameters for a wider variety of ceramics. This talk will describe the unique microstructure, texture, and stress state of AD films produced in our laboratory as revealed by SEM, AFM and scanning white light profilometry. Properties and performance will be presented for AD ceramic coatings ranging from soft (eg. molybdenum disulfide) to hard (eg. silicon carbide), semi-conducting (eg. silicon) to insulating (eg. alumina).


CH-1:L08b  Microstructural Characteristics and Corrosion Resistance of Atmospheric Pressure Chemical Vapor Deposited SiO2 Films from TEOS and O2
S. PONTON, F. DHAINAUT, CIRIMAT and LGC, Toulouse, France; H. VERGNES, B. CAUSSAT, LGC, Toulouse, France; D. SAMÉLOR, D. SADOWSKI, C. VAHLAS, CIRIMAT, Toulouse, France

Chemical vapor deposited SiO₂ films from tetraethyl orthosilicate (TEOS) is a key enabling material in numerous applications. Among the several pathways for the CVD of SiO₂ films from TEOS, the poorly investigated medium temperature process involving oxygen ensures a compromise between the high thermal load of the surface reaction of the TEOS pyrolysis process, and the strong activation of gas phase reactions in the ozone assisted decomposition of TEOS. It is a promising route towards conformal coverage of complex-in-shape structures, growth rate control, and appropriate physical & chemical properties of the coating. SiO_x films are obtained from TEOS+O₂ in a horizontal CVD reactor operating at atmospheric pressure between 350 and 500°C. FTIR operating under normal and 55° incidence angle is used for the investigation of the structure, namely density, strain, oxygen content and stoichiometry of the films, by probing vibrational modes in the 900-1300 cm^-1 region with well-resolved TO-LO phonon splitting. Complementary density values obtained by ellipsometry allow estimating the porosity of the films. Their corrosion resistance is investigated by the P-Etch test through thickness loss and is correlated with their composition, porosity and density.


CH-1:L10  Silicon Oxycarbide Coatings by Low Pressure Chemical Vapour Deposition
F. DEMEYER, S. JACQUES, Y. LE PETITCORPS, University of Bordeaux, CNRS, Safran, CEA, Laboratoire des Composites Thermostructuraux (LCTS), UMR 5801, Pessac, France; A. DELEHOUZE, Safran Ceramics, Safran Group, Le Haillan, France

The usual manufacturing processes for silicon oxycarbide (SiOC) glasses are the sol-gel route or the polymer derived ceramic route. The present work describes a less common one-step process for SiOC preparation: Low Pressure thermal Chemical Vapour Deposition (LPCVD), which is broadly used for the preparation of other ceramic coatings. SiOC coatings of various compositions were deposited using this CVD method. The deposition runs were carried out at three different hot zone temperatures (750 °C, 950 °C and 1100 °C) and two different pressures (0.5 and 1.5 kPa). The coatings were characterized by Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectrometry (SEM-EDS) and by Raman spectroscopy. Thickness profiles were measured as a function of temperature. The results show very high deposition rates for a LPCVD process: from 2.9 µm.h-1 (950°C, 0.5 kPa) to 54 µm.h-1 (998°C, 1.5 kPa) with a gas flow rate of SiOC precursor of only 4 sccm. Apparent activation energies were determined for the different condition sets. EDS results show the carbon content of the coating increases with temperature.


Session CH-2 - High Temperature Protective Coatings in Oxidising and Harsh Environments

CH-2:IL01  Environmental Barrier Coatings for All-oxide Ceramic Matrix Composite Combustor Liners
P. MECHNICH, German Aerospace Center (DLR) Institute of Materials Research, Koeln, Germany

A key to the application of ceramic matrix composites (CMC) in harsh environments are environmental barrier coatings (EBC). A high resistance of EBCs against hot corrosion by water vapor and inorganic aerosols is mandatory for demanding high-temperature loaded CMC components such as combustor liners of turbine engines. Y2O3-stabilized ZrO2 (YSZ), YAG and Y2O3 were evaluated as EBC materials for Al2O3/Al2O3 CMC. Laboratory-scale specimens as well as prototypic CMC components were coated by means of air plasma spraying (APS), respectively. All investigated EBC materials revealed a favorable corrosion resistance in a high-velocity combustion atmosphere. YSZ and YAG EBC are prone to degradation by inorganic aerosols commonly referred to as CMAS, whereas Y2O3 showed a very promising CMAS resistance. YSZ and YAG and are inherently compatible with Al2O3, i.e. do not react at high temperatures. Y2O3-EBC and Al2O3-CMC form a thin interdiffusion and reaction zone consisting of a sequence of thermodynamically stable Y-aluminates which, however, did not seriously affect coating adherence. APS Y2O3 exhibited the most promising combination of materials properties to be used as EBC for prototypic Al2O3/Al2O3 CMC combustor liners. The viability of the concept could be proved in a high pressure.


