The Research of the Synthesis Mechanism and Synthesis Process of High Crystallinity Globular h-BN

In this paper, by using polymer network different morphologies of hexagonal boron nitride (h-BN) was synthesized. Boric acid (H3BO3) and borax (Na2B4O7·10H2O) mix was used as a source of boron, and urea (CO(NH2)2) was used as a nitrogen source, for the preparation of high crystallinity globular h-BN. The experiment ensured the synthesis mechanism and the optimum synthesis process. The research showed that the synthesis mechanism of h-BN was that borax and boric acid were heated to decomposed into sodium oxide (Na2O) and boron oxide (B2O3). In flowing ammonia (NH3) atmosphere B2O3 transformed into h-BN again; with the increase of the synthesis temperature, h-BN crystallinity increased gradually. The optimum synthesis temperature of high crystallinity spherical h-BN was 800 °C. Graphitization index was 3.87 which was <5 and h-BN was in good crystallization range.