Anirudha Sumant is a Materials Scientist at Center for Nanoscale Materials, Argonne National Laboratory and leading the research on nanocarbon materials including CVD-diamond, carbon nanotube, graphene as well as other 2D materials. The central theme of his research direction at CNM is on developing energy efficient systems based on nanocarbon materials. He has more than 22 years of research experience in the synthesis, characterization and developing applications of carbon based materials. His main research interests include electronic, mechanical and tribological properties of carbon based materials and other 2D materials, surface chemistry, micro/ nano-scale tribology, and micro-nanofabrication. He is the author and co-author of more than 120 peer reviewed journal publications, 2 book chapters, and has 22 granted patents, 15 pending. The list of his awards include four R&D 100 awards, NASA Tech Brief Magazine Award, three TechConnect National Innovation Awards, and Pinnacle of Education Award from Board of Governors of UChicago/Argonne LLC. He recently co-developed a nanotechnology educational kit “Next Gen STEM kit” for high school students in collaboration with United Scientific Supplies Inc. He has presented his research via numerous invited/keynote talks. His research in diamond materials helped in the formation of several start-up companies including NCD Technologies Inc. Bio-Oxidative Solutions Inc. He is a member of MRS, STLE and AVS.
Carsten Gachot received his PhD from the Saarland University in Germany in 2012 where he studied the effects of laser interference patterning on the microstructure and topography of metallic surfaces with a focus on tribological applications under Prof. Dr. Frank Mücklich and Prof. Dr. Martin H. Müser. For this work, Dr. Gachot was awarded by the European Honda initiation grant in 2011. Prof. Gachot was academic visitor at the tribology Group at the Imperial College London and is currently the head of the tribology research Group at the Vienna University of Technology. Additionally, Prof. Gachot is a visiting Professor at the Pontifical Catholic University in Santiago de Chile and chief editor of the peer reviewed journal “Industrial Lubrication and Tribology of the Emerald Publishing Group Leeds UK. His research interests include tribofilm formation in machine elements, materials tribology, surface engineering, wear processes, and contact mechanics at different length scales.
Gary Doll is the Timken Professor of Surface Engineering at the University of Akron. He holds a B.S. degree in Physics from the Marshall University and M.S. and PhD degrees from the University of Kentucky. He was also a postdoc at Massachusetts Institute of Technology. Before becoming a professor, Gary Doll developed a vast experience as a researcher on tribology and surface engineering in industry, in particular at The Timken Company and General Motors Research Laboratories. His main publications encompass the tribology of different coatings and surface modifications.
Jean Michel MARTIN is an Emeritus Professor at Ecole Centrale de Lyon (University of Lyon, France) since 2011. He obtained his PhD in 1978 from University of Lyon. He is an honorary member of the University Institute of France (IUF). He has more than 35 years of extensive experience in fundamental and applied research in tribology of thin films, diamond like coatings, boundary lubrication, antiwear and extreme-pressure additives, and surface analysis. He discovered superlubricity of pure MoS2 in ultrahigh vacuum and superlubricity of DLC coatings with OH-containing lubricants, implemented new additive formulations for metal forming and engine applications, and developed new analytical techniques for tribofilm analyses (XPS/AES/ToF-SIMS, XANES, etc.). He has published more than 160 papers in tribology, surface analysis and lubricant engineering and possessed 14 patents.
Towards Superlubricity under Mixed and Boundary Lubrication
Maria Isabel De Barros Bouchet is an Associate Professor in the Department of Science and Technology of Materials and Surfaces in the Ecole Centrale de Lyon in France. Her research activity in the Laboratory of Tribology and System Dynamics since 2001 mainly concerns the understanding of tribochemical reactions of lubrication additives using simulation by gas phase lubrication, the lubrication of carbon-based coatings with green additives and specially superlubricity mechanisms. Before her chair, she has made her PhD. on the PACVD deposition and characterization of diamond coatings for mechanical applications. Currently, her technological interests are in the synthesis and characterization of novel carbon materials for mechanical applications. Fundamentally, she is interested in understanding the role of structure and surface chemistry of carbon coatings on reactivity with the lubrication additives molecules used in lubricants and fuels. Her research presently includes investigation of the structure, mechanical and tribological properties of carbon coatings (DLC and diamond), and deposition processes of carbon thin films. She has over 65 publications with numerous citations on these topics, has collaborated to the redaction of 3 books and has 3 patents with industrial collaborators. She has served on Scientific Committee and chaired sessions for international conferences. She was the vice-chairwomen of the last event Tribo-Lyon congress 2013 and she serves as editorial board member for Lubricants 2018 Online Journal.
