Irfan Nadeem (Author), Matjaž Finšgar (Author), Goran Dražić (Author), Matjaž Malok (Author), Ardian Morina (Author), Mitjan Kalin (Author)

Abstract

Achieving macroscale superlubricity on engineering steel by utilizing aqueous green lubricants has gained growing interest, given its substantial potential to reduce energy consumption and carbon footprint. However, maintaining superlubricity under diverse sliding conditions over a prolonged duration is a major obstacle for real-scale applications. Herein, we report that a robust and durable tribofilm enabled by a unique lubrication mechanism based on carboxylated graphene quantum dots (CGQDs) in aqueous glycerol triggers macroscale superlubricity in self-mated steel contacts. A dedicated intermittent test was designed to show the superlubricity's robustness and the ability of the tribofilm to adapt to a variety of relevant sliding conditions. Moreover, the boundary film provides an average coefficient of friction of around 0.007 and up to 69 % wear reduction (compared to the base lubricant), resulting in the maintenance of superlubricity at a real final contact pressure of 123 MPa, which increases the upper limit of the contact pressure compared to current aqueous-lubricated steel contacts. The new superlubricity mechanism was enabled by the chemical adsorption of the CGQDs onto the worn metal surface, coupled with the tribo-induced structural degradation and transformation of the CGQDs into layered graphitic structures that generate an adaptable low-shear interface. This work provides new insights into the role of chemical adsorption and structural transformation of CGQDs in achieving superlubricity and is an important step forward for implementing energy-efficient and green lubrication technologies for industrial applications.

Keywords

grafenske kvantne pike;super mazljivost;mejno mazanje;vodni glicerol;zelena tribologija;jeklo;graphene quantum dots;superlubricity;boundary lubrication;aqueous glycerol;green tribology;steel;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL FS - Faculty of Mechanical Engineering
UDC: 539.92:621.8
COBISS: 196343811 Link will open in a new window
ISSN: 1873-3891
Views: 57
Downloads: 29
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Secondary language: Slovenian
Secondary keywords: grafenske kvantne pike;super mazljivost;mejno mazanje;vodni glicerol;zelena tribologija;jeklo;
Type (COBISS): Article
Pages: str. 1-16
Issue: ǂVol. ǂ 226, [article no.] 119226
Chronology: Jun. 2024
DOI: 10.1016/j.carbon.2024.119226
ID: 23769212