Comparative catalytic study on the carbothermic formation of hexagonal boron nitride with Li, Na, K and Ca carbonates

• Published in: Journal of materials science 2014, Vol.49 (1), p.371-379
• Main Authors: Çamurlu, H. Erdem, Gençer, Ahmet, Becer, Burcu
• Format: Article
• Language: English
• Subjects: Boron nitride; Boron oxides; Calcium carbonate; Carbonates; Carbothermic reactions; Catalysts; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Diffraction; Lithium; Materials Science; Particle size; Polymer Sciences; Potassium carbonate; Powders; Sodium carbonate; Solid Mechanics; Toy industry; X-rays
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-013-7714-x

Catalytic effects of Li, Na, K and Ca carbonates on carbothermic formation of hexagonal boron nitride (hBN) were investigated. Experiments were conducted by keeping the plain and catalyst added B 2 O 3  + C powder mixtures at 1400 °C in flowing nitrogen for 40–160 min. Products were subjected to quantitative and X-ray diffraction analyses, scanning and transmission electron microscopy examinations, and particle size measurements. Investigated catalysts increased the amount, particle size and crystallinity of the formed hBN. Average particle sizes of the obtained hBN powders were in 150–350 nm range. Catalytically, lithium and sodium carbonates were found to be the most effective, whereas calcium carbonate was the least effective. In the experiments conducted for 80 min, the quantity of the formed hBN increased 13-fold when 40 wt% Li 2 CO 3 was used, as compared to plain mixture. The increases were ninefold and fourfold for the same duration when 40 wt% K 2 CO 3 and 10 % CaCO 3 were used, respectively.