chapter  19
Preparation and Application of Long Boron Nitride Nanotubes
ByYuanlie Yu, Hua Chen, Yun Liu, Lu Hua Li, and Ying (Ian) Chen
Pages 26

Long BNNTs were synthesized using an optimized ball milling and annealing process. In a typical process, amorphous boron (B) powder was rst loaded into a stainless steel milling jar with steel balls (25.4 mm in diameter AISI 420) under NH3 atmosphere at 300 kPa. e weight ratio of the steel balls to B powder is 50:1. e ball milling process was performed for 50 h at a rotation speed of 300 rpm. is milling process introduces about 1.5 at% iron nanoparticles homogeneously to the B powder. e milled powder was then annealed at 1100°C in a tube furnace in an N2 ow of 100 mL/min. After annealing for 15 h, a large amount of long BNNTs was produced.