CH-2:L02  Materials for Very High Temperature Solar Receivers
J. COLAS, L. CHARPENTIER, M. BALAT PICHELIN, PROMES-CNRS, Font-Romeu Odeillo, France; M. PONS, F. MERCIER, D. CHEN, SIMaP, St-Martin-d’Hères cedex, France; D. PIQUE, SIL’TRONIX ST, Archamps, France

The efficiency of Concentrated Solar Power Plants can be improved by an increase of the outlet temperature of the coolant circulating in the solar receiver. However current receiver materials are limited by their maximal temperature (around 1200 K). Consequently new materials have to be developed. One of the main challenges concerns the durability of the solar receiver, and more precisely its resistance to high temperature oxidation in air, thus protective coatings have to be used. The REHPTS (High Pressure and Temperature Solar REactor) set-up, implemented at the focus of the 6 kW solar furnace in Odeillo (France) was used to study as-received and coated metallic samples. Samples coated with AlN elaborated by HT-CVD at SiMAP laboratory (Grenoble) have been characterized before and after high temperature exposure in air by XRD, Raman, 3D profilometry and reflectivity measurement. High temperature oxidation was conducted on AlN-coated TZM (Mo alloy), on Fecralloy (coated or not) and on Inconel 625 (coated or not). Coated TZM showed poor oxidation resistance, probably due to the coating deposition. However coated Fecralloy seems to be more resistant to oxidation than uncoated samples. New studies are ongoing to understand better the impact of the coating.


CH-2:L03  Superior High-temperature Behavior of Amorphous Coatings from Quinary Hf-B-Si-C-N System
P. ZEMAN, S. ZUZJAKOVA, R. CERSTVY, J. VLCEK, Department of Physics and NTIS - European Centre of Excellence, University of West Bohemia, Plzen, Czech Republic

The present study focuses on systematic investigation of high-temperature behavior of two amorphous Hf-B-Si-C-N coatings with different electrical and optical properties. The coatings were prepared by reactive pulsed dc magnetron co-sputtering of a B4C-15%Hf-20%Si target in two Ar+N2 mixtures (15% and 20% N2 fractions). Particular attention is paid to thermogravimetric analysis and differential scanning calorimetry of the coatings in air and Ar, and to the evolution of the film structure, microstructure and elemental composition with increasing annealing temperature from 1100°C to 1700°C. The coating prepared at the 15% N2 fraction has an elemental composition of Hf7B23Si22C6N40 and is electrically conductive, while the coating prepared at the 20% N2 fraction has an elemental composition of Hf7B23Si17C4N45 and is optically transparent. Both coatings are sufficiently hard (≈ 20 GPa) and exhibit a superior oxidation resistance up to 1600°C due to the formation of a nanocomposite diffusion barrier surface layer consisting of HfO2 nanocrystallites surrounded by a borosilicate amorphous matrix. A small difference in the composition results, however, in a different thermal stability of the amorphous structure of the coatings above 1400°C when the Hf7B23Si22C6N40 coating crystallizes.


Session CH-3 - Thermal Barrier Coatings

CH-3:IL01  Present and Future of Thermal Barrier Coatings
R. VASSEN¹, D.E. MACK¹, O. GUILLON^{1, 2}, ¹Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), Jülich, Germany; ²Jülich Aachen Research Alliance: JARA-Energy

Thermal barrier coatings (TBCs) nowadays are extensively used to enable enhanced efficiency in gas turbines for both energy and aviation sector. Various thermal spray technologies are used for the deposition of these advanced protective coating systems to comply with increasingly harsh conditions in terms of thermo-cyclic loadings and corrosive environments. Especially columnar architectures which can be achieved e.g. by suspension plasma spraying (SPS) or plasma spray physical vapor deposition (PS-PVD) attract major interest as they offer high strain tolerance. The relation between process condition and microstructure will be outlined. In addition, results of thermal cycling of such columnar structured coatings will be shown and discussed. Improved capabilities to withstand increasing temperatures and harsh corrosive environments typically involve multi-layer designs with new material top-coats or composite inter-layers. Processing issues of TBCs with top-layers from high-temperature capable materials as e.g. pyrochlores, aluminates and complex perovskites will be reviewed. Degradation modes of those advanced coating systems under relevant test conditions are giving some indication for further improvements. Some remarks on TBCs on ceramic matrix composites will be given.


CH-3:IL02  Microstructural Evolution and Thermal Barrier Performance of Plasma-sprayed YSZ Coatings
KYEONG-HO BAIK, HEE-JIN PARK, SANG-WOON KANG, Department of Materials Science and Engineering, Chungnam National University, Yuseong, Daejeon, South Korea

In this study, the plasma-sprayed YSZ thermal barrier coatings from conventional powder and nano-structured powders have been evaluated in terms of microstructural features and thermal conductivities. The conventional YSZ coating was characterized by a splat quenched microstructure which contained a large amount of micro-defects including inter-splat pores and intra splat cracks. In contrast, the nano-structured YSZ coating formed a partially agglomerated nano-sized particle zone. Both YSZ coatings exhibited a similar trend in the relationship between porosity and thermal conductivity; the thermal conductivity of YSZ coatings decreased with increasing the amount of micro-defects. The thermal conductivity of the nano-structured YSZ coating was significantly lower than that of the conventional YSZ coating. Thermal barrier performance was evaluated by measuring the temperature difference between coating surface and substrate-coating interface, the nano-structured YSZ coating resulted in an improved thermal barrier performance, compared with conventional YSZ coating.


