Bericht 46 Tribologie + Schmierungstechnik · 69. Jahrgang · eOnly Sonderausgabe 2/ 2022 Abstract The 23 rd International Colloquium Tribology in January 2022 was held for the first time as an online conference only, with about 300 participants. The organising team, speakers and participants therefore made the best of this traditional event in Germany in view of the Covid-19 pandemic, even though the “online conference is not a substitute for a conference on site”, as one participant stated aptly. In almost 140 talks, 8 of which were plenary talks, new findings were reported on the topics of lubricants and additives, measuring techniques, digitalisation, coatings and surfaces, transport and industry, and sustainability. Several presentations were dedicated to the EU project “i-Tribomat”, which will soon be launched as “The European Tribology Centre” that offers services for the tribological characterisation of materials and lubricants. Virtual event for the first time While 2020 was mainly characterised by cancellations of face-to-face conferences due to the outbreak of the Covid-19 pandemic, organisers moved to set up online conferences from 2021 on. We have also seen the emergence of webinars and YouTube channels to provide scientists with specific knowledge in tribology and to enable the exchange of new knowledge, such as Web Seminar Series on Tribology (WeSST) [1] and from SKF Group [2] to name a few. The Technische Akademie Esslingen (TAE) made considerable efforts to enable a smooth running of an online conference. Eventually, the 23 rd International Colloquium Tribology took place for the first time as a completely virtual event in January 2022. The conference covered 3 days with more than 300 attendees and about 140 contributions provided in 6 parallel live streams (see Figure 1). Needless to say, that such an event required a lot of organisational talent and technical support comprising the upload of the programme, speaker list and attendee data to a brand-new platform that was established in just 6 weeks. Issues that arose before and during the event were fixed in a competent and calm manner, just as we have come to appreciate from the TAE team during face-to-face conferences. Plenary talks The 8 plenary talks reflected the versatility of tribology by its nature as well as developments in view of global trends, among others electrification, sustainability, and digitisation. Review of the 23 rd International Colloquium Tribology - 25-27 January 2022 Nicole Dörr, Andreas Pauschitz* * Nicole Dörr Andreas Pauschitz AC2T research GmbH, Viktor-Kaplan-Straße 2/ C, 2700 Wiener Neustadt, Austria Figure 1: Screenshot of the virtual participant’s view showing the plenary talk of Lutz Lindemann, Fuchs Petrolub SE on 25 January 2022 (with permission of Technische Akademie Esslingen, 2022) DOI 10.24053/ TuS-2022-0037 Bericht 47 Tribologie + Schmierungstechnik · 69. Jahrgang · eOnly Sonderausgabe 2/ 2022 On the first conference day, Lutz Lindemann from Fuchs Petrolub SE has provided an overview of the global lubricant market in a proven manner, at this conference with a focus on e-mobility and raw materials. Exemplarily, the increasing use of electrical vehicles will heavily change the petrochemical (refinery) landscape. In view of changes in the world order (from global to regional), circular economy and sustainable raw materials, Lindemann emphasised on the importance of a shift in a coordinated way. Inga Herrmann from VSI Verband Schmierstoff-Industrie e.V. provided valuable insight into the dimensions of sustainability, i.e., ecology, economy and social. Interesting detail was that by far the largest portion of the CO 2 footprint is done before the lubricant industry comes into play. Herrmann therefore highlighted the cradle-to-grave approach that leads to the product carbon footprint (PCF). It covers the total greenhouse gas emissions of a product from the extraction of the raw materials to the product’s end-of-life, i.e., waste treatment, recycling, or reuse. The second plenary session was opened by Volker Weihnacht from Fraunhofer Institut für Werkstoff- und Strahltechnik (IWS) who reported on vacuum tribology of superhard ta-C coatings. Unidirectional ball-on-disc experiments in vacuum of ta-C against various materials revealed good friction and wear properties when brass and aluminium oxide were used for the counter-bodies. Pairings of ta-C: X against steel offer slight advantages with Band Si-doping. Susanne Beyer-Faiß, CEO of Dr. Tillwich GmbH Werner Stehr, presented a holistic approach of using ionic liquids both in polymers and lubricants to achieve electrical conductivity in radial plain bearings for reliable electrical discharge. The combination of ionic liquid, graphene and carbon nanotubes significantly improved electrical properties of a plain bearing made of PA66 running against a steel shaft. In view of the vast results of the study, 2 more presentations were given focusing on a new apparatus to simulate lubricant ageing under current flow and modern evaluation methods of tribotest results, respectively. Franz Pirker from AC2T research GmbH provided an update on the EU project “i-TRIBOMAT” [3] dealing with the establishment of an open test bed for materials tribological characterisation. This one-stop shop for tribological characterisation will be operated by partners from all over Europe, which is dedicated to validating and up-scaling new materials. 