Boron nitride is an element found in the periodic table. It is a chemical element with similar atomic radii to nitrogen and carbon, and it has a relatively high melting point. However, it has a number of structural forms. Boron nitride nanotubes (BNNTs) can be formed by a series of complex chemical reactions.
Controlling the BNNT self-assembly process is important for the quality of BNNT material. Several factors contribute to this process, including the amount of heat supplied to the boron feedstock and the temperature distribution of the boron melt. Supplemental sources of heating may be used to control the temperature of the boron melt and BNNT self assembly region.
Using a Direct Induction concentrator (DI) to supply supplemental heat to the boron feedstock is an energy efficient and low-cost method for producing a boron nitride nanotube. Additional heat can be provided by a direct laser beam, electric arcs, or supplemental lasers.
The initial boron feedstock is heated to a temperature that makes it electrically conductive. This is done through either a Direct Induction coil or a crucible. After the feedstock is heated, it is placed in the Direct Induction chamber. If the crucible is used, the gas in the crucible can be cooled using a water-cooled copper crucible.
After the desired operating pressure has been achieved, the boron nitride melt is initiated. Nitrogen gas is then fed into the chamber through an opening in the crucible. When the boron nitride melting point is reached, the gas is dissolved in the boron melt.