SBIR Phase I: The Digital Spinneret

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This Small Business Innovation Research Phase I project will determine optimal process parameters for massively parallel Laser Chemical Vapor Deposition (LCVD) of silicon carbide fibers by building on work already performed at the proposing company, Rensselaer Polytechnic Institute, and the University of Montreal. Ceramic fibers are typically produced using polymeric precursors, which means that stoichiometrically pure fibers are almost impossible to attain, limiting (usually severely) their potential performance in the demanding applications they are intended for. Our direct LCVD production method for pure fibers produces high purity monofilaments in a single "extrusion microtube", but commercial scale-up requires a sea change in manufacturing approach. Phase I research will investigate the parameters involved in creating a "Digital Spinneret" (DS) that grows many fibers at once. The DS approach provides the fiber stability and growth conditions found in microtubes with the opportunity to grow hundreds or thousands of pure fibers at a time. By creating a DS test bed platform, the Phase I research will identify the conditions under which such fibers may be grown on a DS, including precursor gas mixtures, laser power and geometry, and fiber geometry, while also providing inputs to an engineering path toward massive parallelization. The broader impact/commercial potential of this project is quite large, as it bears directly on scaled production of high purity ceramic fibers. While the near-term focus is on SiC fibers for turbo machinery, the technology developed will be applicable to fibers of any material where standard CVD has been successful, such as boron and boron carbide in armor and high strength-to-weight structures, tungsten carbide for tooling/ wear, and magnesium diboride for superconducting wires. The markets for high performance fibers include military and aerospace (turbo machinery, rockets, advanced structures), automobile, biomedical, energy, and other industries that require advanced materials with exceptional strength, stiffness, heat resistance and/or chemical resistance. These are fast-growing fiber markets with great potential, the collective size of which exceeds $1 billion. The energy footprint of parallelized LCVD is 1/1000th that of competing methods because energy is only used where needed - in the fiber growth region - and precursor waste is minimized as well. This provides huge cost and environmental advantages over standard production methods. This platform technology is largely material-agnostic, decoupling development costs from specific materials. Finally, successful development of high-performance-fiber capacity at scale solves the problem of domestic supply, an issue of considerable national concern.