Synthesis of polycrystalline boron nitride nanotubes with Lead(II) oxide and Iron(III) nitrate nonahydrate as promoters

Boron nitride nanotubes (BNNTs) possess many fascinating properties that make them promising for various applications in microelectronics, biomedicine and coating. In this work, BNNTs were synthesized by a ball milling-annealing method. Boron powder was milled with promoters, lead(II) oxide (PbO) and iron(III) nitrate nonahydrate (Fe(NO 3 ) 3 ⋅9H 2 O), under the N 2 gas environment to prepare a precursor. Then, bamboo-like and cylindrical BNNTs were synthesized by annealing the precursor at 1150 °C under the NH 3 gas environment. The phase of the BNNTs was identified to be hexagonal BN by X-ray diffractometry, Raman spectroscopy and transmission electron microscopy . The effect of the promoter content in the precursor on the synthesis of the BNNTs was investigated. When the mass ratio of B:PbO:Fe(NO 3 ) 3 ⋅9H 2 O was 1:1:1, bamboo-like and cylindrical BNNTs with a diameter of 60–500 nm, uniform composition and polycrystalline microstructure were obtained.