Turbostratic boron nitride consolidated by SPS

Abstract

Turbostratic boron nitride (t-BN) powder prepared by mechanical grinding of hexagonal boron nitride (h-BN) under the nitrogen atmosphere with the oxygen concentration less than 1 ppm was consolidated by spark plasma sintering (SPS). The turbostratic structure was maintained after the consolidation, which was characterized by XRD, Raman and IR spectra. The t-BN consolidated without any additives at 1900°C for 10 min under applied pressure of 100 MPa showed a bulk density of 95%. The bending strength, Young's modulus and Shore hardness of the consolidated t-BN were 72 MPa, 259 GPa and 117 Hs, respectively. They were much higher than those of conventionally consolidated h-BN. On the other hand, the thermal conductivity was 3 W/mK and much lower than the compact of h-BN.