Papers

ICMCTF2007 Session G2-1: Coatings and Automotive Applications

Thursday, April 26, 2007 1:30 PM in Room Royal Palm 4-6

Thursday Afternoon

Start	Invited?	Item
1:30 PM		G2-1-1 Coating Technology for the Automotive Industry, Present and Future H. Brändle (Oerlikon Balzers Coating AG, Liechtenstein) Vacuum based coatings for wear protection have found the entry into the automotive industry, starting with few but highly challenging applications. Since then, the evolution of materials, production technology and process know how have opened new application fields. Early approaches just involved coatings known from tool applications. Later the consideration of the specific industry demands led to even more suitable coating materials. This trend is still ongoing and important for the success of the technology. The latest material developments include multilayer systems and materials with specifically tailored properties, making them most appropriate for the offered application environment. The development of materials goes along with the required production technology, such as pre- and post-treatments and processing. The paper gives an overview of the current status of the production technology for PVD and PACVD coatings in the automotive industry as well as today’s market. An outlook will be given to future markets, technology trends, development processes and integrated production concepts.
2:10 PM		G2-1-3 Development of Advanced Coated Bearings X.B. Zhou, A. Sanz (SKF Engineering & Research Company, The Netherlands); S. Ioannides (SKF Engineering & Research Company, Netherlands) In the past 10 years, increasing demanding, government legislation, environmental concern and energy saving have put higher requirements on bearing performance under extreme conditions. Innovation on advanced coatings such as diamond like carbon have made it possible for bearing development to meet those requirements. SKF has been on the frontier to drive the development of the new technologies for bearing applications, in cooperation with worldwide top institutes and coating companies. In this paper, design of an advanced coating to meet specific requirements of a sliding bearing or a rolling bearing is addressed. Results on process development, testing and evaluation are reported.
2:50 PM		G2-1-6 Elastic and Plastic Deformation Behaviour of Diamond-Like Carbon Coatings J. Schaufler, K. Durst, M. Goeken (Friedrich Alexander University, Germany); O.K. Massler (Oerlikon Balzers Coating AG, Liechtenstein) Diamond like carbon (DLC) coatinsg are widely used in many industries. In highly loaded applications, the coating can be exposed to severe conditions, leading to deformation of the coating. The understanding of all aspects of elastic and plastic behaviour of DLC coatings can be crucial for the success of the application. In this work the local mechanical properties of Diamond-Like Carbon (DLC) coatings are investigated by nanoindentation and in-situ tensile tests. Technical surfaces contain growth defects, caused by singularities in the surface. The nanoindentation experiments are focused especially on the defect structure on DLC coatings, caused by the self picturing PECVD process. These growth defects show different elastic and plastic properties compared to the undefected areas. The failure behaviour under tensile loading of 3 micrometers thick DLC films deposited on both sides of 10 and 100 micrometers stainless steel foils is investigated by in-situ tensile tests. The in-situ investigations are made with a specific tensile test equipment in a scanning electron- and an atomic force microscope. The tests show detailed facts on damage formation in DLC coatings and especially the 10 micrometer steel/6 micrometer DLC system gives a clear view of the mechanical properties of DLC coatings under tensile strain. Based on the findings, conclusions are drawn for engine applications.
3:10 PM		G2-1-7 Enhancing the Performance of Automotive Components with Nanocomposite Tribological Coatings G.L. Doll, R.D. Evans (Timken Technology Center) This presentation summarizes the development, characterization, and performance of thin film, nanocomposite coatings on mechanical components for automotive applications to provide friction reduction, wear protection, and increased power density. In particular, nanocomposite materials consisting of nanocrystalline metal carbides and amorphous hydrocarbon matrices (MC/aC:H) have proven to be particularly beneficial as tribological coatings on mechanical components such as bearings, gears, valve train components, and fuel system components. Synthesis, characterization, tribological properties, and performance data of MC/aC:H coatings on precision steel components will be summarized.