6 more individual presentations were brought to “i-TRIBOMAT” illustrating digital tribological services together with 2 use cases related to friction control by surface texturing and novel journal bearing materials. The third plenary session was held as the closing session and was a dignified conclusion of the 23 rd International Colloquium Tribology. Steffen Glänzer from Clariant shared the findings of a benchmark of polyglycols (PAG) of various chemical structures against a polyalphaolefin (PAO) for the use in electrical vehicle drivetrains. Lower friction than with PAO could be demonstrated in a unidirectional pin-on-disc contact. Energy efficiency was further stated by a low viscosity of 3-4 mm 2 / s at 100 °C. Most crucial for electrical vehicles is thermal management in the battery and powertrain. Here, better performance of some PAG than the chosen PAO was shown expressed by higher Mouromtseff numbers as indicator for heat transfer by a fluid. Ken Hope from Chevron Phillips Chemical Company, STLE President 2021-2022, provided details on the perspective of STLE regarding emerging trends and lubrication challenges currently arising from them. The report is based on a global survey of tribologists and lubrication engineers in 2020 [4]. 20 interviews with experts and 591 members from 48 countries participated in the survey to evaluate the effects of new technologies in the application sectors transportation, energy, manufacturing, and medical & health. As to transportation, electric vehicles, fuel cells and autonomous driving are considered the drivers of the anticipated changes of the future. Regarding energy, wind and solar energy have been predicted as the major game changers in terms of clean energy, provided that progress goes hand in hand with advances in energy storage. Concerning manufacturing, it was found that electric vehicles and additive manufacturing (3D printing) will cause a significant decline in metalworking and thus the use of metalworking fluids. In medical & health, 3D printing was deemed to have potential to produce customised tissues and prosthetics. Denis Mazuyer from Ecole Centrale de Lyon concluded the conference’s talks by showing an innovative approach to reduce friction in transport from hydrodynamics to boundary regime, based on the IMOTEP research platform. This platform allows for the investigation of lubrication mechanisms over 11 orders of magnitude of sliding velocity and 3 orders of magnitude of contact pressure. Mazuyer’s approach was illustrated by a number of fundamental experiments with a polymer additive in a base oil spanning the range from boundary via elastohydrodynamic to hydrodynamic lubrication regime. Scientific contributions in parallel sessions 129 talks were organised in 8 main topics and presented during 6 parallel sessions, i.e., parallel live streams (see Table 1). As expected, topics concerning lubricants and lubrication dominated the conference. It is impossible to adequately address all the presentations. Therefore, some highlights from the multitude of talks and topics are discussed in the following. In trends in lubricants and additives, Kevin Duncan from Croda Europe Ltd. has proposed liquid amines as novel high-performance base oils. Dominic Linsler from Fraunhofer IWM showed that reversible tuning of viscosity using UV light can be realised by functionalisation of polydimethylsiloxane with anthracene groups. As to stability and lifetime behaviour of lubricants, a number of talks have reported on laboratory and engine bench tests to account for the operating conditions lubricants are exposed to in the field, e.g., Markus Grebe from Hochschule Mannheim on grease thickener degradation and Markus Matzke from Robert Bosch GmbH on antioxidants in greases. Talks on grease components formulation showed a focus on applications in electrical vehicles, e.g., low viscosity low volatility (LVLV) PAO base oil for bearing grease presented by Sven Meinhardt from Exxon-Mobil Chemical Central Europe. Automotive lubricants were mainly represented by engine oils and fuel economy, e.g., with a floating liner single-cylinder engine tests as demonstrated by Abdullah Alenezi from University of Leeds. White etching layers (WEC) on industrial machine elements, especially wind turbines, were addressed in a couple of talks. Daniel Cornel from RWTH Aachen illustrated the impact of lubricant formulation on WEC formation under sliding, mixed friction and current passage conditions. Although electric vehicles are pushed by technological and legal means (European Green Deal), reports on advances have remained moderate at this year‘s International Colloquium Tribology. The focus was on reports on efficiency increases through suitable synthetic base oils as well as defoamers and polymers to improve functio- Bericht 48 Tribologie + Schmierungstechnik · 69. Jahrgang · eOnly Sonderausgabe 2/ 2022 Table 1: Overview of topics, sub-topics and corresponding number of talks DOI 10.24053/ TuS-2022-0037 Bericht 49 Tribologie + Schmierungstechnik · 69. Jahrgang · eOnly Sonderausgabe 2/ 2022 DOI 10.24053/ TuS-2022-0037 nality, e.g., polymeric additives presented by Dmitry Shakhvorostov from Evonik Operations GmbH. Fewer than 10 talks on this topic were contrasted with more than 20 presentations at the STLE‘s 76 th Annual Meeting & Exhibition in May 2022. In view of the recently announced EU phase-out of vehicles with internal combustion engine by 2035, it can be expected that significantly more R&D work in the field of e-mobility will be reported in the future. This is also in line with the results of the survey conducted after the 23 rd International Colloquium Tribology, according to which the topic of e-mobility was seen