Synthesis of highly ordered hBN in presence of group I/IIA carbonates by solid state reaction

• Published in: Crystal research and technology (1979) 2016-06, Vol.51 (6), p.380-392
• Main Authors: Öz, Muhammed, Saritekın, Namık Kemal, Bozkurt, Çetin, Yildirim, Gürcan
• Format: Article
• Language: English
• Subjects: Boron nitride; Carbonates; Characterization; Crystallization; Fourier transforms; Hexagonal boron nitride; Infrared spectroscopy; Metal carbonates; Nanocrystals; Nanotubes; Scanning electron microscopy; SEM and TEM; Transmission electron microscopy
• ISSN: 0232-1300; 1521-4079
• DOI: 10.1002/crat.201500337

This comprehensive study declares experimentally the effects of IA/IIA metal carbonates on the formation of hexagonal boron nitride (hBN) with the aid of the available experimental methods as regards Fourier transform infrared spectroscopy (FT‐IR), powder X‐ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (TEM). hBN is synthesized in the existence of the metal carbonates at the low temperature by modified O'Connor method. The experimental findings of FT‐IR and XRD investigations show that the addition of metal carbonates affects considerably the crystallization of hBN powder during the synthesis process. The presence of the high concentration level of the additions improves harshly the crystallinity. In this respect, the graphitization index deduced from the XRD patterns reduces with the enhancement in the amount of the dopant content. At the same time, the differentiation between the products is analyzed by the SEM surveys. According to the results, the materials synthesized by the Li2CO3 powder exhibit both the tubular form and rod‐like while the other samples prepared by the CaCO3 chemical dopant display the homogeneous plates. Even, the TEM images confirm the nanowires and nanotubes structures such as multi‐walled cylindrical, bamboo nanotubes in all the materials studied in this work. Crystallization of highly ordered hexagonal boron nitride nanocrystals synthesized with IA/IIA metal carbonates at the low temperature via modified O'Connor method improves considerably with the increment in concentration level of metal carbonate. In fact, the hBN pepared by Li2CO3 powder exhibits the best crystallinity, smoothest and densest surface morphology with finest connectivity between the grains.