3:50 PM		G2-1-9 The Development of Hydrogen-Free DLC-Coated Valve-Lifter Y. Yasuda, Y. Mabuchi, T. Hamada, H. Izumi (Nissan Motor Corporation, Japan) Due to its lower friction property, a hydrogen-free diamond-like carbon coating (DLC) obtained by an ionplating physical vapor deposition (PVD) process as an amorphous carbon film (a-C) was applied to an engine valve lifter to reduce mechanical losses. The effect of the a-C coating on reducing friction was evaluated with an engine motoring tester using actual engine parts. To meet the specifications of the valve lifter, a study was made of the typical topography of the a-C coating surface profile and the effect of the film thicknessagainst abrasive wear.
4:30 PM		G2-1-11 Super-Hard and EGR-Resistant Coatings for Advanced Diesel Engines K. Kazmanli, O. Keles, M. Urgen (Istanbul Technical University, Turkey); O.L. Eryilmaz, A. Erdemir, O.O. Ajayi (Argonne National Laboratory) Exhaust Gas Recirculation (EGR) is an effective technology for controlling NO_x emissions in diesel engines; however, it is harmful to the sliding surfaces of ring/liner assembly and other diesel engine components. Specifically, EGR causes heavy soot and particulate accumulations in lubricating oils and increases their total acid number (TAN) which in turn accelerates corrosion and wear. In this paper, we present the results of a systematic study focused on the development of EGR-resistant new materials and coatings. Specifically, we designed and developed a class of novel nanocomposite coatings that can drastically reduce friction and wear of sliding surfaces in EGR contaminated oils. These coatings are superhard (i.e., 35-60 GPa) and have strong affinity to react with additives in oils to form a protective boundary film that reduces friction and wear even under the harshest sliding conditions. These super-hard coatings are based on molybdenum nitride and copper, hence they are truly nano-composite and has the ability to restore lubricity, and to prevent corrosion and wear of critical engine components in advanced diesel engine applications. These coatings were able to lower friction and prevent wear in both the as received and highly acidified EGR contaminated diesel engine oils. The acidified oils were prepared by adding 0.5, 1, and 2 vol.% H₂SO₄ into the EGR contaminated oils. Even in such oils, the coated surfaces experienced very little wear and still maintained a reasonably low friction coefficient (0.03).
4:50 PM		G2-1-12 Successful Applications of Innovative PVD-CVD Technology in Machining, Forming and Automotive Industry A. Farinotti, C. Carini (Lafer Spa, Italy) In the last ten years a continuos development of thin film coatings allowed the final users to increase their productivity and reduce waste products with High Speed and Dry Machining operations. For these operations we will show how it has been possible to decrease significantly the cost/piece using tailored coatings and optimized cutting conditions, mentioning real production situations. Detailed examples will be given about the recoating of Solid Carbide Hobs, including an exclusive decoating technique for stripping Al-containing coatings from any substrate and preventing cobalt leaching or other chemical modifications on the metal surface. For forming and component industry a complete characterization of Superlattice CrN/NbN film will be shown, including a comparison to standard CrN regarding mechanical and tribological properties. Some interesting examples from the world of plastic forming and light alloys die-casting will be given; these applications are dominated by complex and simultaneous problems (such as corrosion, abrasive wear, demolding of the parts, quality of the surfaces) now successfully solved using coated moulds. Regarding components we will present some typical examples given the automotive industry where low friction, low roughness and high wear resistance are usually required; a last example will show the way of combining high mechanical efficiency with respect to the environment, using dump waste gases as fuels for cogeneration engines.
5:10 PM		G2-1-13 Functionality of Coatings in Automotive Applications O.K. Massler (Oerlikon Balzers Coating AG, Liechtenstein) The paper gives an overview over the materials employed in automotive coating applications, their properties and behaviour characteristics, as well as advanced requirements and approaches to meet them. Thin coatings have found their place in many areas of the automotive industry. Originally, the functions of the coatings, which have lead to their introduction into automotive applications were their resistance against adhesive and abrasive wear. The coatings used today are mainly carbon based materials, delivering an excellent wear resistance and low friction coefficent. Due to more and more complex requirement profiles, the design and extended behaviour fingerprint of the coating play a very important role for the anticipated performance enhancement. Besides the abrasive wear resistance and a low friction coefficient, fatigue resistance and other properties have become more important. Using a flexible process technology, the coatings can be modified and enhanced by producing multilayer structures and tailoring the topography to suit the severe demands of modern automotive industry. The paper shows examples and explains the underlying coating concepts for a variety of applications in engines.