CH-3:IL03  Thermal Spray as an Additive/Layered Manufacturing Technology for Energy Related Applications
S. SAMPATH, Center for Thermal Spray Research, Stony Brook University, Stony Brook, NY, USA

Thermal spraying is a melt spray deposition process, in which particles in the diameter range of 1-100 microns are heated, melted, propelled and impacted onto a prepared substrate. A rapid sequence of events occurs: melting, spreading and rapid solidification, all taking place in microsecond timescales, enabling materials synthesis from extreme conditions. Coating is resultant from successive assemblage of microscale impacted droplets producing mesoscale thick films. Resultant deposits are defected, anisotropic, layered structures with concomitant implications on properties. The layered assembly also imparts gradients in through thickness residual stresses. These effects are in large part deemed “unintentional” and incorporated in many applications with limited manipulation. With advancements in understanding of process dynamics and the ability to control microstructures, a fresh opportunity is available to engineer and properties and functionalities through optimization of layered assembly. In this presentation, embodiments of such concepts will be shown using the interplay among coating architecture design, materials and manufacturing. Specific examples include novel multifunctional thermal barrier coatings, multifunctional coatings in fuel cells and thermoelectric devices. Illustrative examples of their applicability in industrial systems will also be highlighted.


CH-3:L04  Degradation of Zirconates and Novel Air-plasma-sprayed LaYbZr2O7 Thermal Barrier Coatings by Environmental Molten Salt and CMAS (CaO–MgO–Al2O3–SiO2)
MIN WANG, XINCHUN LAI; JUN YANG, SICONG GUO, ZIYUAN WANG, WEI PAN, Institute of Materials, China Academy of Engineering Physics; State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, China

Thermal barrier coatings (TBCs) are usually exposed to the attack of molten salt at working temperature due to the deposition of the environmental airborne sand/ash particles ingested by turbine engines. Therefore, the interaction of a series of advanced Air-plasma-sprayed (APS) free-standing TBCs including La2Zr2O7, Yb2Zr2O7 and LaYbZr2O7 with the molten sand dust collected in Beijing and molten simulated desert deposits was systematically investigated in the present research, both types of molten salt based on calcium–magnesium–alumino-silicates (CMAS). The Composition and structure of the interaction regions were characterized with XRF, TG-DTA, XRD, SEM, Raman and EDS, etc in details. It was found that APS La2Zr2O7, Yb2Zr2O7 and LaYbZr2O7 TBCs presented much better performance against the molten salt penetration compared with traditional APS 8wt% Y2O3-stabilized ZrO2 (8YSZ). In particular, Yb2Zr2O7 appears to be the optimum TBC material against molten salt attack. Furthermore, the penetration extent of molten sand-dust in Beijing is less than that of molten salt in simulated desert deposits. Possible mechanisms are discussed. It was found that the penetration depth of molten salt was related to the products of the interaction and the CaO content of the molten salt at 1200 °C.


CH-3:L05  Corrosive and Mechanical Properties of ZrO2 Thermal Barrier Coatings by Thermal Exposure
BYUNG-KOOG JANG¹, KOUICHI YASUDA², SEONGWON KIM³, YOON-SUK OH³, HYUNG-TAE KIM³, ¹Kyushu University, Kasuga-shi, Fukuoka, Japan; ²Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan; ³Engineering Ceramic Center, Korea Institute of Ceramic Engineering and Technology, Icheon, South Korea

Thermal barrier coatings (TBCs) have received a large attention because they increase the thermal efficiency of gas turbine engines by increasing the gas turbine inlet temperature and reducing the amount of cooling air required for the hot section components. To optimize TBCs for integration into gas turbines, characterization of the relationship between microstructure and thermal-mechanical properties of the coatings is necessary. The purpose of this work is to investigate the influence of the microstructure as well as porosity on mechanical properties of ZrO2-4mol%Y2O3 (YSZ) coatings deposited by air plasma spray (APS) or EB-PVD (electron beam-physical vapor deposition). The mechanical properties of plasma sprayed YSZ coatings were evaluated by three-point bending method. The bending strength, Young’s modulus and residual stress depend on microstructure as well as coating distance. TGO (thermally grown oxide) at interface of top and bond coat was generated after thermally cyclic test at 1100 °C. The hot corrosion between YSZ coatings and volcanic ash was examined by isothermal heating at 1200 °C in air between 10 min and 100hrs. The thickness of corrosive region at top surface of TBCs by the reaction between YSZ coating and volcanic ash was increased increasing the oxidation.


Session CH-4 - Tribological Thin Films and Coatings

CH-4:IL01  Self-Adaptive Mechanisms in Tribological Coatings Designed for Harsh Environment Applications
A.A. VOEVODIN, S. AOUADI, University of North Texas, Denton, TX, USA; C. MURATORE, University of Dayton, Dayton, OH, USA

Tribological coatings, which can re-arrange their structure and chemistry in a response to changes in environment humidity or temperature are of a practical importance for aerospace, tool, automotive, and other applications. Self-adaptive “chameleon” coatings made of hard nano-crystalline carbide, nitride and oxide matrices with addition of nano-inclusions of soft metals (Ag, Au), amorphous (MoS2, carbon) phases, and transition metals are capable for a formation of lubricating ternary oxides for lubrication over broad humidly (ambient to space) and temperatures (up to 1000 °C). The stored materials are released from nanophase reservoirs, facilitating tribo-contact chemistry and structure changes to continuously reduce friction and wear in harsh environments. Coating compositions are modified to guide tribofilm formations made of ternary oxides, where interlayered metallic and ionic bonding provides sliding friction reduction in the challenging mid-temperature regime of 500-700 °C. The nanocomposite “chameleon” structures are sandwiched between diffusion barrier nitride layers for extended operations and temperature cycling. Coating preparation, methods for in-situ characterization and identification of self-adaptation mechanisms in harsh environments are discussed.


