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  • 1.
    Ekman, Jonas
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Antti, Marta-Lena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Törlind, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Kuhn, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Nilsson, Hans
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Öhrwall Rönnbäck, Anna
    Gustafsson, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Zorzano Mier, María-Paz
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Milz, Mathias
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Parida, Vinit
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Behar, Etienne
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Wolf, Veronika
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Dordlofva, Christo
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Mendaza de Cal, Maria Teresa
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Jamali, Maryam
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Roos, Tobias
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Ottemark, Rikard
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Nieto, Chris
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Soria Salinas, Álvaro Tomás
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Vázquez Martín, Sandra
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Nyberg, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Neikter, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Lindwall, Angelica
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Fakhardji, Wissam
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Projekt: Rymdforskarskolan2015Other (Other (popular science, discussion, etc.))
    Abstract [en]

    The Graduate School of Space Technology

  • 2.
    Hansen, Jonny
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Björling, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Nyberg, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Larsson, Roland
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Elastohydrodynamic performance of a hydrocarbon mimicking ionic liquid additive2017Conference paper (Refereed)
    Abstract [en]

    Machine elements operating under lubricated conditions will eventually fail due to high stresses and fatigue-related causes. In order to find optimum protective measures, it is important to understand how the stresses arise and what factors that influence their magnitude. With the current shift for more sever lubricating regimes, the role of tribo-improvers is becoming vital. At this point, the interplay between the chemisorption mechanism of various lubricant compounds and surface failure is not yet fully understood. To obtain a better understanding of this, a newly developed ionic structured tribo-improving additive, based on silicon, was investigated and benchmarked against conventional heavy-duty gearbox additives. A ball on disc device was operated under heavily loaded rolling/sliding conditions, at elevated temperature to simulate gear like conditions, and lubricating performance was subsequently evaluated in terms of friction and wear. Such results highlight the importance of properly designed lubricants for optimal tribo-performance under rolling-sliding conditions

  • 3.
    Nyberg, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Ionic liquids as lubricants for mechanical devices on Mars2017Conference paper (Other academic)
  • 4.
    Nyberg, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lubrication mechanism of hydrocarbon-mimicking ionic liquids2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Lubrication is critical in order to achieve high efficiency and reliability of machine elements such as gears, bearings, and other moving mechanical assemblies (MMA). In space applications, tribological properties of lubricants are quickly growing more important. Traditional space systems such as satellites imply MMA such as gyroscopes, antenna pointing mechanisms, and solar array drives. These MMA operate in high vacuum (<10-5 Pa) under lightly loaded conditions. Modern space missions on the other hand, such as remotely operated vehicles used for in-situ Mars exploration relies on different types of MMA. In these robotic systems, electromechanical actuators are being used extensively to provide controlled motion. Gears and bearings in these actuators operate in an atmosphere mainly consisting of CO2 at ~10+3 Pa under heavily loaded contact conditions. In these conditions, the tribosystem is likely to operate in the boundary lubricated regime, with consequent risk of high friction and wear.

    High molecular weight fluids have significant heritage in space because of their low vapor pressure. They are currently employed as lubricants in a wide range of space applications, as they meet high demands on resistance to vacuum outgassing. Unfortunately, the large molecules are susceptible to degradation under heavy load.

    Ionic liquids (ILs) on the other hand, are synthetic fluids that consist entirely of ion pairs with opposing charge. The resulting ion bonds enable inherently low vapor pressure of the fluid without the need for a high molecular weight. For this reason ILs have been advocated as potential lubricants for space applications, but so far compatibility issues have hampered their use as lubricants. Countless IL variations are possible, and solutions are thus likely to exist. Constituent ions can be designed individually and combined in various configurations. However, the fundamental understanding of the lubricating mechanism of ionic liquids is still incomplete, and consequently the optimum molecular structure for IL lubricants remain unknown.

    In this thesis, a stepwise approach to molecular design of IL lubricants is described, and the resulting hydrocarbon-mimicking ionic liquids are evaluated in tribological experiments. In this thesis, the experiments focus on tribological performance, using steel-steel tribopairs in air environment under boundary lubrication (Paper I). Boundary film formation under a range of contact pressures and temperatures, is analyzed after tribotesting by optical profilometry, scanning electron microscopy (SEM), and energy dispersive X- iii ray spectroscopy (EDS) in Paper II. The analysis reveal formation of a highly effective boundary film based on silicate, that can be further enhanced by amine additives. This thesis demonstrates the feasibility of improving tribological performance of ionic liquids by molecular design.

