Special Issue "Nanoparticles and Ionic Liquids in Lubrication"

A special issue of Lubricants (ISSN 2075-4442).

Deadline for manuscript submissions: closed (31 March 2016).

Special Issue Editors

Guest Editor
Prof. Dr. Antolin Hernández Battez

Department of Construction and Manufacturing Engineering, University of Oviedo, Campus de Gijon, Asturias, Spain
Website | E-Mail
Fax: +34-985182433
Interests: friction; wear; nanoparticles; ionic liquids; additives; experimental techniques in tribology
Guest Editor
Dr. Rubén González

Department of Marine Science and Technology, University of Oviedo, 33203 Gijon, Asturias, Spain
Website | E-Mail
Phone: +34985182419
Fax: +34-985182433
Interests: thermal spray; laser cladding; DLC and PVD coatings; green tribology; energy efficiency; biodegradability and bacterial toxicity of lubricants; tribological properties of ionic liquids as lubricant additives and as neat lubricants; nanoparticles as lubricant additives; wear mechanisms; real-time lubricant condition monitoring

Special Issue Information

Dear Colleagues,

The great influence of friction, lubrication, and wear on the efficiency and lifetime of machinery has been recognized since the mid-1960s. Multiple strategies can be adopted for energy and material conservation through tribology. From the lubrication point of view, the development of novel and better base oils and additives is one of the approaches chosen in the field of lubricant oils and greases. Also, the use of coatings as solid lubricants and the development of new materials have been also addressed.

Since 2001, the idea of using ionic liquids in lubrication, as neat lubricants and as additives, is a growing research line. On the other hand, the use of nanoparticles as lubricant additives and as fillers in nanocomposites for improving anti-friction and anti-wear properties, continues to be a hot research topic.

This Special Issue will show current advances and future trends about the use of nanoparticles and ionic liquids in the lubrication field. Contributions are welcome, from both academic researchers working in the field of tribology and lubrication science and from their industrial peers dealing with lubricant formulation, coating design, and nanocomposite manufacturing. We would like to promote an exciting information exchange whereby academic researchers present new ideas to industrial researchers and the current challenges faced by the industrial researchers are presented to their partners in the academy.

Prof. Dr. Antolin Hernández Battez
Prof. Dr. Rubén González Rodríguez
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Lubricants is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


Keywords

  • nanoparticles
  • ionic liquids
  • lubricant additives
  • nanofluids
  • solid lubricants
  • friction modifiers
  • nanocomposites
  • coatings

Published Papers (10 papers)