Friction Reduction Efficiency of Mo-based Additives: Booster Effect of Fatty Amines
University of Ljubljana, Faculty of Mechanical Engineering, Ljubljana, Slovenia
Dr. Kalin’s areas of research are wear and friction mechanisms of advanced materials, nanoscale interface phenomena, as well as boundary films for novel green lubrication technologies. He has published over 140 peer-reviewed journal papers, 10 book chapters, 2 books and holds 11 patents, including USA and EU patents. He has been active as a member of Editorial boards of 8 international journals, including Associate Editor of the ASME Journal of Tribology (2006-2012) and being founding Associate Editor of Frontiers in Mechanical Engineering – Tribology section (2018). Since 2012 he serves as the Editor-in-chief of Lubrication Science (Wiley). He has led over 35 large, typically 3-year projects, mostly international and colaborated with industrial partners in over 130 R&D projects. He has got several awards, including a prestigious ASME Burt L. Newkirk Award (2006), Fellow of STLE (2012), the two highest Slovenian state awards, namely Zois Prize (2006) and Zois Award (2015) and the Top 10 scientific achievements at University of Ljubljana (2014). Since 2017 he is a Deputy Chair of International Tribology Council that embraces tribology societies world-wide. Since 2010 he is the Head of the Laboratory for Tribology and Interface Nanotechnology and the Chair for Tribology and Maintenance Technology at University of Ljubljana. Since 2013 he acts as a coordinator of a joint European Master Programme on Tribology of surfaces and interfaces – TRIBOS, run in cooperation of four renown Universities sponsored by European Comission. In 2007-2011 he served as a Vice-dean for research and international affairs and in 2013-2017 as a Vice-dean for master and doctoral studies at the Faculty of Mechanical Engineering. Since 2017 he is a Dean of Faculty of Mechanical engineering.
SUBMICRON SCALE EXPERIMENTAL AND THEORETICAL INVESTIGATION OF THE MULTI-ASPERITY CONTACTS FOR REAL ENGINEERING SURFACES WITH VARIOUS TOPOGRAPHIC AND MATERIAL PROPERTIES
M. KALIN*, B. Brodnik Žugelj University of Ljubljana, Faculty of Mechanical Engineering, Ljubljana, Slovenia *firstname.lastname@example.org
Keywords: surface topography, material properties, experimental in-situ analyses, modelling, real contact area, asperity deformation.
In conventional engineering approach, contact conditions are typically calculated with the assumption of nominal contact area between two surfaces, which is greater than actual contact area. Consideration of such assumptions leads into calculations of milder contact conditions as they appear in real. Actual conditions within engineering contacts strongly depend on load, topographic parameters and material properties of contacting surfaces.
In this study we analysed how relevant engineering roughnesses (Ra = 0.1, 0.5 and 1.0 µm) and different materials (various steels, aluminium alloy and POM polymer) influence the actual behaviour of multi-asperity contacts in the full engineering loading range up to the material’s macro yield stress. Contact pressure, real contact area and deformation of the asperities were simultaneously measured experimentally in the newly developed test rig, which enables direct and in-situ investigation of the real contact area with submicron resolution.
The experimental results showed that the roughness strongly affects the deformation behaviour of the asperities and the real contact area that ranges from 10 to 20 % of nominal contact area at yield stress, depending on the roughness. Surprisingly, at the same Ra roughness and normalised pressure, metals exhibit quite similar type of contact behaviour despite the wide range of material properties covered in this study. On the other hand, polymer behaves very differently.
Moreover, the multi-asperity experimental results were also compared to the most common elastic-plastic statistical models to provide information that is seriously lacking today, especially at the sub-micron scale, which is studied in this work. Experimental results and the statistical models shows good agreement for the smoothest surface under all loads, while for rough surfaces and loads above ≈0.3∙Y the models overestimate the real contact area for several-times. It is shown that for the real engineering surfaces, the models applicability is expected in a loading range up to about 0.5·Y for smooth surfaces, but this limit decreases for rough surfaces.
Dr. Aswath has over twenty five years of experience in the area of processing of advanced materials that include monolithic and composite materials. In addition he has over 20 years of experience in the area of deformation, fatigue and fracture of specialty engineering materials. His work in the area of synthesis of materials involves the design of new materials using fundamental concepts in chemistry, thermodynamics and material science. His work initiaves include development of a new class of environmentally friendly high performance lubricant additives, development of biocompatible materials for applications ranging from structural orthopedic, tissue regeneration and drug delivery applications, and development of sustainable concrete for structural and transportation applications. In the past he has been involved in the development and evaluation of a new generation of titanium aluminides for jet engine applications. He has also worked extensively in synthesis, phase transformations and mechanical properties of in-situ Si3N4 reinforced barium aluminosilicate. He has worked on research projects with many industrial partners and with faculty in Ohio State University, Brown University, University of Trento, Ecole Centrale de Lyon and Indian Institute of Science among others.
Role of Tribofilms in Engine Tribology…How 100 nm makes all the difference