  • 5.
    Nyberg, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Dörr, Nicole
    AC2T Research GmbH, Wiener-Neustadt, Austria.
    Igartua, Amaya
    IK4-Tekniker, Eibar, Spain.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Additive Technology for Halogen-free Room Temperature Ionic Liquids2016In: STLE 2016 Annual Meeting and Exhibition, 2016, Las Vegas, NV, USA, 2016Conference paper (Refereed)
    Abstract [en]

    Room temperature ionic liquids (RTIL) are increasingly being studied as advanced lubricants due to inherent properties such as thermal stability, low volatility, and non-flammability. While traditional lubricants are being optimized by additive technology, researched RTILs have generally been additive-free due to a lack of miscible additives. Recently, new RTILs have been designed for improved solvency of synthetic lubricant additives. In this work, RTIL samples based on tetralkylphosphonium cations have been evaluated. They are halogen-free and hydrophobic to minimize corrosion. Five RTILs were evaluated in a steel-steel tribotest where the results showed excellent tribological performance for RTILs with friction modifying and anti-wear additives designed for synthetic lubricants. These novel RTILs combined with additives demonstrate high potential as advanced lubricants due to their persistent nature in combination with excellent tribological performance.  

  • 6.
    Nyberg, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Dörr, Nicole
    AC2T Research GmbH, Wiener-Neustadt, Austria.
    Igartua, Amaya
    IK4-Tekniker, Eibar, Spain.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Improvement in the Tribological Performance of Room Temperature Ionic Liquids by Additive Technology2016In: Nordic Symposium on Tribology - NORDTRIB 2016, Hämeenlinna, Finland, 2016Conference paper (Refereed)
    Abstract [en]

    Room temperature ionic liquids (RTILs) have interesting properties such as thermal stability, low volatility, and non-flammability. Most research on RTIL lubricants regard RTILs composed of fluorine-containing anions. In metal-metal contacts, these fluids form boundary films of iron fluoride which reduces friction and wear to some extent, but on the other hand cause corrosion under humid conditions. Additives are one way of improving RTIL performance, however; most additives are designed for conventional petroleum base oils, and are therefore hardly miscible with RTILs. In order to improve the performance of RTILs, halogen-free and additive compatible RTILs have recently been developed as potential base oils for advanced lubricants. In this work, RTILs based on phosphonium cations and silylalkyl-sulfonate anions have been evaluated. These fluids are halogen-free and hydrophobic, showing good results in Cu-corrosion testing. Five RTILs, prepared from different anion-cation combinations, were evaluated in steel-steel tribotest. Compared as neat fluids, the RTILs performed superior to perfluoropolyether (PFPE) -based reference lubricant in terms of wear and friction reduction. In the attached figure, it can be seen that the mean friction coefficient is significantly lower for the neat RTIL samples at both 100 and 150 N. Regarding wear volume; the results show that the investigated RTILs produce better protection against wear and are robust to increased load. The tribological performance of RTILs is further improved when adding friction modifying and anti-wear agents designed for synthetic lubricants. This excellent tribological performance, in combination with the inherently persistent nature of ionic liquids demonstrates the high potential as advanced lubricants for these novel RTILs.

  • 7.
    Nyberg, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Additives to Improve Tribological Properties of Ionic Liquid as Base Fluids2017Conference paper (Refereed)
    Abstract [en]

    Room temperature ionic liquids (RTILs) have several properties which make them interesting candidates as base fluids for extreme conditions. However, a lack of compatibility with tribo-improving additives combined with an often overly aggressive nature is limiting their use as base fluids. To overcome these drawbacks, hydrocarbon-imitating RTIL base fluids have recently been developed. These lubricants aim for a more balanced interaction with metal surfaces while enabling compatibility with common additives, so that the reactivity with the lubricated surface can be tuned in a manner similar to hydrocarbon base oil–additive systems. In this work, the effects of several common additives in the novel RTIL were examined by laboratory tribotesting. Surface analysis was performed in order to study the lubrication mechanisms.

  • 8.
    Nyberg, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Boundary Film Formation from Hydrocarbon-mimicking Ionic Liquids2017Conference paper (Refereed)
    Abstract [en]

    Ionic liquids have properties that are very useful in high performance lubricants. However, they must be well tuned to the tribological system. Hydrocarbon-mimicking ionic liquids have been developed in an effort to overcome some of the compatibility problems that are holding back the use of ionic liquids in tribology. In this work, hydrocarbon-mimicking ionic liquids are evaluated as base fluids in steel-steel reciprocating tribotests. Wear and friction reducing boundary films are formed and found to be composed mainly of Si and O. An amine additive is found to stimulate the formation of this boundary film.

