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Publications (10 of 11) Show all publications
Nyberg, E., Tomastik, C., Dörr, N. & Minami, I. (2018). Boundary Film Formation of P-SiSO in Reduced Oxygen Atmosphere. In: NORDTRIB 2018: . Paper presented at 18th Nordic Symposium on Tribology – NORDTRIB 2018, Uppsala, 18-21 June 2018. Uppsala
Open this publication in new window or tab >>Boundary Film Formation of P-SiSO in Reduced Oxygen Atmosphere
2018 (English)In: NORDTRIB 2018, Uppsala, 2018Conference paper, Oral presentation with published abstract (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.

 

Place, publisher, year, edition, pages
Uppsala: , 2018
Keywords
Tribology, boundary film
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-70345 (URN)
Conference
18th Nordic Symposium on Tribology – NORDTRIB 2018, Uppsala, 18-21 June 2018
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-14Bibliographically approved
Nyberg, E., Tomastik, C., Dörr, N. & Minami, I. (2018). Influence of atmosphere on boundary film formation from ionic liquids. In: : . Paper presented at 73rd STLE Annual Meeting & Exhibition, Minneapolis, Minnesota, May 20-24 2018. Minneapolis, MN
Open this publication in new window or tab >>Influence of atmosphere on boundary film formation from ionic liquids
2018 (English)Conference paper, Oral presentation with published abstract (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. 

Place, publisher, year, edition, pages
Minneapolis, MN: , 2018
Keywords
Tribology, ionic liquids, boundary film, atmosphere
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-70343 (URN)
Conference
73rd STLE Annual Meeting & Exhibition, Minneapolis, Minnesota, May 20-24 2018
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-14Bibliographically approved
Nyberg, E., Grahn, M. & Minami, I. (2017). Additives to Improve Tribological Properties of Ionic Liquid as Base Fluids. In: : . Paper presented at 72nd STLE Annual Meeting & Exhibition, Atlanta, GA, May 21-25 2017. Atlanta, GA
Open this publication in new window or tab >>Additives to Improve Tribological Properties of Ionic Liquid as Base Fluids
2017 (English)Conference paper, Oral presentation with published abstract (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.

Place, publisher, year, edition, pages
Atlanta, GA: , 2017
Keywords
Tribology, ionic liquids, friction, wear, performance additive
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear) Chemical Process Engineering
Research subject
Machine Elements; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-70341 (URN)
Conference
72nd STLE Annual Meeting & Exhibition, Atlanta, GA, May 21-25 2017
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-14Bibliographically approved
Nyberg, E. & Minami, I. (2017). Boundary Film Formation from Hydrocarbon-mimicking Ionic Liquids. In: : . Paper presented at ÖTG Symposium 2017, Tribologie in Industrie und Forschung, Neue Aufgaben – innovative Lösungen, Wiener Neustadt, Austria, 22/11 2017. Wiener Neustadt, Austria
Open this publication in new window or tab >>Boundary Film Formation from Hydrocarbon-mimicking Ionic Liquids
2017 (English)Conference paper, Published 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.

Place, publisher, year, edition, pages
Wiener Neustadt, Austria: , 2017
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-70342 (URN)
Conference
ÖTG Symposium 2017, Tribologie in Industrie und Forschung, Neue Aufgaben – innovative Lösungen, Wiener Neustadt, Austria, 22/11 2017
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-14Bibliographically approved
Hansen, J., Björling, M., Nyberg, E. & Larsson, R. (2017). Elastohydrodynamic performance of a hydrocarbon mimicking ionic liquid additive. In: : . Paper presented at STLE Annual Meeting & Exhibition, Atlanta, USA, May 22-25.
Open this publication in new window or tab >>Elastohydrodynamic performance of a hydrocarbon mimicking ionic liquid additive
2017 (English)Conference paper, Oral presentation with published abstract (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

