Abstract

The results of direct synthesis of boron nitride from boron powders of mean sizes of 0.05, 0.20, and 2.00 μm in nitrogen flow with impurity
of H2O in a xenon high-flux optical furnace are presented. Formation of equiaxed, plate-like powders and film-like structures of different
sizes was observed. The presence of moisture contributes to the formation of large film-like structures in BN powders from nanosized
boron. Carbon impurity in boron powder of mean size of 0.20 μm facilitates formation equiaxed nanosized powders of the smallest mean
size. High-temperature gradients in a xenon high-flux optical furnace results in the appearance of vibrations of w-BN at 1097-1107 cm−1
in
the FTIR spectra besides the h-BN vibrations of BN powders produced. The presence of moisture in nitrogen flow promotes formation of
new BN structures and other compounds as well. Vibrations belong to B-O-H bonds (1184-1193 cm-1
), N-B-O and B-O-B linkages (1107–
924 and ~ 700 cm−1
, respectively), and tetrahedral BO4 units in B2O3 could be detected in the FT-IR spectra of BN powders produced and
XRD studies confirmed that the produced BN powders contains significant amount of sassolite (H3BO3, boric acid) as well.

Key words: Boron nitride; moisture; structure; concentrated light heating; Fourier Transform Infrared Spectroscopy