Superlubricity of Polyalkylene Glycol Aqueous Solutions Enabled by Ultrathin Layered Double Hydroxide NanosheetsShow others and affiliations
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. Vol. 11, no 22, p. 20249-20256
Keywords [en]
superlubricity, layered double hydroxide, nanoadditive, polyalkylene glycol, water-based, tribological properties
National Category
Other Mechanical Engineering
Research subject
Machine Elements
Identifiers
URN: urn:nbn:se:ltu:diva-74522DOI: 10.1021/acsami.9b03014ISI: 000470938500065PubMedID: 31083968Scopus ID: 2-s2.0-85066963361OAI: oai:DiVA.org:ltu-74522DiVA, id: diva2:1326543
Note
Validerad;2019;Nivå 2;2019-06-18 (johcin)
2019-06-182019-06-182025-02-14Bibliographically approved