National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-66451 (URN)
Conference
STLE Annual Meeting & Exhibition, Atlanta, USA, May 22-25
Available from: 2017-11-07 Created: 2017-11-07 Last updated: 2018-01-13Bibliographically approved
Nyberg, E., Mouzon, J., Grahn, M. & Minami, I. (2017). Formation of Boundary Film from Ionic Liquids Enhanced by Additives. Applied Sciences, 7(5), Article ID 433.
Open this publication in new window or tab >>Formation of Boundary Film from Ionic Liquids Enhanced by Additives
2017 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 7, no 5, article id 433Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Basel: MDPI, 2017
Keywords
gränsskiktssmörjning, jonvätska, friktion, nötning, tribologi
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear) Chemical Process Engineering
Research subject
Machine Elements; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-63211 (URN)10.3390/app7050433 (DOI)000404449000002 ()2-s2.0-85018920929 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-05-10 (rokbeg)

Available from: 2017-05-02 Created: 2017-05-02 Last updated: 2018-11-26Bibliographically approved
Nyberg, E. (2017). Ionic liquids as lubricants for mechanical devices on Mars. In: : . Paper presented at Rymdforum 2017, Kiruna, 8-10 maj 2017. Kiruna
Open this publication in new window or tab >>Ionic liquids as lubricants for mechanical devices on Mars
2017 (English)Conference paper, Poster (with or without abstract) (Other academic)
Place, publisher, year, edition, pages
Kiruna: , 2017
National Category
Aerospace Engineering Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-70339 (URN)
Conference
Rymdforum 2017, Kiruna, 8-10 maj 2017
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-14Bibliographically approved
Nyberg, E. (2017). Lubrication mechanism of hydrocarbon-mimicking ionic liquids. (Licentiate dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Lubrication mechanism of hydrocarbon-mimicking ionic liquids
2017 (English)Licentiate 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.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2017
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Keywords
P-SiSO, boundary film, silicate, friction, wear, anti-wear, friction modifier, base fluid
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-65505 (URN)978-91-7583-953-0 (ISBN)978-91-7583-954-7 (ISBN)
Presentation
2017-11-02, E231, Luleå, 09:00 (English)
Supervisors
Projects
Projekt: Rymdforskarskolan 2015
Available from: 2017-09-06 Created: 2017-09-05 Last updated: 2018-01-13Bibliographically approved
Nyberg, E., Respatiningsih, C. & Minami, I. (2017). Molecular design of advanced lubricant base fluids: hydrocarbon-mimicking ionic liquids. RSC Advances, 7(11), 6364-6373
Open this publication in new window or tab >>Molecular design of advanced lubricant base fluids: hydrocarbon-mimicking ionic liquids
2017 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 11, p. 6364-6373Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
RSC Publishing, 2017
Keywords
additive compatibility, synthetic lubricant, friction modification, wear prevention, tetraalkylphosphonium, RTIL
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-61571 (URN)10.1039/C6RA27065D (DOI)000393755100024 ()2-s2.0-85010341504 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-02-07 (andbra)

Available from: 2017-01-21 Created: 2017-01-21 Last updated: 2018-12-14Bibliographically approved
Nyberg, E., Dörr, N., Igartua, A. & Minami, I. (2016). Improvement in the Tribological Performance of Room Temperature Ionic Liquids by Additive Technology. In: Nordic Symposium on Tribology - NORDTRIB 2016: . Paper presented at 17th Nordic Symposium on Tribology - NORDTRIB 2016, Aulanko, Hämeenlinna, Finland, 14–17 June 2016. Hämeenlinna, Finland
Open this publication in new window or tab >>Improvement in the Tribological Performance of Room Temperature Ionic Liquids by Additive Technology
2016 (English)In: Nordic Symposium on Tribology - NORDTRIB 2016, Hämeenlinna, Finland, 2016Conference paper, Oral presentation with published abstract (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.

Place, publisher, year, edition, pages
Hämeenlinna, Finland: , 2016
Keywords
Tribology, friction, wear, ionic liquids, additive
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-70338 (URN)
Conference
17th Nordic Symposium on Tribology - NORDTRIB 2016, Aulanko, Hämeenlinna, Finland, 14–17 June 2016
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-14Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-0851-8475

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