Aligned carbon nanotube/carbon (CNT/C) composites with exceptionally high electrical conductivity at elevated temperature to 400 °C

Abstract

To obtain a high electrical conductivity for aerospace and defense applications, in this paper, we investigated the electrical properties of carbon nanotube reinforced carbon (CNT/C) composites at elevated temperature up to 400 °C in air. The CNT/C composites were made of aligned CNT sheet and pyrolytic carbon (PyC) by chemical vapor infiltration (CVI) process. The electrical conductivity of the aligned CNT/C composites is 3.2 × 106 S · m−1 in room temperature and shows a positive temperature dependence as a function of the measuring temperature, and the conductivity reaches to the order of ∼107 S · m−1 at 400 °C. We concluded that the conduction in the aligned CNT/C composite is mainly dominated by the tunneling conductivity mechanism. These unique features are related to the structural change of composites by infiltrating amorphous PyC into the space in between of the CNT bundles. The exceptionally high conductivity might be contributed to the electron transport mechanism between the CNT bundles and the PyC matrix.