CH-4:IL02  Self Adaption In Tribological Coatings
A. CAVALEIRO, F. FERNANDES, SEG-CEMMPRE, University of Coimbra and LED&Mat, Instituto Pedro Nunes, Coimbra, Portugal; T. POLCAR, FEL-CVUT, Czech Technical University, Prague, Czech Republic and nCATS, University of Southampton, UK

Tribological coatings are being increasingly used for improving the mechanical performance of components submitted to harsh conditions, particularly in increasing the wear resistance and decreasing the friction coefficient, for extending their lifetime, decreasing energy consumption and making environment greener thanks to the elimination of harmful lubricants. Hard and low friction coatings have been developed to satisfactorily accomplish such requirements; however, the increasing demands of industrial companies are creating new challenges whenever multifunctional properties are required to satisfy simultaneously loading conditions which are normally associated with antagonic materials behaviours. As friction and wear are typically surface materials properties, a potential solution can be to provide well known high performing coatings with additional functions achieved by in situ surface transformations induced by the sliding contact (self adaption). In this talk, we will show our proposal for solving the problems related with: (i) the lack of mechanical strength and the deficient behaviour in humid atmospheres of low friction coatings based on transition metal dichalcogenides (TMD); (ii) the decrease of the friction behaviour of hard coatings for high temperature application.


CH-4:L03  Tribological Properties of Hydrogenated W-C/ a-C:H Coatings in Different Environments
F. LOFAJ¹, D. MEDVED¹, M. KABATOVA¹, J. NOHAVA², J. DOBROVODSKY³, P. NOGA³, ¹Institute of Materials Research of SAS, Kosice, Slovakia; ²Anton Paar, Peseux, Switzerland; ³Advanced Technologies Research Institute, Faculty of Materials Science and Technology in Trnava, Slovak University of Technology in Bratislava, Trnava, Slovakia

Metal doped hydrogenated diamond-like carbon coatings exhibits wide range of mechanical and tribological properties strongly affected by the level of hydrogenation and environment, especially by humidity. The aim of the work is to investigate the effects of hydrogen originating from acetylene and hydrogen intentionally added into Ar atmosphere during reactive sputtering in the case of W-C/a-C:H coatings on their tribological properties in different environments involving humid air, dry nitrogen and vacuum. The studied coatings were prepared by conventional reactive magnetron sputtering as well as by reactive High Target Utilization Sputtering technique. The content of hydrogen in the coatings was measured by Rutherford Back Scattering combined with Elastic Recoil Detection Analysis. The results compare the influence of the addition of acetylene vs. hydrogen on the amount of hydrogen incorporated into the carbon matrix. These results are confronted with the obtained coefficients of friction in different environments.


CH-4:L04  Chemical Vapour Deposition of ZrN using insitu Produced ZrCl4 as a Precursor
E. RAUCHENWALD, R. HAUBNER, Institute of Chemical Technologies and Analytics, TU Wien, Vienna, Austria; M. LESSIAK, R. WEISSENBACHER, Boehlerit GmbH & Co. KG, Kapfenberg, Austria

Due to its good mechanical properties, ZrN can be considered a promising material for high performance coatings of various tools. ZrCl4 can easily be produced by the reaction of metallic Zirconium with HCl under elevated temperature and H2 as a carrier gas. In a following CVD reactor the ZrCl4 reacts with NH3 forming ZrN coatings. By varying the experimental conditions, such as H2 and NH3 gas flow, as well as addition of N2 to the reaction gas, we studied the influence of these parameters on coating thickness, surface morphology and crystal structure. Furthermore, the effects of various deposition temperatures in addition to positional differences of the hardmetal samples in the coating reactor were investigated. Ultimately, the generated samples were analyzed by calculation of coating thickness, microscopically determined properties as well as SEM, EDX and XRD measurements. With the obtained information about the effect of parameter changes on ZrN coatings future process designs can be facilitated.


CH-4:IL05  Wear Resistant Thermal Spray Coatings
G. BOLELLI, L. LUSVARGHI, T. MANFREDINI, P. PUDDU, V. TESTA, Università degli Studi di Modena e Reggio Emilia, Modena, Italy

Thermal spray coatings are widely used in applications where wear resistance is required. Thanks to thermal spray technologies versatility, many coating materials are available, from pure ceramic to metallic layers and hardmetal coatings. The aim of this talk is summing up the main properties and wear mechanisms of thermal spray coatings. In particular, the tribological response of the coatings, including friction behavior, will be analyzed according to the main wear processes, from sliding wear, to abrasion/erosion processes. The contribution of a corrosive environment will also be taken into account, trying to point out the severe consequences of a tribo-corrosive attack. All these phenomena will be discussed addressing the different coating materials, highlighting which coating system could provide the better protection according to various wear processes. This contribution aims to analyze both the materials science behind the wear damage and show case studies of thermal spray coatings applications in demanding and harsh environments. Besides, the main characterization techniques to evaluate wear rates and mechanisms will also be explained.


CH-4:IL06  Application and Limitations of Residual Stress Analysis in Wear Resistant Materials
M. WENZELBURGER, Federal-Mogul Powertrain, Federal-Mogul Friedberg GmbH, Friedberg, Germany

Chromium and chromium-ceramic composite (CKS) coatings deposited by galvanic plating are wear and corrosion resistant surfaces with high hardness and excellent tribological properties in suitable applications. Therefore, they play an important technological and economical role for many industries. During deposition at elevated temperatures and due to phase transformation processes, residual stresses arise that lead to the formation of microcracks in Cr or CKS platings. Due to the stepwise deposition of subsequent layers, residual stresses can be increased by superimposition. In the case of thin structures, deformations can occur. Residual stresses may also have an influence on the mechanical properties of coating and component, e.g. adhesive or tensile strength. This paper presents the residual stress analysis of Cr/CKS coatings on cast iron piston rings for large bore diesel applications. The influence of residual stresses on shape deviations is shown by comparison of finite element simulations and out-of-tolerance components as seen in production. For the measurement of residual stress-depth profiles, the hole drilling/milling method and XRD with layer removal are applied. Experimental results are described for samples and serial components with different coating thickness.


