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Wang, Hongdong
Publications (2 of 2) Show all publications
Wang, H., Liu, Y., Guo, F., Sheng, H., Xia, K., Liu, W., . . . Luo, J. (2020). Catalytically Active Oil-based Lubricant Additives Enabled by Calcining Ni-Al Layered Double Hydroxides. Journal of Physical Chemistry Letters, 11, 113-120
Open this publication in new window or tab >>Catalytically Active Oil-based Lubricant Additives Enabled by Calcining Ni-Al Layered Double Hydroxides
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2020 (English)In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 11, p. 113-120Article in journal (Refereed) Published
Abstract [en]

Layered double hydroxides (LDHs) have lately been hailed as robust lubricant additives for improving tribological properties and as ideal catalysts for synthesizing carbon-based nanomaterials. In this paper, in situ analytical tools are used to track the evolution of the crystal structure and chemical composition of LDHs during calcination. Nickel oxide and elemental nickel can be produced by calcining NiAl-LDH in air (LDH-C-Air) and argon (LDH-C-Ar), respectively. For the base oil with 1 wt % LDH-C-Air, negligible wear can be detected even after a 2 h friction test under a severe contact pressure (∼637 MPa). A relatively thick tribofilm (∼60 nm) with a better mechanical property is formed, which protects the solid surface from severe wear. In addition, the possible formed carbon debris may also prevent the direct collision of asperities and effectively improve the wear resistance. This work provides a unique vision for the application of calcined LDHs with the combination of catalysis and tribology.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2020
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-77248 (URN)10.1021/acs.jpclett.9b03094 (DOI)000506088000018 ()
Note

Validerad;2020;Nivå 2;2019-12-23 (svasva)

Available from: 2019-12-23 Created: 2019-12-23 Last updated: 2020-03-04Bibliographically approved
Wang, H., Liu, Y., Liu, W., Wang, K., Li, J., Ma, T., . . . Luo, J. (2019). Superlubricity of Polyalkylene Glycol Aqueous Solutions Enabled by Ultrathin Layered Double Hydroxide Nanosheets. ACS Applied Materials and Interfaces, 11(22), 20249-20256
Open this publication in new window or tab >>Superlubricity of Polyalkylene Glycol Aqueous Solutions Enabled by Ultrathin Layered Double Hydroxide Nanosheets
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2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 22, p. 20249-20256Article in journal (Refereed) Published
Abstract [en]

It was previously proved that the existence of a large amount of hydrogen ions in water-based lubricants can easily lead to a superlubric state; however, it was also shown that these hydrogen ions could cause severe corrosion. As part of a large family of attractive clays, layered double hydroxides (LDHs) possess excellent tribological properties in water-based lubrication systems. In the present work, two different kinds of LDHs are dispersed in polyalkylene glycol (PAG) aqueous solutions, in two distinct forms: ultrathin nanosheets (ULDH-NS) of ca. 60 nm wide and ca. 1 nm thick (single or double layer) and nanoparticles (LDH-NP) of ca. 19.73 nm wide and ca. 8.68 nm thick. We find that the addition of ULDH-NS greatly shortens (as much as 85%) the running-in period prior to reaching the superlubricity regime and increases the ultimate load-bearing capacity by about four times. As compared to the fluid film thickness of the lubricating PAG solution, their ultrathin longitudinal dimension will not impair or influence the fluid film coverage in the contact zone. The analysis of sliding solid surfaces and the atomic force microscope microscale friction test demonstrate that the adsorption of ULDH-NS enables the sliding solid surfaces to be polished and protected because of their relatively weak interlayer interaction and increased adhesion effect. Owing to their superior tribological properties as lubricant additives, ultrathin LDH nanosheets hold great potential for enabling liquid superlubricity in industrial applications in the future.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
superlubricity, layered double hydroxide, nanoadditive, polyalkylene glycol, water-based, tribological properties
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-74522 (URN)10.1021/acsami.9b03014 (DOI)000470938500065 ()31083968 (PubMedID)2-s2.0-85066963361 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-18 (johcin)

Available from: 2019-06-18 Created: 2019-06-18 Last updated: 2019-07-01Bibliographically approved
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