as essential for the next conference, alongside sustainability, lubricants based on recycled materials, CO 2 footprint, and green tribology. Several aspects were related to sustainable lubrication, among others: Sustainability by design criteria using tribology and lifecycle assessment as proposed by Amaya Igartua from Fundación TEKNIKER and novel bio-based base oils as presented by Arthur Coen from Oleon NV. One aspect in coatings, surfaces and underlying mechanisms was materials tribology. Julia Rau from KIT provided insight into tribo-oxidation of high-purity copper the mechanism of which was revealed by use of an atom probe. Another presentation from KIT given by Carina Morstein was about the humidity influence on graphite lubrication. Structural changes of graphite in the wear scar were elucidated by transmission emission microscopy (TEM) and electron energy loss spectroscopy (EELS). Digitisation in tribology covered traditional topics such as modelling and simulation of rolling and sliding contacts as well as molecular dynamics of additive adsorption on surfaces and viscosity modifiers in oil. Stefan Mitterer from Oilcheck GmbH explained how digitisation can support lubricant analysis. Shin Ho Kim Lee from CIB Margarita Salas reported on the use of artificial intelligence tools for the design of new dispersants. In test methodologies and measurement technologies, well known tribometer manufacturers reported on use cases of tribometry: Dirk Drees from Falex Tribology on optimization of testing, Matthew Smeeth from PCS Instruments on mini-traction machine (MTM) rig for wear testing, Ameneh Schneider from Optimol Instruments Prüftechnik on material compatibility, among others. Continuous wear measurement by radioactive tracers was presented by Peter Lee from Southwest Research Institute and Manuel Zellhofer from AC2T research GmbH, the latter for diamond-like carbon (DLC) coatings. Heat maps for visualizing friction coefficient curves were presented many times at this conference. In this way, the friction coefficient of the entire tribometric experiment can be displayed and evaluated, i.e., for each cycle, for each position along the wear track and the friction coefficient level displayed in false colours. This method of visualisation will certainly become common in tribology. Exhibitions The general and unfortunately disappointing resume of the exhibitors was that there was little interaction with the conference participants. Apparently, there is still too much reluctance to make an enquiry via an online tool than to start a conversation with a spontaneous question while walking through the exhibition. Attendance A total of about 300 people participated in the conference. Presenters and “only” participants were about 150 each. As expected, Germany accounted for the largest share of attendance, at around 40 %. The conference provided a platform for participants from all over Europe as well as the United States, Japan, India, China, Korea, and Mexico. Countries represented with about 10 % each of the attendees were United Kingdom and France. Austria, Spain, Sweden and the United States were represented by about 5 % of the attendees each. Closing remarks The pandemic undoubtedly pushed the use of online communication tools both in our daily professional life and conference activities. It has become common to record the presentations and make them available as videos on demand. Besides the availability of the videos on the TAE’s event platform, participants were able to contact speakers, exhibitors, and other participants directly via the platform after the conference for 3 months. In view of the number of parallel sessions, making it impossible to listen to all presentations of interest, videos on demand can complement the offer of face-to-face conferences. This way, networking to establish new contacts and maintain existing ones can be intensified. Indeed, personal discussions with conference participants form the backbone of conferences together with presentations and exhibitions. Virtual events will certainly permanently complement our means of information exchange. In addition, we are able to optimize our business-driven travels, or more precisely, reduce them. However, that is what we also learned in the past 2 years, talking face-toface to someone cannot be replaced (yet) by modern technology. The Steering Committee of the conference, Ksenija Topolovec-Miklozic and Andreas Pauschitz, would like to express their sincere thanks to all presenters, exhibitors, participants, program committee members, and of cour- Bericht 50 Tribologie + Schmierungstechnik · 69. Jahrgang · eOnly Sonderausgabe 2/ 2022 se the organisational and technical team at TAE, all of them have made this virtual event possible. We look forward to seeing you again - in person - at the 24 th International Colloquium Tribology in January 2024. References [1] Web Seminar Series on Tribology (WeSST), YouTube Channel, https: / / www.youtube.com/ channel/ UCN0Jlz Er-iPAcWNb2JBnwMw, accessed 31 October 2022 [2] SKF Stronger, YouTube Channel, https: / / bit.ly/ SKF stronger_playlist, accessed 31 October 2022 [3] i-TRIBOMAT - THE European Tribology Centre, http: / / i-tribomat.com/ project.html, accessed 31 October 2022 [4] STLE 2020 Report on Emerging Issues and Trends in Tribology and Lubrication Engineering, White Papers in Technical Library, https: / / www.stle.org/ files/ , accessed 31 October 2022 Acknowlegdement This review was supported by the Austrian COMET Program (project InTribology1, FFG no. 872176). DOI 10.24053/ TuS-2022-0037