CH-4:L07  High Performance Ti(C,N)-Ni3Al Cermets and Coatings
K. PLUCKNETT, Z. MEMARRASHIDI, M. GAIER, W.A. SPARLING, T.L. STEWART, Dalhousie University, Halifax, NS, Canada

Ceramic-metal composites, or cermets, combine the favourable properties of both constituents and are widely used in demanding tribological and corrosive environments. The most commonly used cermet system, in both bulk and coating form, is based on tungsten carbide, typically with a cobalt binder (i.e. WC-Co). However, WC-Co suffers from a number of performance limitations, including high mass, poor corrosion resistance and severe property degradation at elevated temperatures. In the present work, cermet and coating systems based on either titanium carbide (TiC) or carbonitride (Ti(C,N)) ceramic phases are discussed, using various ductile nickel aluminide alloys as the binder. These materials have been assessed in terms of their fundamental mechanical behavior, sliding wear response and aqueous corrosion resistance. It is demonstrated that these cermets can offer comparable sliding wear resistance to WC-Co, combined with corrosion rates that are several orders of magnitude lower, while being roughly half the mass. Preliminary evaluation of high velocity oxy-fuel deposited coatings, based on these cermets, will also be discussed and compared with WC-Co.


CH-4:L08  Tribological Characterization of Mo-Cu-N, Mo-Cu-X(X=Cr, Ni, Si)-N Coatings Using Alloy Targets
KYOUNG IL MOON, HAN-CHAN LEE, Korea Institute of Industrial Technology, Gyeonggi-do, South South Korea

In this study, we tried to deposit Mo-Cu-N, Mo-Cu-X-N(X=Cr, Ni, Si) thin coatings showing high hardness and low friction at low and high temperatures to reduce energy consumption and wear problems in engine parts, aerospace and tools. In general, this kind of nanocomposite coating is made by various processes using multiple targets such as Mo, Cu and X(X= Cr, Ni, Si). However, it is difficult to control the exact composition, homogeneous deposition of large scale specimens during the deposition with multiple targets. We wanted to create the single Mo-Cu, Mo-Cu-X(X= Cr, Ni, Si) alloying targets with the composition showing the best friction coefficient and surface hardness. Single alloying targets with the composition showing the best properties were prepared by powder metallurgy methods, such as mechanical alloying and spark plasma sintering. Mo-Cu, Mo-Cu-X(X= Cr, Ni, Si) targets were prepared subsequently. The nanocomposite Mo-Cu, Mo-Cu-X(X= Cr, Ni, Si) coatings prepared using the alloying targets will be eventually compared with the films from the multiple targets.


Session CH-5 - Smart and Multifunctional Thin Films and Coatings

CH-5:IL01  Amorphous Alumina Tunable Barrier Films: An Integrated Process-local Coordination-properties Investigation
C. VAHLAS, D. SAMELOR, CIRIMAT, Toulouse, France; V. SAROU-KANIAN, P. FLORIAN, CEMHTI, Orléans, France; B. CAUSSAT, H. VERGNES, LGC, Toulouse, France

Amorphous alumina (a-Al2O3) films are processed by chemical vapor deposition (CVD) from aluminum tri-isopropoxide or dimethyl aluminum isopropoxide. Very high-field 27Al NMR reveals that, depending on process conditions, films may contain more than 40 at. % of 5-fold coordinated aluminum sites. The direct correlation between the local coordination of Al and the functional characteristics of the films are established. a-Al2O3 processed on 304L SS provide increasing corrosion protection from a 0.1 M NaCl solution at room temperature, as revealed by polarization curves and electrochemical impedance spectroscopy. They also provide pure Ti parts with excellent protection against oxygen ingress up to 600 °C. The oxidation kinetics of the a-Al2O3 coated Ti6242S alloy are 100 to 1000 times lower than the uncoated sample, while the mass gain after 80 cycles between the ambient and 600 °C of such coupons reveal no mass gain and no spallation, to be compared with a mass gain of 0.2 mg/cm2 for the uncoated alloy. Hydrothermal ageing of a-Al2O3 coated glass vials used in the pharmaceutics industry, results in the increase of the RMS roughness of the film surface from 17 to 61 nm and in the increase of the porosity, without affecting the adhesion of the coatings.


CH-5:IL02  Iron Boride Coatings for Wear and Corrosion Resistance Applications
E. MEDVEDOVSKI, Endurance Technologies, Inc., Calgary, Canada

Surface engineering is successfully employed to protect metallic components against wear and corrosion. Thermal diffusion process is one of the most prospective routes to protect large size complex-shape metallic components. The fundamental principles of this process are formulated and outlined for the formation of boride-based coatings. This process and coatings’ quality are defined by the boronizing batch composition, temperature and time, type of metallic substrate and its surface quality, and engineering process system design. The coatings with case depths up to 400 µm consisted of FeB and Fe2B (outer and inner layers, respectively) are uniform through the entire length of steel components and do not have spalling and delamination issues. The process – structure – properties relationship for the Fe-B coatings is outlined. The coatings’ application properties, e.g. abrasion, erosion, friction and corrosion resistance and, especially, resistance in the synergistic conditions are significantly higher than of bare steels and some other coatings used in industry. The iron boride-based coatings onto large-size complex-shape industrial components, e.g. tubing and casing with lengths up to 12 m with inner and outer surface protection, provide significant service life extension in harsh wear-corrosion environments in oil production, mineral processing and power generation.


