ORCID Profile
0000-0002-7347-4317
Current Organisation
University of Leeds
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Publisher: Wiley
Date: 17-06-2020
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 11-2021
Publisher: MDPI AG
Date: 08-2023
DOI: 10.3390/LUBRICANTS11080327
Abstract: To comply with the high demand for efficient and sustainable lubrications, carbon-based tribofilms and/or nanomaterials have emerged as a potential solution that can resolve the current major shortcomings of phosphorus- and sulphur-rich tribofilms and protective coatings. Although their employment is still in the early stages of realization and research, these tribofilms receive significant interest due to their capability to continuously and in situ repair/replenish themselves during sliding, which has been an ultimate goal of all moving mechanical systems. Structurally, these tribofilms are complex and predominantly amorphous or disordered with/without graphitic domains (e.g., graphene/graphite, onion-like carbon, etc.). Chemically, the compositions of these tribofilms vary significantly with environments, conditions, and material precursors. Yet, the structural properties of carbon-based tribofilms remain largely ambiguous, which precludes a full understanding of the mechanisms underlying the formation and lubrication performance. This review will summarize the current state-of-art research about the in situ carbon-based tribofilms that have been published since the pioneering works. Particularly, this work will highlight the recent approaches to generate these tribofilms, their associated lubrication performance, current understanding of the formation mechanics, common analytical approaches for these tribofilms, and the compatibility of these tribofilms with other additives. Together, the overall outlooks will be drawn, demonstrating the knowledge gaps and proposing further investigation tactics to tackle these emerging issues.
Publisher: Elsevier BV
Date: 06-2021
Publisher: Wiley
Date: 24-08-2023
Abstract: Lead mixed‐halide perovskites offer tunable bandgaps for optoelectronic applications, but illumination‐induced phase segregation can quickly lead to changes in their crystal structure, bandgaps, and optoelectronic properties, especially for the Br–I mixed system because CsPbI3 tends to form a non‐perovskite phase under ambient conditions. These behaviors can impact their performance in practical applications. By embedding such mixed‐halide perovskites in a glassy metal‐organic framework, a family of stable nanocomposites with tunable emission is created. Combining cathodoluminescence with elemental mapping under a transmission electron microscope, this research identifies a direct relationship between the halide composition and emission energy at the nanoscale. The composite effectively inhibits halide ion migration, and consequently, phase segregation even under high‐energy illumination. The detailed mechanism, studied using a combination of spectroscopic characterizations and theoretical modeling, shows that the interfacial binding, instead of the nanoconfinement effect, is the main contributor to the inhibition of phase segregation. These findings pave the way to suppress the phase segregation in mixed‐halide perovskites toward stable and high‐performance optoelectronics.
Publisher: American Chemical Society (ACS)
Date: 18-12-2020
Publisher: American Chemical Society (ACS)
Date: 18-06-2020
Publisher: Elsevier BV
Date: 06-2019
Publisher: American Chemical Society (ACS)
Date: 28-07-2021
Publisher: MDPI AG
Date: 31-03-2021
DOI: 10.3390/LUBRICANTS9040035
Abstract: The increasing demand for low-viscosity engine oil has underscored the role of zinc dialkyldithiophosphates (ZDDP) as a conventional anti-wear and antioxidant additive. It is essential to investigate the influence of modern additives such as cyclopropanecarboxylic acid (CPCa) and Ni nanoparticles on the tribological performance of ZDDP for practical commercial oil application. According to the experimental results, Ni nanoparticles formed a protective film that exhibited a synergistic effect with ZDDP. A significantly higher concentration of sulphur in the tribofilm was detected compared to ZDDP by itself, which was responsible for a 27.6% lower wear loss. Meanwhile, a competitive effect between CPCa and ZDDP resulted in a dramatic increase in friction and unstable anti-wear performance. This was demonstrated by a localized formation of the ZDDP tribofilm on the wear surfaces after the friction test. These results have highlighted the synergistic and competitive effects of emerging additives (CPCa and Ni nanoparticles) in the ZDDP tribofilm formation between the sliding steel contacts. This further suggests a new approach to increase the efficiency of ZDDP’s tribological performance at cold start-up processes.
Publisher: Wiley
Date: 09-08-2019
Publisher: American Chemical Society (ACS)
Date: 24-08-2022
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: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 12-2020
DOI: 10.1007/S40544-020-0455-3
Abstract: A comparative evaluation of the friction and wear behaviors of 40CrNiMoA steel and Inconel 718 alloy sliding against Si 3 N 4 counterparts was conducted over a large temperature range from room temperature (RT) to 800 °C. The temperature-dependent tribological properties associated with the resulting chemical mitigation and structural adaptation of the solid sliding surface were clarified by surface/interface characterizations. The results revealed desirable performance in reducing friction and wear at elevated temperatures, which was associated with the resulting oxide composite film’s adaptive lubricating capability, whereas severe abrasive wear occurred at room/ambient temperatures. The oxidative-abrasive differentials for the two alloys were further discussed by considering the combined effect of temperature and stressed-shearing conditions.
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 07-2015
Publisher: American Chemical Society (ACS)
Date: 03-02-2021
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 12-2023
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 07-2019
Publisher: Elsevier BV
Date: 05-2016
Publisher: ASME International
Date: 04-07-2023
DOI: 10.1115/1.4062738
Publisher: Springer International Publishing
Date: 2020
Publisher: Elsevier BV
Date: 10-2020
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2021
End Date: 2024
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2020
End Date: 2020
Funder: Australian Research Council
View Funded ActivityStart Date: 2019
End Date: 2022
Funder: Australian Research Council
View Funded Activity