Additives for Lubricants

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

Deadline for manuscript submissions: closed (20 November 2013) | Viewed by 155461

Special Issue Editors


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Guest Editor
Mechanical Engineering Department, University of New Hampshire, Kingsbury Hall, 33 Academic Way, Durham, NH 03824, USA
Interests: nitrides; carbides; sputter deposition; ion-assisted deposition; wear; friction; tool coatings
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Tribonex AB, Knivstagatan 12, 753 23 Uppsala, Sweden
Interests: lubricant formulations (engine oils, metalworking emulsions); solubility and lubricity issues; additives and surface chemistry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Neither mineral nor synthetic base oils can satisfy today’s lubricant performance requirements without using additives. Additives are chemical substances, in most part synthetic, which are used in lubricant formulations to adjust a broad of spectrum of properties by enhancing what is desired and suppressing what is unwanted. Many additives are multifunctional products that may exhibit synergistic or antagonistic behavior when mixed together. As a rule of thumb, additives do not add. This makes balancing and optimization of additive systems a challenging task.

The increasing focus on energy efficiency and environmental safety of lubricants poses new challenges for lubricant formulators, preventing or restricting the use of certain time-proven chemistries, such as ZDDP in engine oil or boric acid in MWF formulations. At the same time, it stimulates the search for new classes of additives, including all-organic ashless friction modifiers, nano-additives, and bio-based superlubricity additives, as well as fundamental studies into how individual additives work.

This special issue will examine current advances and future trends in lubricant additives. Contributions are solicited both from academic researchers working in the field of tribology and lubrication science and their industrial peers dealing with additive adpack development and lubricant formulation. The idea is to promote bi-directional information exchange whereby some practical challenges faced by lubricant industry are presented to university researchers and novel additive chemistries are exposed to industrial researchers and formulators involved in product development.

Prof. Dr. James E. Krzanowski
Dr. Boris Zhmud
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 submissions that pass pre-check are 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 2600 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

  • lubricant additives
  • friction modifiers
  • superlubricity
  • additive chemistry
  • synthetic oils

Published Papers (8 papers)

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Research

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625 KiB  
Communication
The Application of Molecular Dynamics in Fullerene-Based Journal Bearing Simulation
by Alexey Kornaev, Leonid Savin and Mikhail Nozdrichkin
Lubricants 2014, 2(1), 1-10; https://doi.org/10.3390/lubricants2010001 - 24 Feb 2014
Cited by 2 | Viewed by 6791
Abstract
The article is devoted to modeling of the molecular microscopic journal bearing. The walls and the lubricant of the bearing are fullerene-like molecules. On the basis of similarity theory and analysis of the dimensions, the similarity criterion is proposed. This criterion characterizes the [...] Read more.
The article is devoted to modeling of the molecular microscopic journal bearing. The walls and the lubricant of the bearing are fullerene-like molecules. On the basis of similarity theory and analysis of the dimensions, the similarity criterion is proposed. This criterion characterizes the convergence of a numerical solution. The test calculation is also made to evaluate the quality of the proposed criterion. Full article
(This article belongs to the Special Issue Additives for Lubricants)
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2173 KiB  
Article
On the Interactions of Additives in Metalworking Fluids with Metal Surfaces
by Joachim Schulz, Ekkard Brinksmeier and Daniel Meyer
Lubricants 2013, 1(4), 75-94; https://doi.org/10.3390/lubricants1040075 - 15 Nov 2013
Cited by 31 | Viewed by 12369
Abstract
Metalworking fluids (MWF) play a significant role in manufacturing processes, such as machining or forming. Consequently, a high number of MWF with varying chemical composition are commercially available. However, the working mechanisms of the MWF are still object of discussion in science and [...] Read more.
Metalworking fluids (MWF) play a significant role in manufacturing processes, such as machining or forming. Consequently, a high number of MWF with varying chemical composition are commercially available. However, the working mechanisms of the MWF are still object of discussion in science and application. This paper addresses the possible interactions of additives with metal surfaces taking the characteristic conditions in machining and forming processes as well as the chemical properties of the surface and the additives into account. The new model for possible interaction of additives with the metal surface is considered and supported by experimental data. This new model does not imply reaction layers as tribological active layer anymore. Full article
(This article belongs to the Special Issue Additives for Lubricants)
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4252 KiB  
Article
Interaction between Lubricants Containing Phosphate Ester Additives and Stainless Steels
by David W. Johnson, Matthew Bachus and John E. Hils
Lubricants 2013, 1(2), 48-60; https://doi.org/10.3390/lubricants1020048 - 17 May 2013
Cited by 19 | Viewed by 7938
Abstract
One way to improve fuel efficiency in today’s jet aircraft engines is to create an environment for higher operating temperatures and speeds. New and improved lubricants and bearing materials must be developed to remain stable in these elevated operating temperatures. Three lubricants, with [...] Read more.
One way to improve fuel efficiency in today’s jet aircraft engines is to create an environment for higher operating temperatures and speeds. New and improved lubricants and bearing materials must be developed to remain stable in these elevated operating temperatures. Three lubricants, with varying amounts of tricresyl phosphate added as an anti-wear/extreme pressure additive were tested on two different stainless steels at varying temperatures ranging from 300 °C to 350 °C in vacuum. Significant decomposition of the lubricant base-stocks and the phosphate ester additive did occur in most of the trials resulting in the formation of carboxylic acids and phenols. In these cases a film containing phosphorus was deposited onto the stainless steel substrate. Full article
(This article belongs to the Special Issue Additives for Lubricants)
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Review

