20.500.12556/RUL-159197 Super-low friction and wear in steel contacts enabled by tribo-induced structural degradation of graphene quantum dots 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. materials graphene quantum dots tribology friction wear superlubricity super-low friction wear-resistance aqueous glycerol green tribology materiali grafen kvantne pike tribologija trenje obraba true false true Angleški jezik Slovenski jezik Članek v reviji 2024-07-03 07:52:49 2024-07-03 07:52:51 2025-02-03 13:26:53 0000-00-00 00:00:00 2024 0 0 14 str. Vol. 244, art. 113111 Aug. 2024 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 539.92 0264-1275 10.1016/j.matdes.2024.113111 200420867 1-s2.0-S0264127524004854-main.pdf 1-s2.0-S0264127524004854-main.pdf 1 F9C503AC5BB71B3182DA10D685229864 078f3967ea318598c609f65e1172fd91c30541ef9d2da6b4dcf829d571a0e729 1825db18-dfbd-11ef-b232-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=198996 https://www.sciencedirect.com/science/article/pii/S0264127524004854 0 583aac73-3901-11ef-a3da-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=187142 Fakulteta za strojništvo 0 0 0