Effect on the Joule heating properties of porous C/C composites by the addition of different types of carbon

Abstract

The functional properties of C/C composites have attracted increasing attention owing to their excellent electrical conductivity and thermal stability, which make them promising candidates for electrothermal materials. To investigate the influence of carbonaceous fillers on Joule heating and mechanical properties, three distinct filler types-graphite (GF), carbon powder (CP) and carbon black (CB) were added to wet-laid C/C composite sheets. Experimental results showed that the resistivity, tensile strength and electrothermal properties of C/C-GF were significantly improved compared with other materials. Due to the high crystallinity of GF, which was conducive to carrier transport, the resistivity of C/C-GF composite sheet was greatly reduced to 2.0789 Ω·m × 10⁻⁴. In addition, the unique structure of graphite not only reinforced the lamellar structure but also minimized sturctural defects. These combined effects resulted in an 80 % improvement in tensile strength of C/C-GF composite relative to the baseline material C/C-GF composite also had good performance in Joule heating performance. It could reach 140 °C in 70–80 s at 3 V voltage with a power density of 5.22 kW/m². This was due to the excellent performance of GF, which could generate more heat under the same conditions, and the heating efficiency was higher. In addition, it also exhibited excellent electrothermal behavior and good electrothermal stability in intermittent energized cycles and long-term service stability tests. Compared with commercially available polymer-based electrothermal films, C/C-GF composite emerges, as a high-performance alternative exhibiting higher steady-state temperature, improved temperature uniformity, and enchanced thermal stability. These advantages position this composite material as a promising solution for advanced electrothermal applications.