In-situ synthesis of TiN and TiB2 compounds during reactive spark plasma sintering of BN–Ti composites

Abstract

A BN-TiB2-TiN composite was produced via reactive sintering of the hexagonal BN (hBN) with 20 wt% Ti. Spark plasma sintering (SPS) was used as the fabrication method and the sample was characterized by X-ray diffractometry, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. According to the results, the Ti was utterly consumed during the SPS, led to the in-situ TiB2 and TiN0.9 formations. Additionally, the microstructural study revealed the nucleation and growth of new hBN platelets from the initial fine hBN particles. Anyway, the final composite reached a relative density of 95%, because of the remaining free spaces between the hBN platelets. It was found that some nitrogen and boron atoms could leave the TiN and TiB2 microstructures, respectively, and diffuse into the opposing phase.