Ultra-hard materials: New developments in c-Bn synthesis under high pressure conditions

Abstract

c-BN is a promoted material for different applications, such as tooling of ferrous alloys but also for future electronic devices. At the present time, due to the fact that boron nitride is a binary system and also to the elimination of the graphitic form, the preparation of c-BN thin film is difficult and not yet achieved. During these last six years, great efforts have been undertaken in the Laboratoire do Chimie du Solide du CNRS in order to improve the h-BN → c-BN flux assisted conversion using the HP-HT route. New fluxes with a nitrofluoride-composition have been developed in order: (i) to reduce the P, T experimental conversion conditions, (ii) to increase the conversion yield (h-BN → c-BN), (iii) to govern the average size of c-BN cristallites, (iv) to improve the crystal growth.

Now, new techniques have also been developed in the doping control of c-BN lattice.