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1457 KiB  
Review
Graphite and Hybrid Nanomaterials as Lubricant Additives
by Zhenyu J. Zhang, Dorin Simionesie and Carl Schaschke
Lubricants 2014, 2(2), 44-65; https://doi.org/10.3390/lubricants2020044 - 24 Apr 2014
Cited by 102 | Viewed by 15965
Abstract
Lubricant additives, based on inorganic nanoparticles coated with organic outer layer, can reduce wear and increase load-carrying capacity of base oil remarkably, indicating the great potential of hybrid nanoparticles as anti-wear and extreme-pressure additives with excellent levels of performance. The organic part in [...] Read more.
Lubricant additives, based on inorganic nanoparticles coated with organic outer layer, can reduce wear and increase load-carrying capacity of base oil remarkably, indicating the great potential of hybrid nanoparticles as anti-wear and extreme-pressure additives with excellent levels of performance. The organic part in the hybrid materials improves their flexibility and stability, while the inorganic part is responsible for hardness. The relationship between the design parameters of the organic coatings, such as molecular architecture and the lubrication performance, however, remains to be fully elucidated. A survey of current understanding of hybrid nanoparticles as lubricant additives is presented in this review. Full article
(This article belongs to the Special Issue Additives for Lubricants)
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264 KiB  
Review
Lubricants in Pharmaceutical Solid Dosage Forms
by Jinjiang Li and Yongmei Wu
Lubricants 2014, 2(1), 21-43; https://doi.org/10.3390/lubricants2010021 - 25 Feb 2014
Cited by 167 | Viewed by 58175
Abstract
Lubrication plays a key role in successful manufacturing of pharmaceutical solid dosage forms; lubricants are essential ingredients in robust formulations to achieve this. Although many failures in pharmaceutical manufacturing operations are caused by issues related to lubrication, in general, lubricants do not gain [...] Read more.
Lubrication plays a key role in successful manufacturing of pharmaceutical solid dosage forms; lubricants are essential ingredients in robust formulations to achieve this. Although many failures in pharmaceutical manufacturing operations are caused by issues related to lubrication, in general, lubricants do not gain adequate attention in the development of pharmaceutical formulations. In this paper, the fundamental background on lubrication is introduced, in which the relationships between lubrication and friction/adhesion forces are discussed. Then, the application of lubrication in the development of pharmaceutical products and manufacturing processes is discussed with an emphasis on magnesium stearate. In particular, the effect of its hydration state (anhydrate, monohydrate, dihydrate, and trihydrate) and its powder characteristics on lubrication efficiency, as well as product and process performance is summarized. In addition, the impact of lubrication on the dynamics of compaction/compression processes and on the mechanical properties of compacts/tablets is presented. Furthermore, the online monitoring of magnesium stearate in a blending process is briefly mentioned. Finally, the chemical compatibility of active pharmaceutical ingredient (API) with magnesium stearate and its reactive impurities is reviewed with examples from the literature illustrating the various reaction mechanisms involved. Full article
(This article belongs to the Special Issue Additives for Lubricants)
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1931 KiB  
Review
Lubricants for Metal Belt Continuously Variable Transmissions
by Keiichi Narita
Lubricants 2014, 2(1), 11-20; https://doi.org/10.3390/lubricants2010011 - 25 Feb 2014
Cited by 6 | Viewed by 8293
Abstract
