Thermal conductivity of vertically aligned boron nitride nanotubes

For the first time, we report the thermal conductivity of vertically aligned boron nitride nanotube (BNNT) films produced by catalytic chemical vapor deposition. High-quality BNNTs were synthesized at 1200 degrees C on fused silica substrates precoated with Pt thin-film thermometers. The thermal conductivity of the BNNTs was measured at room temperature by using a pulsed photothermal technique. The apparent thermal conductivity of the BNNT coatings increased from 55 to 170 W m(-1) K-1 when the thickness increased from 10 to 28 mu m, while the thermal conductivity attained a value as high as 2400 W m(-1) K-1. These results suggested that BNNTs, which are highly thermally conductive, but electrically insulating, are promising materials with unique properties. (C) 2016 The Japan Society of Applied Physics