Super-low friction and wear in steel contacts enabled by tribo-induced structural degradation of graphene quantum dots

Nadeem, Irfan (avtor), Ambrožič, Bojan (avtor), Dražić, Goran (avtor), Kovač, Janez (avtor), Cavaleiro, Albano (avtor), Kalin, Mitjan (avtor)

Reducing friction is a promising strategy to decrease material losses and energy consumption in industrial systems. However, in aqueous-lubricated steel contacts, the contact pressure rarely exceeds 50 MPa during super-low friction due to excessive wear. This work demonstrates that even in steel/steel contacts, by combining graphene quantum dots (GQDs) with aqueous glycerol, it is possible to maintain super-low friction (µ ≈ 0.012) under a contact pressure as high as 316.5 MPa. Moreover, the use of GQDs improved the wear performance by 98 % compared to pure aqueous glycerol due to the formation of a tribochemical film, resulting from the electrostatic adsorption of GQDs on the positively charged sites on the worn surface. In particular, the exfoliation of graphene sheets within GQDs, the shearing of graphene layers inside the GQDs, and the OH–OH repulsion between the asperities shortens the running-in period and consequently reduces the friction and wear. At the same time, the formation of a chemically adsorbed tribofilm containing friction-induced structurally degraded GQDs protects the surface from wear and facilitates the maintenance of super-low friction at high contact pressures by improving the load-carrying capacity. This study suggests that green nano-lubricants based on GQDs have immense potential in sustainable engineering.

• Jezik: Angleški jezik
• Ključne besede: materials, graphene, quantum dots, tribology, friction, wear
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FS - Fakulteta za strojništvo
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2024
• Št. strani: 14 str.
• Številčenje: Vol. 244, art. 113111
• PID: 20.500.12556/RUL-159197
• UDK: 539.92
• ISSN pri članku: 0264-1275
• DOI: 10.1016/j.matdes.2024.113111
• COBISS.SI-ID: 200420867
• Datum objave v RUL: 03.07.2024

Gradivo je del revije

• Naslov: Materials & design
• Skrajšan naslov: Mater. des.
• Založnik: Scientific and Technical Press
• ISSN: 0264-1275
• COBISS.SI-ID: 10626075

Licence

• Licenca: CC BY-NC 4.0, Creative Commons Priznanje avtorstva-Nekomercialno 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by-nc/4.0/deed.sl
• Opis: Licenca Creative Commons, ki prepoveduje komercialno uporabo, vendar uporabniki ne rabijo upravljati materialnih avtorskih pravic na izpeljanih delih z enako licenco.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: materiali, grafen, kvantne pike, tribologija, trenje, obraba