One-step synthesis of few-layered-graphene/alumina powders for strong and tough composites with high electrical conductivity

•synthesis of few-layered-graphene/Al2O3 powders with carbon deposited as pristine FLG around α-Al2O3 grains•no manipulation of nanocarbons, simple to perform, prone to up-scaling, versatile•FLG film located along the grain boundaries of the submicron α-Al2O3 matrix and not dispersed as discrete par...

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Bibliographic Details
Published in:Journal of the European Ceramic Society 2020-12, Vol.40 (15), p.5779-5789
Main Authors: Weibel, Alicia, Flaureau, Andréas, Pham, Adeline, Chevallier, Geoffroy, Esvan, Jérôme, Estournès, Claude, Laurent, Christophe
Format: Article
Language:English
Subjects:
Alumina
Chemical Sciences
CVD
Engineering Sciences
Few-layered-graphene
Material chemistry
Materials
Mechanical and electrical properties
Nanocomposites
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Summary:•synthesis of few-layered-graphene/Al2O3 powders with carbon deposited as pristine FLG around α-Al2O3 grains•no manipulation of nanocarbons, simple to perform, prone to up-scaling, versatile•FLG film located along the grain boundaries of the submicron α-Al2O3 matrix and not dispersed as discrete particles•electrically conducting samples with a percolation threshold below 0.74 vol.% of carbon•samples stronger and similarly tough and hard than submicron α-Al2O3, showing crack-deflection and crack bridging The chemical vapor deposition of carbon onto a commercial α-Al2O3 powder bed produces a pristine film of few-layered-graphene (FLG) uniformly covering the α-Al2O3 grains. This obviates both the manipulation of nanocarbons, lengthy mixing steps and the risk of damaging any pre-existing graphene platelets. The powders are consolidated to 99 % by SPS, producing samples where a FLG film is located along the grain boundaries of the submicron α-Al2O3. Compared to the pure α-Al2O3, the composites are moderately stronger and similarly tough and hard due to crack-deflection and crack-bridging and they are electrically conducting with a percolation threshold below 0.74 vol.% of carbon. The high conductivity values reflect the high quality of the thin FLG film and its continuous nature over very long distances. The samples are characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy.
ISSN:0955-2219
1873-619X
DOI:10.1016/j.jeurceramsoc.2020.06.029