Further insights into the electrical and thermal properties of carbon enriched silicon oxycarbide composites

[摘要] Cheap, abundant and easily-obtained carbon fillers such as graphite (GR), carbon black (CB), lamp black and active carbon were successfully incorporated into a silicon oxycarbide (SiOC) matrix using attrition milling followed by spark plasma sintering to obtain dense crack-free bulk composites. Carbon-enriched SiOC composites (C-SiOC) showed enhanced electrical (sigma) and thermal (k) conductivities. Values as high as 667 Sm-1 for sigma and an increase of 63% for k compared with SiOCs were obtained when GR flakes were incorporated into the SiOC. Very interesting values were also achieved (250 Sm-1 and a 46% increase) when CB was used, due to the formation of a percolating network of highly-interconnected tortuous graphene-like carbon domains which promoted phonon/electron transport. Raman parameters such as the tortuosity index, 3D ordering of graphene layers and the I-2D/I-G ratio, in conjunction with AB stacking, were crucial for understanding the electronic and/or phonon transport. (C) 2021 The Authors. Published by Elsevier B.V. CC_BY_4.0

[发布日期] 2021-12-31

[关键词] Composite materials;Nanostructured materials;Sintering;Microstructure;Scanning electron microscopy (SEM);Transmission electron microscopy (TEM)