Synthesis of boron nitride from BCNO

DOI: 10.62564/M4-OP1515

Peter Sylenko, Galyna Oleinyk, Oleksii Pokropyvnyi, Olesya Pylypchuk, Anstoliy Danylenko, Yuriy Solonin

Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine


Boron nitride is well known as material for sythesis analogous of carbon fullerenes, nanotubes, and fullerites [1], as well as new phases. Hexagonal boron nitride (h-BN) has a complex of high performance such as high values of chemical stability and thermal conductivity, good electrical insulation and and lubricating properties, good ability to absorb neutrons. Due to its properties, h-BN is a multifunctional material, it is used to produce cubic boron nitride (c-BN), as high-temperature lubricants and coatings, when creating ceramic composite materials and the like. The h-BN powder is produced by various methods, one of the most common being the reaction of boric acid and melamine [2]. It was shown [3], that the formation of h-BN from boric acid and melamine occurs in the following sequence: first, the BCNO phase (at 350 °C and above) is formed, and with the synthesis temperature up to 800 °C and above in the BCNO phase also found h-BN. The objective of this work was to study the structure formation of BN with BCNO. The synthesis was carried out in a tubular flow quartz reactor at a temperature of 1200 °C in a stream of nitrogen [4]. The obtained samples were examined by transmission electron microscopy and X-ray phase analysis. The powder is composed of flat nanostructured particles. Particle sizes are 1-1.5 microns, and the sizes of the nanoscale substructure elements contained in them are in the range of 20-50 nm. Moreover, the smallest (20-30 nm) substructure elements have a rounded shape, while the largest ones are mainly polyhedral cut. According to Х-ray phase analysis, the sample consists of a hexagonal graphite-like phase of boron nitride. Analysis of microelectron diffraction patterns (MEGs) obtained from the powder confirms this result. However, a comparison of the features of 002 and 100 diffraction reflections in the form of rings on the MEG suggests that the sample also contains rhombohedral boron nitride.

Keywords
BN, h-BN, synthesis, X-ray analysis

Acknowledgments
Not provided

References
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