This paper reviews the effects of lubricant additives and base stock used in metal belt continuously variable transmissions (CVT) fluids on the CVT transmission torque capacity. Additive formulation composed of phosphorus anti-wear agent, calcium detergent, and dispersant improved the friction coefficient between the [...] Read more.
This paper reviews the effects of lubricant additives and base stock used in metal belt continuously variable transmissions (CVT) fluids on the CVT transmission torque capacity. Additive formulation composed of phosphorus anti-wear agent, calcium detergent, and dispersant improved the friction coefficient between the metals. The analysis on the post-test surface suggests that the friction behavior strongly depends on the local morphology of the tribofilms derived from lubricant additives. Examining the effect of base stock on the torque capacity in actual belt CVTs revealed that SN (synthetic naphthene) exhibited 10% higher torque capacity than that of PAO (polyalphaolefin). It is believed that the difference in the torque capacity is due to the difference in the oil-film shearing force generated by the relative sliding between the belt and pulley. Full article
(This article belongs to the Special Issue Additives for Lubricants)
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538 KiB  
Review
Phosphate Esters, Thiophosphate Esters and Metal Thiophosphates as Lubricant Additives
by David W. Johnson and John E. Hils
Lubricants 2013, 1(4), 132-148; https://doi.org/10.3390/lubricants1040132 - 18 Dec 2013
Cited by 82 | Viewed by 35485
Abstract
Phosphate esters, thiophosphate esters and metal thiophosphates have been used as lubricant additives for over 50 years. While their use has been extensive, a detailed knowledge of how they work has been a much more recent development. In this paper, the use of [...] Read more.
Phosphate esters, thiophosphate esters and metal thiophosphates have been used as lubricant additives for over 50 years. While their use has been extensive, a detailed knowledge of how they work has been a much more recent development. In this paper, the use of phosphate esters and thiophosphate esters as anti-wear or extreme pressure additives is reviewed with an emphasis on their mechanism of action. The review includes the use of alkyl phosphates, triaryl phosphates and metal containing thiophosphate esters. The mechanisms of these materials interacting with a range of iron and steel based bearing material are examined. Full article
(This article belongs to the Special Issue Additives for Lubricants)
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Other

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706 KiB  
Technical Note
Nanomaterials in Lubricants: An Industrial Perspective on Current Research
by Boris Zhmud and Bogdan Pasalskiy
Lubricants 2013, 1(4), 95-101; https://doi.org/10.3390/lubricants1040095 - 20 Nov 2013
Cited by 56 | Viewed by 8847
Abstract
This paper presents an overview on the use of various classes of nanomaterials in lubricant formulations. The following classes of nanomaterials are considered: fullerenes, nanodiamonds, ultradispersed boric acid and polytetrafluoroethylene (PTFE). Current advances in using nanomaterials in engine oils, industrial lubricants and greases [...] Read more.
This paper presents an overview on the use of various classes of nanomaterials in lubricant formulations. The following classes of nanomaterials are considered: fullerenes, nanodiamonds, ultradispersed boric acid and polytetrafluoroethylene (PTFE). Current advances in using nanomaterials in engine oils, industrial lubricants and greases are discussed. Results of numerous studies combined with formulation experience of the authors strongly suggest that nanomaterials do indeed have potential for enhancing certain lubricant properties, yet there is a long way to go before balanced formulations are developed. Full article
(This article belongs to the Special Issue Additives for Lubricants)
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