On the choice of hexagonal boron nitride for high pressure phase transformation using the catalyst solvent process

The degree of three-dimensional ordering, particle-size distribution and purity of two types of hexagonal boron nitride have been studied with a view to establish any possible correlation between these characteristics with the conversion of hexagonal form to cubic phase at high pressure and high temperature using magnesium as the catalyst solvent. The crystalline phases formed at high pressure and high temperature have been studied and the dependence of degree of graphitization of boron nitride and purity on the cubic boron nitride conversion discussed. Diffraction patterns, Photomicrographs. 18 ref.--AA