Preparation, characterization, Raman, and terahertz spectroscopy study on carbon nanotubes, graphene nano-sheets, and onion like carbon materials

Abouelsayed, A.; Anis, Badawi; Hassaballa, Safwat; Khalil, Ahmed S. G.; Rashed, Usama M.; Eid, K. A.; Al-Ashkar, Emad A.; Hotaby, Walid El

doi:10.1016/j.matchemphys.2016.12.065

Cited by 26 publications

(6 citation statements)

References 54 publications

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“…Foram identificadas as bandas D e G com deslocamento Raman de 1367 e 1608 cm -1 , respectivamente. A banda D é relacionada aos grupos funcionais de oxigênio ligados as camadas de carbono, enquanto que a banda G é devido a hibridização sp 2 , relacionada aos materiais carbonosos [7]. A relação de intensidade entre as bandas D e G (ID/IG) é uma maneira de medir a quantidade de defeitos presente no GO, considerando que quanto maior o valor de ID/IG maior será a densidade de defeitos presentes na estrutura.…”

Section: Resultsunclassified

Compósitos Cobre-Grafeno Produzidos Por Metalurgia Do Pó Com Compactação a Frio

Faria¹,

Lima²,

Pinheiro³

et al. 2017

Anais Do Congresso Anual Da ABM

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Resumo Foram fabricados compósitos de matriz de cobre, reforçados com grafeno a partir da mistura de uma dispersão de óxido de grafeno com pó de cobre eletrolítico. A dispersão foi produzida pelo método de Hummers modificado e caracterizada por espectroscopia Raman e difração de raios X. Os compósitos foram fabricados pelo processo de metalurgia do pó convencional. Os pós de compósitos foram caracterizados por microscopia eletrônica de varredura, os corpos de prova consolidados foram avaliados quanto a densificação a verde e do corpo sinterizado, e os corpos sinterizados foram submetidos a ensaio de compressão a fim de verificar a resistência dos compósitos. Palavras-chave: Óxido de grafeno; Compósitos de matriz metálica; Metalurgia do pó.

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Section: Resultsunclassified

Compósitos Cobre-Grafeno Produzidos Por Metalurgia Do Pó Com Compactação a Frio

Faria¹,

Lima²,

Pinheiro³

et al. 2017

Anais Do Congresso Anual Da ABM

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“…It is still a matter of an ongoing debate whether the ultralow or superlow COF of OLC carbon films originates from surface passivation, lubrication from the as-formed graphene-like nanosheets during friction, or a rolling effect of spherical nanoparticles. , Nevertheless, it is reasonable to speculate that not only the intrinsic spherical structure but also the tribo-induced formation of interfacial nanostructures affects the frictional performances of OLC films. , In the present work, thick OLC films (∼1 μm) are capable of providing sufficient nanolubricants for the contact surface during sliding. Because of the relatively soft characteristics of the OLC film, materials transfer is supposed to occur along the heterogeneous interface, namely, detachment of the OLC nanoclusters from the film surface, which are then being transferred to the counterface surface.…”

Section: Discussionmentioning

confidence: 71%

“…It is still a matter of an ongoing debate whether the ultralow or superlow COF of OLC carbon films originates from surface passivation, 42 lubrication from the as-formed graphene-like nanosheets during friction, 43 or a rolling effect of spherical nanoparticles. 41,44 Nevertheless, it is reasonable to speculate that not only the intrinsic spherical structure but also the triboinduced formation of interfacial nanostructures affects the frictional performances of OLC films.…”

Section: Discussionmentioning

confidence: 99%

Tribochemical Behaviors of Onion-like Carbon Films as High-Performance Solid Lubricants with Variable Interfacial Nanostructures