CH-5:L03  How to Improve the Oxidation Resistance of Ultra-high Temperature Ta-C Coatings: An ab initio Guided Approach
H. RIEDL, T. GLECHNER, N. KOUTNA, T. WOJCIK, P.H. MAYRHOFER, Institute of Materials Science and Technology, TU Wien, Wien, Austria; S. KOLOZSVARI, Plansee Composite Materials GmbH, Lechbruck am See, Germany; D. HOLEC, Department Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Leoben, Austria; P. FELFER, Department of Materials Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany

In the sense of environmental sustainability, the application of ultra-stable material systems comes more and more into the focus of academia and industry. Ta-C is one of these highly attractive materials, exhibiting extreme thermal stability (≥ 3000 °C), highest hardness and strength, accompanied by strong chemical inertness. Nevertheless, a wide use of Ta-C is intriguingly limited by its unique covalent-metallic bonding character being responsible for the relatively low ductility and strong affinity to oxygen, leading to the formation of partly volatile oxides already in the range of 400 °C (representing 0.1·Tm). Therefore, we applied an ab initio guided approach (Density Functional Theory using VASP) to select alloying elements (X = Zr, Si, Al), which represents the best compromise between increased oxidation resistance, solubility in the preferred face-centred structure, as well as enhanced ductility (fracture toughness). In addition, the influence of carbon vacancies, which can be phase stabilizing in TMCs, is also consider. To verify our theoretical predictions, we deposited the most promising ternary Ta-X-C compounds by physical vapour deposition and oxidized the coatings up to 1600 °C. The kinetic of the oxide scale growth is investigated by HR-TEM, APT, as well as XRD.


CH-5:L04  HiPIMS Deposition of Ta-O-N Coatings for Water Splitting Application
J. CAPEK, S. BATKOVA, J. HOUSKA, R. CERSTVY, S. HAVIAR, Department of Physics and NTIS - European Centre of Excellence, University of West Bohemia, Plzen, Czech Republic; T. DUCHON, Department of Surface and Plasma Science, Charles University, Praha, Czech Republic

Ta-O-N is a very promising material for visible light water splitting into H2 and O2. However, it is still a big challenge to prepare Ta-O-N electrodes exhibiting efficient water splitting performance. In this work we first demonstrate that high-power impulse magnetron sputtering is a suitable technique for deposition of Ta-O-N coatings with a controllable oxygen to nitrogen ratio and thus their properties. The band gap width of the coatings can be tuned for an effective visible light absorption at preserved proper band gap alignment with respect to the water splitting reactions. Subsequently, we focus on an optimization of the structure of the coatings with respect to the transport of the generated electron-hole pairs. For this purpose, the Ta-O-N coatings were either prepared at an elevated substrate temperature or annealed in a vacuum furnace after the deposition. The carried out X-ray diffraction analyses indicate that the coatings prepared at the elevated temperatures consist of a mixture of oxides and/or nitrides, while the annealed coatings (with a proper O/N ratio) are characterized by a single TaON phase. Moreover, the resulting TaON phase can be highly textured when a proper seeding layer is used. This structure is very promising for the water splitting application.


CH-5:L05  Towards Understanding the Growth of Highly Epitaxial LaNiO3 Films from a Propionate-based Solution
R.B. MOS, M. NASUI, T. PETRISOR JR., M. GABOR, A. MESAROS, L. CIONTEA, T. PETRISOR, Center for Superconductivity, Spintronics and Surface Science, Technical University of Cluj-Napoca, Cluj-Napoca, Romania

LaNiO3 (LNO) has attracted much attention over the past few years as catalysts for fuel cells and for Li-O2 batteries. Nevertheless, due to its crystalline and electrical properties LNO is a promising material for the use as buffer layer for coated conductors. LNO has a perovskite structure with the lattice parameter of 3,84Å having a good lattice match with the Ni-based biaxially textured substrate and ceria or YSZ buffer layers. As consequence, it can be easily integrated in the conventional buffer layer architecture. This paper presents the results on the preparation of the precursor solution for the deposition of epitaxial LNO thin films by the chemical solution deposition method starting from lanthanum and nickel acetylacetonates. For a better understanding of the precursor chemistry, the thermal decomposition of the individual precursors was elucidated by corroborating the TG-DTA coupled with MS, XRD and FT-IR spectroscopy. Perovskite LNO films were deposited by spin-coating on STO(100) substrates and thermally treated between 600-900 oC. Highly oriented films with good out-of-plane and in plane textures were obtained. AFM and SEM analyses have shown smooth and crack-free surfaces. The temperature dependence of the resistivity of the LNO films is also presented.


