ORCID Profile
0000-0002-2815-6002
Current Organisation
University of Wollongong
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Publisher: Elsevier BV
Date: 09-2018
Publisher: Springer Science and Business Media LLC
Date: 07-01-2021
DOI: 10.1007/S40544-020-0464-2
Abstract: The rapid development of molecular dynamics (MD) simulations, as well as classical and reactive atomic potentials, has enabled tribologists to gain new insights into lubrication performance at the fundamental level. However, the impact of adopted potentials on the rheological properties and tribological performance of hydrocarbons has not been researched adequately. This extensive study analyzed the effects of surface structure, applied load, and force field (FF) on the thin film lubrication of hexadecane. The lubricant film became more solid-like as the applied load increased. In particular, with increasing applied load, there was an increase in the velocity slip, shear viscosity, and friction. The degree of ordering structure also changed with the applied load but rather insignificantly. It was also significantly dependent on the surface structure. The chosen FFs significantly influenced the lubrication performance, rheological properties, and molecular structure. The adaptive intermolecular reactive empirical bond order (AIREBO) potential resulted in more significant liquid-like behaviors, and the smallest velocity slip, degree of ordering structure, and shear stress were compared using the optimized potential for liquid simulations of united atoms (OPLS-UAs), condensed-phase optimized molecular potential for atomic simulation studies (COMPASS), and ReaxFF. Generally, classical potentials, such as OPLS-UA and COMPASS, exhibit more solid-like behavior than reactive potentials do. Furthermore, owing to the solid-like behavior, the lubricant temperatures obtained from OPLS-UA and COMPASS were much lower than those obtained from AIREBO and ReaxFF. The increase in shear stress, as well as the decrease in velocity slip with an increase in the surface potential parameter ζ, remained conserved for all chosen FFs, thus indicating that the proposed surface potential parameter ζ for the COMPASS FF can be verified for a wide range of atomic models.
Publisher: MDPI AG
Date: 30-06-2020
DOI: 10.3390/LUBRICANTS8070070
Abstract: Nowadays, the increasing demand to reduce energy consumption and improve process reliability requires an alternative lubricant with an effective tribological performance and environmentally friendly properties to replace traditional lubricants in hot steel manufacturing. The current work reviews recent comprehensive experimental and theoretical investigations in a new generation of alkaline-based glass lubricants, with phosphate, borate, and silicate being intensively researched. This class of lubricants showed an outstanding friction reduction, anti-wear, and anti-oxidation performance on coupled steel pairs over a wide range of temperatures (from 650 °C to 1000 °C). Each type had different tribochemical reactions within itself and with oxidized steel surfaces, which were largely determined by their chemical nature. In addition, the critical role of each structural component was also determined and corroborated by computational simulation. The theoretical studies at quantum and atomic levels reinforced our experimental findings by providing insights into the reaction mechanism using the static and dynamic simulations of the adsorption of lubricant molecules onto iron oxide surfaces. Additionally, the new reactive molecular dynamics (MD) model developed for alkali phosphate will need to be extended further to consider the realistic operating conditions of these lubricants at the atomic scale.
Publisher: Informa UK Limited
Date: 24-08-2020
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 08-2021
Publisher: Informa UK Limited
Date: 15-03-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8RA04658A
Abstract: The involvement of sodium induces dramatic transformation in lubrication potentials of boron oxide melt.
Publisher: American Chemical Society (ACS)
Date: 03-11-2017
Publisher: Elsevier BV
Date: 02-2020
Publisher: Elsevier BV
Date: 02-2018
Publisher: Springer Science and Business Media LLC
Date: 30-08-2017
DOI: 10.1038/S41598-017-09879-7
Abstract: Understanding how an adaptive integrated interface between lubricant additives and solid contacts works will enable improving the wear and friction of moving engine components. This work represents the comprehensive characterization of compositional and structural orientation at the sliding interface from the perspective of surface/interface tribochemistry. The integrated interface of a lubricant additive-solid resulting from the friction testing of Graphite-like carbon (GLC) and PVD-CrN coated rings sliding against cast iron under boundary lubrication was studied. The results indicate that in the case of the CrN/cast iron pair the antiwear and friction behavior were very strongly dependent upon lubricant. In contrast, the tribology of the GLC surface showed a much lower dependence on lubrication. In order to identify the compounds and their distribution across the interface, x-ray microanalysis phase mapping was innovatively applied and the principle of hard and soft acids and bases (HSAB) to understand the behaviour. Phase mapping clearly showed the hierarchical interface of the zinc-iron polyphosphate tribofilm for various sliding pairs and different sliding durations. This interface structure formed between lubricant additives and the sliding surfaces adapts to the sliding conditions – the term adaptive interface. The current results help explain the tribology of these sliding components in engine.
Publisher: American Chemical Society (ACS)
Date: 25-06-2022
DOI: 10.1021/ACS.LANGMUIR.2C01022
Abstract: In this work, several phosphate-intercalated Mg-Al layered double hydroxides (LDHs) were synthesized and evaluated as solid lubricant additives in polyalphaolefin (PAO-4) by means of tribotesting on coupled GCr15/cast iron contacts. The effects of test parameters such as normal loads, additive concentrations, and substrate surface roughness were investigated, while the LDH crystal structure received considerable attention. Several types of structural disorder after anion exchange were identified based on X-ray diffraction (XRD) analysis. The unstable structures promote feasible shearing during sliding to improve friction and wear. In addition, antiwear properties correlate well with the anion charge number or the quantity of anion in the interlayer region. Overall, the tribological performance increased in the order HPO
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2CP01601J
Abstract: The exfoliation of layered double hydroxide (LDH) is promoted as the basal spacing expands when PO 4 3− is converted to HPO 4 2− . Thin sheets of Mg–Al–oleate transferred direct contact to sliding contact, which significantly reduced friction and wear.
Publisher: Elsevier BV
Date: 09-2022
Publisher: American Chemical Society (ACS)
Date: 27-09-2021
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 10-2016
Publisher: American Chemical Society (ACS)
Date: 21-01-2021
Publisher: Elsevier BV
Date: 2020
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 12-2017
Publisher: Elsevier BV
Date: 08-2019
Publisher: Elsevier BV
Date: 03-2020
No related grants have been discovered for Bach Tran.