Chen

Grützmacher

et al. 2019

ACS Appl. Mater. Interfaces

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Onion-like carbon (OLC), spherical nanoparticles consisting of carbon shells, is capable of providing exceptional lubrication effects. Nevertheless, the underlying mechanism, especially the tribo-induced evolution of interfacial nanostructures and their correlation with the friction states, is not clear. In this work, OLC films with a thickness of ∼1 μm were synthesized by electrophoretic deposition on the mirror-polished stainless steel. The lubricity was evaluated by tailoring the sliding aspects including applied normal load, contact time, and counterface materials. It is found that the friction reduction level is highly dependent on the material transfer and transformation of the OLC surface and the physicochemical nature of the as-formed tribolayer in the contact areas. The subsurface of the OLC film always undergoes a deep amorphization transformation upon sliding. It is interesting to note that the tribolayer formed on the bare steel ball is mainly composed of highly ordered graphene-like nanoflakes derived from the sliding-induced degradation of OLC nanospheres. In comparison, the nanospherical carbon structure can be retained in the topmost subsurface of the tribolayer formed on the ceramic Si3N4 ball. Such a nanosphere-/amorphization-coupled interface is capable of providing a robust lubrication state under high contact stresses. The findings identify a new lubrication mechanism for the spherical carbon nanostructure, rendering them effective solid lubricants.

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“…The first one is activated in the first order scattering process of sp 2 carbon nanostructures [ 44 ], and it is attributed to defects on the walls or disorder in graphitic materials [ 28 , 31 ], which disrupt or diminish the symmetry in the characteristic hexagonal arrangement in carbon allotropes with sp 2 hybridization. G band at approximately 1599 cm −1 has been related to the presence of the sp 2 phase of high crystalline graphitic structures (graphitic lattice mode E 2g ), the peak corresponds to tangential in-plane bond stretching of the sp 2 C–C atoms in hexagonal ring [ 45 , 46 , 47 ].…”

Section: Resultsmentioning

confidence: 99%

Multidimensional Nanocomposites of Epoxy Reinforced with 1D and 2D Carbon Nanostructures for Improve Fracture Resistance

2018

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A hybrid nanocomposites based on epoxy reinforced with a combination of 1D and 2D carbon nanomaterials for improving impact resistance are reported. Multi-walled carbon nanotubes and oxidized-multi-walled carbon nanotubes are used as 1D nanoreinforcements, and graphene derivative materials such as graphene oxide and reduced graphene oxide are utilized as 2D nanoreinforcements. In this research, the impact resistance of epoxy matrix reinforced with 1D or 2D and the mixture of both nanomaterials is studied. The research is focused on evaluation of the influence of adding different combinations of nanomaterials into epoxy resin and their Izod impact response. Moreover, fracture surface of nanocomposites is observed by scanning electron microscopy. Images show differences between the surfaces of brittle nature on thermoset epoxy polymer and tough nanocomposites. Synergy created with 1D and 2D nanomaterials produces stable dispersions in the processing, reflected in the interface. The interactions in nanocomposites are evidenced by infrared spectra, principally on the peaks related to oxygenated functional groups present in nanomaterials and absent in polymer matrix. Consequently, an increase of 138% in fracture strength of nanocomposites is exhibited, in comparison to the neat epoxy matrix. In addition, hybrid nanocomposites were synthesized in two different methods to evaluate the influence of manufacturing method on final properties of nanocomposites.

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Preparation, characterization, Raman, and terahertz spectroscopy study on carbon nanotubes, graphene nano-sheets, and onion like carbon materials

Cited by 26 publications

References 54 publications

Compósitos Cobre-Grafeno Produzidos Por Metalurgia Do Pó Com Compactação a Frio

Compósitos Cobre-Grafeno Produzidos Por Metalurgia Do Pó Com Compactação a Frio

Tribochemical Behaviors of Onion-like Carbon Films as High-Performance Solid Lubricants with Variable Interfacial Nanostructures

Multidimensional Nanocomposites of Epoxy Reinforced with 1D and 2D Carbon Nanostructures for Improve Fracture Resistance

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