Magnesium Ferrite Promoting the Purity of Grown Boron Nitride Nanotubes

Abstract

The synthesis of boron nitride nanotubes via the boron oxide chemical vapor deposition process, especially when boron, magnesium oxide, and iron oxide are used as precursors for the synthesis, often encounters the problem of nanotubes doped with impurities, such as nanosheets and fibers. For this reason, this study adopts a novel active component of magnesium ferrite with a defined decomposition temperature and successfully synthesizes high-purity nanotubes. Growth experiments combined with computational fluid dynamics (CFD) simulations were performed to investigate the effects of active component ratio, growth temperature, ammonia flow rate, and boron source velocity on nanotube growth and the differences with that of magnesium oxide-iron oxide. Morphological analysis showed that the nanotubes grown from magnesium ferrite have better purity, effectively preventing the mixing of impurities in nanosheets and nanofibers. Furthermore, it was found that these nanotubes float at a more controlled height in a wider ammonia flow rate and temperature range. These allow for a more efficient collection of purer nanotube products for magnesium ferrite.