View options order results:
result details:
Displaying articles 1-10
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle
Multi-Phase Friction and Wear Reduction by Copper Nanopartices
Received: 19 August 2016 / Revised: 20 September 2016 / Accepted: 21 September 2016 / Published: 18 October 2016
Cited by 9 | PDF Full-text (5583 KB) | HTML Full-text | XML Full-text
Abstract
Finely dispersed copper nanoparticles were added as an additive to fully-formulated engine oils. The copper additive was in colloidal form, with an inner core of Cu2+ atoms covered by surfactants to form stable reverse micelles that are completely dispersible in the base [...] Read more.
Finely dispersed copper nanoparticles were added as an additive to fully-formulated engine oils. The copper additive was in colloidal form, with an inner core of Cu2+ atoms covered by surfactants to form stable reverse micelles that are completely dispersible in the base oil. The tribological process to form protective films at the metal surface is comprised of three phases. Phase I can be considered a physical process involving the build-up of polar molecules by absorption to produce a friction modifier film, whereas phases II and III have to be treated as mechanochemical processes comprising a combination of redox reactions and a third body formation. The tribological performance was investigated using atomic force microscopy, a microtribometer, a pin-on-disk tribometer in combination with continuous and high-resolution wear measurements with radionuclide technique, and high pressure stressing in a thrust roller bearing test rig. In addition, the nanostructure of the additive was characterized by atomic force microscopy. Finally, the chemical composition of the metal surface was analyzed using photoelectron spectroscopy. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Open AccessArticle
Formation of Anti-Wear Tribofilms via α-ZrP Nanoplatelet as Lubricant Additives
Received: 26 April 2016 / Revised: 7 July 2016 / Accepted: 29 July 2016 / Published: 5 August 2016
Cited by 13 | PDF Full-text (4939 KB) | HTML Full-text | XML Full-text
Abstract
Effective tribofilms are desirable to protect mechanical systems. In the present research, we investigated the formation of a tribofilm through the use of α-ZrP (Zr(HPO4)2·H2O) as an additive. Experiments were conducted on a base oil where 0.2 [...] Read more.
Effective tribofilms are desirable to protect mechanical systems. In the present research, we investigated the formation of a tribofilm through the use of α-ZrP (Zr(HPO4)2·H2O) as an additive. Experiments were conducted on a base oil where 0.2 wt% of the additive was used. Experimental results showed a 50% reduction in friction and a 30% reduction in wear when compared to the base oil containing 0.8 wt% ZDDP. Spectroscopic characterization indicated that the tribofilm consists of iron oxide, zirconium oxide, and zirconium phosphates. The worn surface was seen to be smooth which renders it desirable for bearing systems. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Open AccessArticle
Towards Phosphorus Free Ionic Liquid Anti-Wear Lubricant Additives
Received: 15 April 2016 / Revised: 15 June 2016 / Accepted: 16 June 2016 / Published: 22 June 2016
Cited by 11 | PDF Full-text (4222 KB) | HTML Full-text | XML Full-text
Abstract
The development of improved anti-wear additives would enable the use of lower viscosity oils that would lead to improved efficiency. Ionic liquids have the potential to be this type of new anti-wear additive. However, currently the best performing ionic liquids that are miscible [...] Read more.
The development of improved anti-wear additives would enable the use of lower viscosity oils that would lead to improved efficiency. Ionic liquids have the potential to be this type of new anti-wear additive. However, currently the best performing ionic liquids that are miscible in non-polar base oils, the phosphonium phosphates, contain phosphorus on both the cation and anion. Manufacturers are seeking to reduce the presence of phosphorus in oils. Here, as a first step towards phosphorus-free anti-wear additives, we have investigated ionic liquids similar to the phosphonium phosphates but having either a phosphorus-free cation or anion. Two quaternary ammonium phosphates (N6,6,6,14)(BEHP) and (N8,8,8,8)(BEHP) and a phosphonium silyl-sulfonate (P6,6,6,14)(SSi) were compared to a phosphonium phosphate (P6,6,6,14)(BEHP) and a traditional zinc dithiophosphate (ZDDP) as anti-wear additives in mineral oil. The change from a phosphonium to a quaternary ammonium cation drastically reduced the miscibility of the Ionic liquid (IL) in the oil, while the change to a smaller silicon containing anion also resulted in limited miscibility. For the pin-on-disk wear test conditions used here none of the ionic liquids outperformed the ZDDP except the (P6,6,6,14)(BEHP) at a relatively high loading of 0.10 mol·kg−1 (approximately 8 wt%). At a more moderate loading of 0.025 mol·kg−1 the (P6,6,6,14)(SSi) was the best performing ionic liquid by a significant amount, reducing the wear to 44% of the neat mineral oil, while the ZDDP reduced the wear to 25% of the mineral oil value. Electron microscopy and energy dispersive X-ray spectroscopy showed that the presence of a silicon containing tribofilm was responsible for this protective behaviour, suggesting that silicon containing ionic liquids should be further investigated as anti-wear additives for oils. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Open AccessArticle
Theoretical and Experimental Study of the Friction Behavior of Halogen-Free Ionic Liquids in Elastohydrodynamic Regime
Received: 31 March 2016 / Revised: 8 May 2016 / Accepted: 11 May 2016 / Published: 19 May 2016
Cited by 4 | PDF Full-text (2310 KB) | HTML Full-text | XML Full-text
Abstract
Ionic Liquids have emerged as effective lubricants and additives to lubricants, in the last decade. Halogen-free ionic liquids have recently been considered as more environmentally stable than their halogenated counterparts, which tend to form highly toxic and corrosive acids when exposed to moisture. [...] Read more.
Ionic Liquids have emerged as effective lubricants and additives to lubricants, in the last decade. Halogen-free ionic liquids have recently been considered as more environmentally stable than their halogenated counterparts, which tend to form highly toxic and corrosive acids when exposed to moisture. Most of the studies using ionic liquids as lubricants or additives of lubricants have been done experimentally. Due to the complex nature of the lubrication mechanism of these ordered fluids, the development of a theoretical model that predicts the ionic liquid lubrication ability is currently one of the biggest challenges in tribology. In this study, a suitable and existing friction model to describe lubricating ability of ionic liquids in the elastohydrodynamic lubrication regime is identified and compared to experimental results. Two phosphonium-based, halogen-free ionic liquids are studied as additives to a Polyalphaolefin base oil in steel–steel contacts using a ball-on-flat reciprocating tribometer. Experimental conditions (speed, load and roughness) are selected to ensure that operations are carried out in the elastohydrodynamic regime. Wear volume was also calculated for tests at high speed. A good agreement was found between the model and the experimental results when [THTDP][Phos] was used as an additive to the base oil, but some divergence was noticed when [THTDP][DCN] was added, particularly at the highest speed studied. A significant decrease in the steel disks wear volume is observed when 2.5 wt. % of the two ionic liquids were added to the base lubricant. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Open AccessArticle
The Lubrication Ability of Ionic Liquids as Additives for Wind Turbine Gearboxes Oils
Received: 22 March 2016 / Revised: 11 April 2016 / Accepted: 22 April 2016 / Published: 5 May 2016
Cited by 8 | PDF Full-text (3897 KB) | HTML Full-text | XML Full-text
Abstract
The amount of energy that can be gained from the wind is unlimited, unlike current energy sources such as fossil and coal. While there is an important push in the use of wind energy, gears and bearing components of the turbines often fail [...] Read more.
