The influence of contact conditions on surface reaction layers formed between steel surfaces lubricated by an aviation oil

Wang, L.; Wood, R.J.K.

doi:10.1016/j.triboint.2007.02.014

Cited by 12 publications

(10 citation statements)

References 23 publications

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“…The thermal reaction films formed on the Fe (with and without nanodiamonds) and baked Fe (with nanodiamonds) revealed the presence of phosphorus, whereas the surfaces with no reaction films had no phosphorus content. The TCP thermal reaction films have been reported in prior literature [3,19,26] to comprise inorganic phosphates, consistent with the increase in P and O content but not the significant increase in C content. With the presence of nanodiamonds, the thermal reaction films on both the Fe and baked Fe surfaces had significantly higher levels of C compared to films without nanodiamonds.…”

Section: Eds Measurements Of Film Chemical Compositionssupporting

confidence: 88%

Synergistic Effect of Nanodiamond and Phosphate Ester Anti-Wear Additive Blends

et al. 2018

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Nanodiamonds are known to improve tribological performance when added to lubricants, but their impact on additives that may already be present in the lubricant is poorly documented. Here, we report on a study of their effects on thermal reaction films formed from tricresyl phosphate (TCP) on Fe substrates immersed in a dibasic ester basestock when blended with TCP. Thermal reaction film formation temperatures were recorded in-situ by monitoring the reaction film formation on both Fe and air baked Fe surfaces using a quartz crystal microbalance (QCM). The nanodiamonds were found to raise the thermal reaction film formation temperature by 18 • C, possibly by raising the activation energy for the reaction, but they were not observed to affect the thickness or rate of formation of the films. The nanodiamonds, moreover, were observed to trigger thermal reaction film formation on air baked Fe surfaces that otherwise were highly resistance to reaction film formation. The surface morphology, roughness, and thickness of the thermal reaction films, as measured by atomic force microscopy (AFM), are reported as well as their chemical compositions, as studied with Electron Dispersive X-ray Spectroscopy (EDS). The coefficients of friction measured on the thermal reaction films during dry solid-solid contact are also reported.Lubricants 2018, 6, 56 2 of 14 existing phosphate esters additives, rather than outright replacing them. An appropriate strategy to limit their use levels while also retaining their function is to blend them with a synergistic and environmentally friendly additive. The overarching goal here is to add the synergistic additive without increasing the amount of phosphorus in the system until it is required to do so. This strategy would be completely practical to implement and applicable in various fields, such as aviation, automobiles, manufacturing, defense, etc., that implement a condition-based maintenance schedule [8].Nanomaterials are emerging as environmentally friendly and effective additives for controlling friction and wear in various applications [9]. Several physical mechanisms such as change in friction mode (sliding to rolling), surface polishing/mending, reduction in cohesive forces via layered materials, etc., and chemical mechanisms, including material delivery/transfer for catalysis, tribofilm formation by tribochemical reactions, etc., have been identified as lubrication mechanisms for nanomaterials [10]. However, nanomaterials should also be able to withstand tough environments under EP conditions during boundary lubrication and the high operating temperatures of aircraft engines if they are to be successfully blended with currently used additives. This requires that nanomaterials have, among other properties, a high melting point, high hardness, and favorable chemical reactions to allow rigid bonding onto the surface, together with the anti-wear film produced by the phosphate ester [5].Among the nanomaterials discovered and studied so far, nanodiamonds are the leading candidates from the po...

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Section: Eds Measurements Of Film Chemical Compositionssupporting

confidence: 88%

Synergistic Effect of Nanodiamond and Phosphate Ester Anti-Wear Additive Blends

et al. 2018

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“…As one of the most used additives of lubricating oil [16][17][18][19][20][21][22][23][24], phosphate can be used to make an ionic liquid possessing both excellent lubrication/anti-wear characteristics and no corrosion issue to metallic friction pairs if phosphate could be modified by being coordinated with some cations that cannot be easily hydrolyzed. Inspired by this idea, a series of ionic liquids consisting of phosphate anions and alkylimidazolium cation were synthesized, and the tribological properties of these ionic liquids as lubricants were studied as well.…”

Section: Introductionmentioning

confidence: 99%

Tribological Characteristics of Alkylimidazolium Diethyl Phosphates Ionic Liquids as Lubricants for Steel–Steel Contact

Zhang

Duan

2009

Tribol Lett

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Tribological properties of three novel phosphates-based ionic liquids (ILs), i.e., 1,3-diethyl imidazolium diethylphosphate, 1-ethyl-3-butyl imidazolium diethylphosphate, and 1-ethyl-3-octyl imidazolium diethylphosphate, were evaluated as lubricants for the steelsteel sliding pair by using an Optimol-SRV oscillating friction and wear tester. The chemical compositions of the boundary films generated on steel contact surfaces were analyzed with the use of a scanning electron microscope (SEM) with a Kevex energy dispersive X-ray analyzer attachment (EDS), and an X-ray photoelectron spectrometer (XPS). The results showed that these phosphate functional group-containing ionic liquids exhibit excellent tribological performance especially at a moderate temperature. The imidazole phosphate ionic liquid has no corrosion to steel. The mechanism for the friction-reduction and anti-wear effect of ionic liquids has also been proposed and discussed from the tribochemistry point of view.

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“…In traditional tribology systems, tricresyl phosphate (TCP) has been used as an anti-wear (AW) and extreme pressure (EP) additive with steel parts for the past 60 years [11][12][13][14][15][16]. It is now widely accepted that the effectiveness of TCP as an anti-wear additive is due to the chemical reaction of phosphorus with iron to form an iron phosphate film [15]. The tribofilms formed from TCP can control or reduce wear under boundary lubrications and thus prolong the life of systems.…”

Section: Introductionmentioning

confidence: 99%

Deactivation Effect of Tricresyl Phosphate (TCP) on Tribochemical Decomposition of Hydrocarbon Oil on a Nascent Steel Surface

et al. 2008

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A nascent surface has high activity to catalyze the decomposition of a lubricant under boundary lubrication conditions. To reduce the decomposition of a lubricant (multialkylated cyclopentane, MAC), tricresyl phosphate (TCP) was introduced as an additive. The tribological properties and decomposition process of lubricants on the nascent surface of bearing steel 52100 were investigated by a ball-on-disk friction tester in a vacuum chamber with a quadrupole mass spectrometer (Q-MS). The addition of TCP prolonged the induction period for decomposition of the lubricant. During the friction processes, hydrogen and gaseous hydrocarbons desorbed as tribochemical reaction products. XPS analysis revealed that the tribofilm from the additive was mainly composed of iron phosphate, which decreased the probability of generating a nascent surface, resulting in the reduction of desorption rate of gaseous products. The critical load for the mechanical activation of the decomposition correspondingly doubled.

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The influence of contact conditions on surface reaction layers formed between steel surfaces lubricated by an aviation oil

Cited by 12 publications

References 23 publications

Synergistic Effect of Nanodiamond and Phosphate Ester Anti-Wear Additive Blends

Synergistic Effect of Nanodiamond and Phosphate Ester Anti-Wear Additive Blends

Tribological Characteristics of Alkylimidazolium Diethyl Phosphates Ionic Liquids as Lubricants for Steel–Steel Contact

Deactivation Effect of Tricresyl Phosphate (TCP) on Tribochemical Decomposition of Hydrocarbon Oil on a Nascent Steel Surface

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