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Tribological performance of Graphene/Carbon nanotube hybrid reinforced Al2O3 composites.

Yazdani B, Xu F, Ahmad I, Hou X, Xia Y, Zhu Y - Sci Rep (2015)

Bottom Line: Benchmarked against the pure Al2O3, the composite reinforced with a 0.5 wt% GNP exhibited a 23% reduction in the friction coefficient along with a promising 70% wear rate reduction, and a hybrid reinforcement consisting of 0.3 wt.% GNPs + 1 wt.% CNTs resulted in even better performance, with a 86% reduction in the wear rate.The wear mechanisms for the composites were analysed based on the mechanical properties, brittleness index and microstructural characterizations.GNPs played the important role in the formation of a tribofilm on the worn surface by exfoliation; whereas CNTs contributed to the improvement in fracture toughness and prevented the grains from being pulled out during the tribological test.

View Article: PubMed Central - PubMed

Affiliation: College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK.

ABSTRACT
Tribological performance of the hot-pressed pure Al2O3 and its composites containing various hybrid contents of graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) were investigated under different loading conditions using the ball-on-disc method. Benchmarked against the pure Al2O3, the composite reinforced with a 0.5 wt% GNP exhibited a 23% reduction in the friction coefficient along with a promising 70% wear rate reduction, and a hybrid reinforcement consisting of 0.3 wt.% GNPs + 1 wt.% CNTs resulted in even better performance, with a 86% reduction in the wear rate. The extent of damage to the reinforcement phases caused during wear was studied using Raman spectroscopy. The wear mechanisms for the composites were analysed based on the mechanical properties, brittleness index and microstructural characterizations. The excellent coordination between GNPs and CNTs contributed to the excellent wear resistance property in the hybrid GNT-reinforced composites. GNPs played the important role in the formation of a tribofilm on the worn surface by exfoliation; whereas CNTs contributed to the improvement in fracture toughness and prevented the grains from being pulled out during the tribological test.

No MeSH data available.


Related in: MedlinePlus

XRD patterns of the Al2O3 with and without GNP additions.
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f2: XRD patterns of the Al2O3 with and without GNP additions.

Mentions: The typical peaks of α-Al2O3 were shown in all nanocomposites samples in their XRD profiles (Fig. 2), without any detectable carbide phases, indicating no significant reactions between the GNPs and the Al2O3 during the consolidation process. At high GNP contents, an additional peak appeared at 26.3° for S2-0, which became more detectable for S5-0. This peak corresponds to the basal plane in crystalline graphite, and its appearance suggests that the GNPs remained undamaged and kept their integrity after the hot-pressing. When the GNP contents are higher than 2%, the platelet structure makes the reflection from the (002) planes dominant and is easily detectable by XRD.


Tribological performance of Graphene/Carbon nanotube hybrid reinforced Al2O3 composites.

Yazdani B, Xu F, Ahmad I, Hou X, Xia Y, Zhu Y - Sci Rep (2015)

XRD patterns of the Al2O3 with and without GNP additions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477330&req=5

f2: XRD patterns of the Al2O3 with and without GNP additions.
Mentions: The typical peaks of α-Al2O3 were shown in all nanocomposites samples in their XRD profiles (Fig. 2), without any detectable carbide phases, indicating no significant reactions between the GNPs and the Al2O3 during the consolidation process. At high GNP contents, an additional peak appeared at 26.3° for S2-0, which became more detectable for S5-0. This peak corresponds to the basal plane in crystalline graphite, and its appearance suggests that the GNPs remained undamaged and kept their integrity after the hot-pressing. When the GNP contents are higher than 2%, the platelet structure makes the reflection from the (002) planes dominant and is easily detectable by XRD.

Bottom Line: Benchmarked against the pure Al2O3, the composite reinforced with a 0.5 wt% GNP exhibited a 23% reduction in the friction coefficient along with a promising 70% wear rate reduction, and a hybrid reinforcement consisting of 0.3 wt.% GNPs + 1 wt.% CNTs resulted in even better performance, with a 86% reduction in the wear rate.The wear mechanisms for the composites were analysed based on the mechanical properties, brittleness index and microstructural characterizations.GNPs played the important role in the formation of a tribofilm on the worn surface by exfoliation; whereas CNTs contributed to the improvement in fracture toughness and prevented the grains from being pulled out during the tribological test.

View Article: PubMed Central - PubMed

Affiliation: College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK.

ABSTRACT
Tribological performance of the hot-pressed pure Al2O3 and its composites containing various hybrid contents of graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) were investigated under different loading conditions using the ball-on-disc method. Benchmarked against the pure Al2O3, the composite reinforced with a 0.5 wt% GNP exhibited a 23% reduction in the friction coefficient along with a promising 70% wear rate reduction, and a hybrid reinforcement consisting of 0.3 wt.% GNPs + 1 wt.% CNTs resulted in even better performance, with a 86% reduction in the wear rate. The extent of damage to the reinforcement phases caused during wear was studied using Raman spectroscopy. The wear mechanisms for the composites were analysed based on the mechanical properties, brittleness index and microstructural characterizations. The excellent coordination between GNPs and CNTs contributed to the excellent wear resistance property in the hybrid GNT-reinforced composites. GNPs played the important role in the formation of a tribofilm on the worn surface by exfoliation; whereas CNTs contributed to the improvement in fracture toughness and prevented the grains from being pulled out during the tribological test.

No MeSH data available.


Related in: MedlinePlus