The amount of energy that can be gained from the wind is unlimited, unlike current energy sources such as fossil and coal. While there is an important push in the use of wind energy, gears and bearing components of the turbines often fail due to contact fatigue, causing costly repairs and downtime. The objective of this work is to investigate the potential tribological benefits of two phosphonium-based ionic liquids (ILs) as additives to a synthetic lubricant without additives and to a fully formulated and commercially available wind turbine oil. In this work, AISI 52100 steel disks were tested in a ball-on-flat reciprocating tribometer against AISI 440C steel balls. Surface finish also affects the tribological properties of gear surfaces. In order to understand the combined effect of using the ILs with surface finish, two surface finishes were also used in this study. Adding ILs to the commercial available or synthetic lubricant reduced the wear scar diameter for both surface finishes. This decrease was particularly important for trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl) amide, where a wear reduction of the steel disk around 20% and 23% is reached when 5 wt % of this IL is added to the commercially available lubricant and to the synthetic lubricant without additives, respectively. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Open AccessArticle
The Study of Mechanical and Tribological Performance of Fulleroid Materials Filled PA 6 Composites
Received: 27 November 2015 / Revised: 12 April 2016 / Accepted: 14 April 2016 / Published: 28 April 2016
Cited by 1 | PDF Full-text (2106 KB) | HTML Full-text | XML Full-text
Abstract
The effect of fulleroid materials (fullerene С60 and fullerene soot which is used for fullerene production) and carbon fibers on the mechanical and tribological properties of polymer nanocomposites based on polyamide 6 (PA6) was investigated. Composites were synthesized by in situ polymerization [...] Read more.
The effect of fulleroid materials (fullerene С60 and fullerene soot which is used for fullerene production) and carbon fibers on the mechanical and tribological properties of polymer nanocomposites based on polyamide 6 (PA6) was investigated. Composites were synthesized by in situ polymerization and direct mixing in an extruder. It was found that addition of these fillers during in situ polymerization was more effective at improving the mechanical and tribological properties of the composites. The use of the nanoparticles was an effective way to decrease the friction coefficient of the polymer composites because the fillers were the same size as the segments of the surrounding polymer chains. The steady state coefficients of friction with the addition of fulleroid fillers were lower than that of unfilled PA6. The lowest coefficient of friction was observed for PA6 filled with 1 wt. % fullerene soot. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Open AccessArticle
Tribological Properties of the Lubricant Containing Titanium Dioxide Nanoparticles as an Additive
Received: 4 January 2016 / Revised: 12 April 2016 / Accepted: 12 April 2016 / Published: 21 April 2016
Cited by 17 | PDF Full-text (1525 KB) | HTML Full-text | XML Full-text
Abstract
To improve the oil-solubility of nanoparticles, a new technology was used to prepare a kind of lubricant containing titanium dioxide (TiO2) nanoparticles. The microstructures of the prepared nanoparticles were characterized via transmission electron microscope (TEM) and infrared spectroscopy (IR). Tribological properties [...] Read more.
To improve the oil-solubility of nanoparticles, a new technology was used to prepare a kind of lubricant containing titanium dioxide (TiO2) nanoparticles. The microstructures of the prepared nanoparticles were characterized via transmission electron microscope (TEM) and infrared spectroscopy (IR). Tribological properties of TiO2 nanoparticles used as an additive in base oil were evaluated using four-ball tribometer and ball-on-disk tribometer. In addition, the worn surface of the steel ball was investigated via polarized microscopy (PM) and X-ray photoelectron spectroscopy (XPS). The TiO2 nanoparticles can be completely well-dispersed in the base oil under a new process (NP), which has no significantly negative effect on the anti-oxidation property. The results of the tribological tests show that TiO2 nanoparticles under the NP show a better anti-wear property and friction-reducing property in base oil compared to TiO2 nanoparticles under the tradition process (TP). The main aim of this paper lies in solving with the oil-solubility problem through the combination effect of surface modification and special blend process of lubricating oil. This method was first used to prepare lubricant containing TiO2 nanoparticles and then used as additives in engine oil, gear oil, and other industrial lubricants. At the same time, tribological properties of TiO2 nanoparticles in base oil as a lubricating additive were also studied. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Open AccessArticle
Tribological Behaviour of PVD Coatings Lubricated with a FAP Anion-Based Ionic Liquid Used as an Additive
Received: 9 February 2016 / Revised: 9 March 2016 / Accepted: 11 March 2016 / Published: 17 March 2016
Cited by 6 | PDF Full-text (4365 KB) | HTML Full-text | XML Full-text
Abstract
This paper studies 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate ionic liquid ([BMP][FAP]) as a 1 wt% additive to a polyalphaolefin (PAO 6) in the lubrication of CrN and TiN PVD coatings. Friction and wear behaviour were determined by using a ball-on-plate reciprocating tribometer at two loads [...] Read more.
This paper studies 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate ionic liquid ([BMP][FAP]) as a 1 wt% additive to a polyalphaolefin (PAO 6) in the lubrication of CrN and TiN PVD coatings. Friction and wear behaviour were determined by using a ball-on-plate reciprocating tribometer at two loads (20 and 40 N) and a reciprocating frequency of 10 Hz. The tribological behaviour of this mixture has also been compared to a traditional oil additive, like zinc dialkyldithiophosphate (ZDDP). As an additive, ionic liquid exhibited an important friction and wear reduction compared to the base oil. However, tests conducted with ZDDP show slightly better results. XPS was used to analyse wear surfaces. The interactions of each additive with the surface contributed to improving the tribological behaviour of the lubricants. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Open AccessArticle
Ionic Liquids as Additives of Coffee Bean Oil in Steel-Steel Contacts
Lubricants 2015, 3(4), 637-649; https://doi.org/10.3390/lubricants3040637
Received: 2 September 2015 / Revised: 19 October 2015 / Accepted: 21 October 2015 / Published: 28 October 2015
Cited by 8 | PDF Full-text (1501 KB) | HTML Full-text | XML Full-text
Abstract
Environmental awareness and ever-growing restrictive regulations over contamination have increased the need for more environmentally-friendly lubricants. Due to their superior biodegradability and lower toxicity, vegetable oils are a good alternative to replace currently-used mineral oils. However, vegetable oils show low oxidation and thermal [...] Read more.
Environmental awareness and ever-growing restrictive regulations over contamination have increased the need for more environmentally-friendly lubricants. Due to their superior biodegradability and lower toxicity, vegetable oils are a good alternative to replace currently-used mineral oils. However, vegetable oils show low oxidation and thermal stability and poor anti-wear properties. Most of these drawbacks can be attenuated through the use of additives. In the last decade, ionic liquids have emerged as high-performance fluids and lubricant additives due to their unique characteristics. In this study, the tribological behavior of two phosphonium-based ionic liquids is investigated as additives of coffee bean oil in steel-steel contact. Coffee bean oil-ionic liquid blends containing 1, 2.5, and 5 wt% of each ionic liquid are studied using a block-on-flat reciprocating tribometer and the test results are compared to commercially-available, fully-formulated lubricant. Results showed that the addition of the ionic liquids to the coffee bean oil reduces wear volume of the steel disks, and wear values achieved are comparable to that obtained when the commercially-available lubricant is used. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Review

