A self-propagation high-temperature synthesis and annealing route to synthesis of wave-like boron nitride nanotubes

Large quantities of boron nitride (BN) nanotubes were synthesized by annealing a catalytic boron-containing porous precursor in flowing NH3 gas at 1180 °C. The porous precursor was prepared by self-propagation high-temperature synthesis (SHS) method at 800 °C using Mg, B2O3 and amorphous boron powder (α-B) as the starting materials. The porous precursor played an important role in large quantities synthesis of BN nanotubes. The as-synthesized product was characterized by X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), Raman, Scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), Transmission electron microscopy (TEM) and High-resolution transmission electron microscopy (HRTEM). Characterization results indicated that the BN nanotubes displayed wave-like inner structures with diameters in the range of 50–300 nm and average lengths of more than 10 μm. The possible growth mechanism of the BN nanotubes was also discussed.

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► Large quantities of wave-like BN nanotubes were synthesized by SHS-annealing method.
► The catalytic boron-containing porous precursor was produced by self-propagation high-temperature synthesis method.
► Three growth models were proposed to explain the growth mechanism of the wave-like BN nanotubes.