  • 9.
    Nyberg, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Mouzon, Johanne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Formation of Boundary Film from Ionic Liquids Enhanced by Additives2017In: Applied Sciences, E-ISSN 2076-3417, Vol. 7, no 5, article id 433Article in journal (Refereed)
    Abstract [en]

    Room temperature ionic liquids (RTILs) have several properties that make them interesting candidates as base fluids for extreme conditions. However, a lack of compatibility with tribo-improving additives combined with an often overly aggressive nature is limiting their use as base fluids. To overcome these drawbacks, hydrocarbon-imitating RTIL base fluids have recently been developed. In this study, the effects of several common additives in the novel RTIL (P-SiSO) were examined by laboratory tribotesting. A reciprocating steel-steel ball-on-flat setup in an air atmosphere was used, where the lubricant performance was evaluated over a range of loads and temperatures. Surface analyses after testing were carried out using optical profilometry, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Neat P-SiSO displayed high performance in the tribotests. At an elevated load and temperature, a shift in lubrication mode was observed with an accompanying increase in friction and wear. Surface analysis revealed a boundary film rich in Si and O in the primary lubrication mode, while P was detected after a shift to the secondary lubrication mode. An amine additive was effective in reducing wear and friction under harsh conditions. The amine was determined to increase formation of the protective Si–O film, presumably by enhancing the anion activity.

  • 10.
    Nyberg, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Respatiningsih, Catur
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Molecular design of advanced lubricant base fluids: hydrocarbon-mimicking ionic liquids2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 11, p. 6364-6373Article in journal (Refereed)
    Abstract [en]

    This paper describes the molecular design and tribological evaluation of novel room-temperature ionic liquid (RTIL) lubricants{,} abbreviated as P-SiSOs. The RTILs are designed to mimic hydrocarbons{,} in order to ensure their compatibility with existing tribosystems as well as enable use of conventional additives. Steel-on-steel ball-on-flat reciprocating tribotests performed under atmospheric conditions show that the neat P-SiSOs exhibit favorable performances{,} resulting in friction and wear significantly lower than those in the case of the perfluoropolyether lubricants used as references. Tribotests performed at elevated loads and temperatures indicate the formation of friction-reducing boundary films of the neat P-SiSOs. The tribological performance of the P-SiSO is improved further by the incorporation of additives conventionally used in hydrocarbon oils. When used in a concentration of 5 wt%{,} the additives glycerol monooleate{,} dibenzyl disulfide{,} and oleylamine improve the tribological characteristics of P-SiSO. These results indicate that molecular-designed hydrocarbon-mimicking RTIL lubricants can exhibit suitable performances in the neat form and that their performances can be improved further by using conventional additives{,} as in the case of hydrocarbon base oil-additive systems.

  • 11.
    Nyberg, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Tomastik, Christian
    AC2T Research GmbH, Wiener-Neustadt, Austria.
    Dörr, Nicole
    AC2T Research GmbH, Wiener-Neustadt, Austria.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Boundary Film Formation of P-SiSO in Reduced Oxygen Atmosphere2018In: NORDTRIB 2018, Uppsala, 2018Conference paper (Refereed)
    Abstract [en]

    Modern space exploration missions, such as planetary exploration of Mars, have significantly different tribological concerns compared to conditions faced by mechanical devices in satellites. Space lubricants have traditionally implied extremely low vapor pressure, but limited performance in boundary lubrication. Mars devices on the other hand are subjected to heavier loads, while operating in an atmosphere composed of CO2 at <1 kPa. Ionic liquids are synthetic fluids with inherently low vapor pressure that are known to readily form boundary films under severe conditions. In an effort to improve the tribological performance of ILs, hydrocarbon-mimicking ionic liquids have recently been designed. This recent work has displayed significantly improved lubrication performance for steel – steel tribo-systems in air, compared to PFPEs or fluorine-based ILs. Also, as a consequence of the hydrocarbon-mimicking structure, compatibility with several conventional tribo-improving additives have been displayed. In this work, we evaluate these novel fluids in a reduced oxygen environment under boundary lubricated conditions to evaluate the effect of oxygen supply on boundary film formation.

     

  • 12.
    Nyberg, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Tomastik, Christian
    AC2T Research GmbH, Wiener-Neustadt, Austria.
    Dörr, Nicole
    AC2T Research GmbH, Wiener-Neustadt, Austria.
    Minami, Ichiro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Influence of atmosphere on boundary film formation from ionic liquids2018Conference paper (Refereed)
    Abstract [en]

    Modern space exploration missions, such as planetary exploration of Mars, have significantly different tribological concerns compared to conditions faced by mechanical devices in satellites. Space lubricants have traditionally implied extremely low vapor pressure, but limited performance in boundary lubrication. Mars devices on the other hand are subjected to heavier loads, while operating in an atmosphere composed of CO2 at <1 kPa. Ionic liquids are synthetic fluids with inherently low vapor pressure that are known to readily form boundary films under severe conditions. In our recent work, an ionic liquid designed as lubricant base fluid formed highly effective boundary films composed of silicate when evaluated in air. These boundary films include oxygen, which can possibly be supplied by the atmosphere or by the lubricant itself. In this work, we employ tribotesting in CO2, and N2, and perform surface analysis to evaluate the effect of oxygen supply on boundary film formation. 

1 - 12 of 12
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