Thermal properties of polymer‐derived ceramic reinforced with boron nitride nanotubes

We report the thermal properties of boron nitride nanotube (BNNT) reinforced ceramic composites using the polymer derived ceramic (PDC) processing route. The nano‐composites had a BNNT loading of up to 35.4 vol.%. TGA results showed that nano‐composites have good thermal stability up to 900°C in air. BNNTs in nano‐composites survived in an oxidizing environment up to 900°C, revealing that nano‐composites can be used for high temperature applications. Thermal conductivity of PDC reinforced with 35.4 vol.% BNNT was measured as 4.123 W/(m·K) at room temperature, which is a 2100 % increase compared to that of pristine PDC. The thermal conductivity value increases with the increase of BNNT content. A thermal conductivity percolation phenomenon appeared when the BNNT content increased to 36 ± 5 vol.%. The results of this study showed that BNNTs could effectively improve the thermal conductivity of PDC materials. BNNT reinforced PDC could be used as thermal structural materials in a harsh environment at temperatures up to 900°C.