CH-5:IL06  Photochromic Properties of Thin Films of Oxidized Yttrium Hydride
S.Zh. KARAZHANOV¹, J. MONTERO¹, D. MOLDAREV^{1, 2} , A. TABATABAEI³, E. MURAT BABA³, E. STRUGOVSHCHIKOV⁴, CH.CH. YOU¹, A. PISHTSHEV⁴, D. PRIMETZHOFER², H. PALONEN², M. WOLFF², E.O. ZAYIM³, E.S. MARSTEIN¹, ¹Department for Solar Energy, Institute for Energy Technology, Kjeller, Norway; ²Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden; ³Istanbul Technical University, Istanbul, Turkey; ⁴Institute of Physics, University of Tartu, Tartu, Estonia

In this presentation, the current status of the theoretical and experimental research related to understanding the deposition and characterization of the O-containing YHx films will be presented. The work has been performed in close cooperation of several Institutions. Deposition of the films has been performed by industrial magnetron sputtering machine on small and large area glass substrates at different Ar/H2 fluxes. Morphology has been characterized by scanning electron microscopy. Electrical, optical and structural properties have been characterized systematically. Compositional analysis has been performed by ion beam techniques such as Rutherford backscattering spectrometry (RBS), nuclear reaction analysis (NRA), elastic recoil detection analysis (ERDA). Connection between electrical and optical properties of the films and their composition has been established. We demonstrated that upon exposing into the excitation by light or by time-resolved X-ray beam the films show lattice contraction. By synchrotron measurements, possible location of oxygen atoms in the lattice has been established that have been correlated with theoretical studies by first-principles calculations. Mechanism of photochromic properties of the films has been suggested.


CH-5:IL07  Antifouling Coatings: Adhesion Mechanisms of Micro-organisms
C. TENDERO, CIRIMAT / INPT-ENSIACET, Toulouse, France

The smart monitoring of the environmental parameters and of their changes is strongly conditioned by the development of sensors that are able to operate continuously and autonomously, during several months. One of the major issues of this long-term in situ operation is the stress (e.g. biofouling, corrosion, erosion, bio-corrosion…) that the sensors undergo while immersed in the natural environment that disturb or even prevent the collection of high quality reliable data. Thus, sensors must be protected. This presentation deals with multifunctional coatings that protect the sensors from these various environmental stresses while ensuring full and reliable operation. It focuses on the antifouling property of the protective coatings, either anti-adhesive or bactericidal effect. The interaction between the coating surface and the adhesion mechanisms of the micro-organisms is particularly considered, especially during the early stages of the biofilm growth.


CH-5:IL08  Novel Ceramic and Layered Thin-film Materials for Contacts and Thermoelectric Applications
P. EKLUND, Energy Materials Group, Thin Film Physics Division, Dept. of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden

In this invited talk, I will present a brief overview with examples of our work on layered ceramics from experimental and theoretical investigations of oxide, nitride, and carbide thin film systems. Alloying approaches for thermoelectrics in CrN- and ScN-based systems are discussed [see review J. Mater Chem C 4, 3905 (2016)] as well as layered flexible oxide thermoelectrics [ACS Applied Materials & Interfaces 8 25308 (2017)]. Furthermore, I will discuss our results on Au- and Ir-based MAX phases [Nature Materials 16, 814 2017, see also review J. Phys. D. 50,113001 (2017)] of formation of Ti3AuC2 and Ti3Au2C2 phases with up to 31% lattice swelling by a substitutional solid-state reaction of Au into Ti3SiC2 single-crystal thin films with simultaneous out-diffusion of Si. These phases form Ohmic electrical contacts to SiC and remain stable after 1000 h of ageing at 600 °C in air.

 
CH-5:L09  Superhydrophilic Coatings: Study and Improvement of the Sol-Spray Fabrication of ZnO-Based Self-Cleaning Ceramic Surfaces
F.D. RODRIGUEZ-VILLALOBOS¹, J.J. RUIZ-VALDES¹, V. BARBIERI², C. SILIGARDI², E.I. CEDILLO-GONZALEZ¹, ¹Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, San Nicolás de los Garza, N.L., México; ²Università degli Studi di Modena e Reggio Emilia, Dipartimento di Ingegneria “Enzo Ferrari”, Modena, Italy

To solve some problems regarding the deterioration of facades and monuments exposed to pollution in outdoor environments, a methodology for an easy in-situ application of superhydrophilic (SHP) coatings was developed. The sol-spray (SP) technique was used to deposit ZnO nanorods in two stages on 5 different ceramic substrates, commonly used in the building sector. The effect of application temperature (60-100°C) and number of depositions (10-50) on the wettability and the photo-induced activity was also investigated by water contact angle (WCA) and stearic acid (SA) degradation respectively. All the tested samples shown photocatalytic activity vs SA under UV light. It was found that, depending of the substrate and applying up to 50 depositions, the ZnO nanorods coating promotes a decrease in the wettability of the final material. Additionally, treating the obtained material with UV light of 365 nm for 3 hours further decreases the WCA (<5°). In general, results showed that increasing temperature and the number of depositions favors the wettability of the material (10-15°). However, reducing the temperature and the number of depositions will facilitate the application of this technology to develop self-cleaning facades and monuments.


Session CH-6 - Modelling and Simulation of Coatings and Films

CH-6:IL01  Finite Element (FE) Modelling of Thermal Spray Coatings: Case Studies
G. BOLELLI, L. LUSVARGHI, T. MANFREDINI, P. PUDDU, V. TESTA, University of Modena and Reggio Emilia, Modena, Italy

Applications of thermo-mechanical finite element (FE) models to the study of thermal spray coatings and coating deposition processes are reviewed and illustrated. Two model types are presented: 1) Microstructure-based FE models, where meshes are created on 2D images of coating microstructures to perform “virtual” experiments by applying various load and boundary conditions. Applications range from the prediction of the elastic moduli of coatings, based on the “intrinsic” moduli of the constituent phases and on actual microstructures, up to the computation of entire stress-strain curves. It is also possible to study how properties change with varying microstructural features. More complex models can e.g. capture stress and strain distributions generated by a micro-scale sliding contact with a hard asperity, representing the fundamental tribological mechanism underlying a sliding wear condition. 2) Particle deposition models, which reproduce the deformation and spreading of individual particles sprayed onto an underlying surface in the solid or liquid (molten) state. Such phenomena cannot be observed experimentally, because of their excessively brief timescale. In all cases, possible applications are shown, current limitations and open research need are discussed.


