Nanotech 2010

Synthesis of a New Class of Boron Nitride Nanotubes via the Pressurized Vapor/Condenser Method

M.W. Smith, K. Jordan
NASA Langley Research Center, US

Keywords: nanotubes, boron nitride nanotubes

Abstract:

Researchers have long been able to make nanotubes out of carbon, but have struggled to craft them from boron nitride. Carbon nanotubes (CNT’s) and boron nitride nanotubes (BNNT’s) have approximately the same strength, but BNNT’s can survive temperatures that are twice as high as those of CNT’s - 800°C and higher. To date, only high-quality BNNT’s on the order of a micrometer in length have been created; larger versions have been riddled with defects in the crystalline structure. Recently, researchers at the NASA Langley Research Center working in collaboration with the Thomas Jefferson National Accelerator Laboratory have created the first high-quality, uniformly crystalline BNNT’s in large quantities. The resultant nanotubes are long enough to be spun into usable yarn. To perform the fabrication, a CO2 laser is focused on a boron-containing target in a chamber filled with nitrogen. Laser heating creates a plume of boron gas that rapidly rises in the chamber. A cooled metal wire is then inserted into the boron gas, causing the gas to cool and condense into liquid droplets. The droplets then combine with the nitrogen to self-assemble into BNNT’s. The reaction is extremely fast and creates very long nanotubes over a span of a few milliseconds. The BNNT’s created from the reaction exhibit excellent strength, piezoelectric, conductivity, and stability properties at high temperature. The new fabrication method is an enabling technology for the development of large quantities of BNNT’s that can be used in a myriad of aerospace, automotive, and medical applications. This poster will highlight details of the fabrication method and show examples and properties of the resultant nanotubes.
 
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