BNNT Fiber for Hypersonic Applications

Reinforcement of monolithic non-oxide ceramics requires non-oxide fiber.  The leading candidate material is made of boron nitride nanotubes (BNNTs), which have exceptional RF transparency and strength at high temperatures.  A previous project, now concluding, has demonstrated proof-of-concept of BNNT fibers (BNNTf) using our high purity BNNT material, capability of initial production, and scalability.  We will pick up where that work left off, ambitiously seeking to improve every step along the supply chain.  In this proposal, we will enhance production and purification of high quality BNNT feedstock, advance processes for dispersing BNNT, improve dimensions and characteristics of BNNTf, and thoroughly characterize BNNTf, prioritizing electrical properties at high temperature and at frequency ranges of interest for hypersonics.  The fiber will then be applied to multi-layer composites for high-temperature applications where monolithic non-oxide ceramics fail, notably hypersonic aerospace.