CH-6:IL02  Multi-scale Modelling of Thin Films and Coatings for Scientific and Industrial Outcomes
H. RONKAINEN, A. LAUKKANEN, K. HOLMBERG, T. ANDERSSON, T. SUHONEN, VTT Technical Research Centre of Finland Ltd, Espoo, Finland

The multi-scale modelling provides valuable information on the stress, strain, and fracture phenomena generated in thin films and in thicker coatings. For the DLC and TiN films a novel multiscale numerical FEM model was developed integrating the layered and microstructural material features with the orientation of surface topography. In order to derive representative 3D topography of the coated surface a fractal geometry and surface voxelisation based approach were utilised. The simulations showed that the details of the main topographical orientation effect the local stresses that influence the wear performance. For the hard metal thermal spray coatings the factors, such as matrix properties and carbide volume fraction, play a significant role in mechanical performance, and a balance between these two attributes is necessary to provide excellent performance. The evaluation of novel Fe-based MMC coatings under sand abrasion and rock impact wear situations was performed with multiscale material modeling approach. Microstructural models were created to evaluate the damage mechanisms and tolerance, as well as the effect of microstructural features and properties on the wear resistance of the coatings. A good agreement the simulation results and experimental tests was found.


CH-6:IL03  Reactive Sputter Deposition Visualized by Modelling
D. DEPLA, K. STRIJCKMANS, R. SCHELFHOUT, Department of Solid State Sciences, Ghent University, Gent, Belgium

Magnetron sputtering is a mature technique for the deposition of thin films, both at laboratory and industrial level. Conceptually, the technique is quite simple and the process can be summarized in a few lines. But this apparent simplicity quickly vanishes, when one aims to model the process. The RSD model developed within the research group DRAFT reveals that reactive sputter deposition is a complex interplay between different physical and chemical processes. At the target, different processes influence the target condition as a function of the reactive gas flow. A detailed description of these processes, together with the strategies to get quantitative input parameters, will form the first part of the talk. In the second part of the talk, some modelling results for DC magnetron sputtering and HiPIMS will be used to visualize some key aspects of this technique. The authors hope that this talk will provide a good view on this technique, but we also hope that the talk will puzzle the attendees. Indeed, with the RSD model we aim, as mentioned by Samuel Karlin, for a model that not (only) fit the data, but also sharpen the questions.


Session CH-7 - Industrial Processing in Advanced Surface Technologies

CH-7:IL02  Scratch-resistant Transparent Sapphire Coating by Aerosol Deposition for Cover Glass Application of Smart Phone
JAE-HYUK PARK, DAE-GUN KIM, JONGWOO LIM, HYE-WON SEOK, MYUNG-NO LEE, BYUNG-KI KIM, IONES Co.,Ltd., Anseong-si, Gyeonggi-do, South Korea

In recent, advanced surface treatment process in mobile phone, automotive parts, and energy storage industry has been developed with various coating technology based on powder spray including aerosol deposition (AD), cold spray (CS), warm spray (WS), solution plasma spray (SPS) and so on. Since conventional thermal spray technologies are necessary to powder melting, these technologies make thermal shock during deposition and result in forming many cracks in ceramic coating. Moreover, cold spray technology may be still not suitable for ceramic coating process. The AD process enables ceramic materials to form highly dense coating at room temperature. In this study, we experimentally have certified a feasibility of the highly transparent and scratch-resistant sapphire (α-Al2O3) coating by aerosol deposition process for protecting surface damages on cover glass of smart phone owing to external impacts. The transmittance of the sapphire coating by fabricated AD process was more than 90% at visible range and acquired higher value than the transmittance of sapphire glass. Also, we found that crystallinity of sapphire coating is pure α-Al2O3 phase with nano-sized grains by TEM and XRD. In addition, we are investigating to provide several colors to the sapphire coating.


CH-7:IL04  Highly Ionized Deposition of Hard Coatings
H. GERDES, R. BANDORF, K. ORTNER, M. VERGÖHL, G. BRÄUER, Fraunhofer Institute for Surface Engineering and Thin Films IST, Braunschweig, Germany

Deposition of thin films with ions open up great advantages. The particle flux from the material source to deposited substrate can be influenced by electric and magnetic fields. Therefore, stray coating can be reduced and complex shaped surfaces can be coated depending on the pressure within the process. Within this contribution, different ways of generating highly ionized plasmas are covered. The most prominent is High Power Impulse Magnetron Sputtering (HIPIMS), with the seminal paper resulting in huge academic interest in 1999. Today HIPIMS is one of the industrial used coating technologies with increasing market share and relevance. Further technologies utilizing the high ionization are microwave and hollow cathode processes. In this presentation, these different deposition techniques are presented and results with respect to hard coatings are discussed. Both, plasma and film properties will be discussed. The ionization was monitored using optical emission spectroscopy. For the films, mechanical and tribological properties (hardness, coefficient of friction, wear) are presented.