Boron nitride nanotubes: Pronounced resistance to oxidation

Boron nitride (BN) nanotubes have the same nanostructure as carbon nanotubes but are found to exhibit significant resistance to oxidation at high temperatures. Our systematic study has revealed that BN,nanotubes are stable at 700degreesC in air and that some,thin nanotubes (diameter less than 20 nm) with perfect multiwalled cylindrical structure can survive up to 900degreesC. Thermogravimetric analysis reveals an onset temperature for oxidation of BN nanotubes of 800degreesC compared with only 400degreesC for carbon nanotubes under the same. conditions. This more pronounced resistance of BN nanotubes to oxidation is inherited from the hexagonal BN and also depends on the nanocrystalline structure. This high level of resistance to oxidation allows promising BN nanotube applications at high temperatures. (C) 2004 American Institute of Physics.