Few-layered-graphene - Si3N4 composite powders prepared by decomposition of methane onto a Si3N4 powder bed: Control of the average number of layers in the graphene stack

• Published in: Journal of the European Ceramic Society 2025-01, Vol.45 (1), p.116799, Article 116799
• Main Authors: Berrais, Adam, Weibel, Alicia, Mesguich, David, Turq, Viviane, Estournès, Claude, Laurent, Christophe
• Format: Article
• Language: English
• Subjects: Composites; Engineering Sciences; Graphene; Materials; Powders; Silicon nitride
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2024.116799

The chemical vapor deposition of carbon is performed onto a commercial silicon nitride powder bed. This produces few-layered-graphene (FLG) films or islands on the Si3N4 particles. The samples are characterized by several techniques including Raman spectroscopy, scanning and transmission electron microscopy. The experimental parameters of the methane (CH4) decomposition (temperature, CH4 concentration, dwell time) are correlated to the average number of graphene layers (N). Complete coverage of the Si3N4 particles is achieved for FLG with N controlled in the range 5–12, corresponding to 4–12 wt%. of carbon. Below that, for stacks with N = 3–4, the coverage of the surface by FLG islands is not total. The value found for the activation energy of CH4 conversion into carbon shows that island-growth is favored over layer-growth. A macroscopical method based on a carbon proportion evaluation gives an approximation of both the coverage ratio and the average number of layers in the stack. •Few-layered-graphene (FLG) deposited on the surface of Si3N4 particles, without any mixing and damaging the nanocarbons.•Complete coverage of the Si3N4 particles is achieved for FLG with the average number of graphene layers in the range 5-12.•Below that range, the Si3N4 particles are covered by FLG islands 3-4 layers thick.•The activation energy of CH4 conversion into carbon shows that island-growth is favored over layer-growth.•A macroscopical carbon content evaluation gives a good approximation of the coverage ratio and the average number layers.