Jump to: Research

Open AccessReview
Ionic Nanofluids in Tribology
Lubricants 2015, 3(4), 650-663; https://doi.org/10.3390/lubricants3040650
Received: 15 September 2015 / Revised: 22 October 2015 / Accepted: 22 October 2015 / Published: 27 November 2015
Cited by 14 | PDF Full-text (638 KB) | HTML Full-text | XML Full-text
Abstract
This overview covers the most recent developments in the field of ionic nanofluid lubricants, defined as dispersions of nanoparticles with ionic liquids through the activation of nanophases. The nanophases range from metal nanoparticles and ceramic inorganic nanoparticles, to different carbon nanophases. The combinations [...] Read more.
This overview covers the most recent developments in the field of ionic nanofluid lubricants, defined as dispersions of nanoparticles with ionic liquids through the activation of nanophases. The nanophases range from metal nanoparticles and ceramic inorganic nanoparticles, to different carbon nanophases. The combinations with room-temperature ionic liquids can be in the form of mixtures, dispersions, surface-modified nanophases, or chemically-functionalized nanophases. The new ionic nanofluids can be used as base lubricants, as lubricant additives, or as anti-friction and wear-reducing additives in new nanocomposite materials. Full article
(This article belongs to the Special Issue Nanoparticles and Ionic Liquids in Lubrication)
Figures

Figure 1

Lubricants EISSN 2075-4442 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top