LEAPS-MPS: Exploring Centrifugal Jet Spinning of Ultra-High-Temperature Ceramic Nanofibers

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公共法律117-2)。非-技术描述：该研究项目包括一种制造微米和纳米尺寸陶瓷纤维的新方法，这种纤维可以承受数千摄氏度而不熔化。一种金属盐和一种聚合物被溶解，形成粘性溶液，然后纺丝成纤维。然后对纤维进行热处理，使金属与聚合物中的碳反应，形成超高温陶瓷纤维。研究了高温和气氛中氧气对纤维微观结构的影响。这项研究使得有可能在低温下大量地制造以纤维形式得不到的化合物的陶瓷纳米纤维垫。这些超高温陶瓷纤维垫可用于热防护系统，使飞机、导弹和火箭以更快的速度和更长的时间以高超声速飞行。来自一家少数民族服务机构的两名本科生和两名研究生正在获得陶瓷制造和测试方面的实验室经验。另有8至16名本科生从事陶瓷材料表征设备的设计、制造和测试。毕业生通常在高科技行业找到工作或进一步攻读研究生学位。技术细节：目前有几种合成方法可以制备过渡金属碳化物纳米晶纳米颗粒、纳米棒、纳米粉末和纳米线；然而，使用可扩展的技术来制备长而连续的超高温过渡金属碳化物纳米纤维用于大规模生产仍然是一个巨大的挑战。本课题以离心式喷气纺丝法制备的聚合物前驱体纳米纤维为原料，采用碳热还原法制备了新型过渡金属碳化物纳米纤维。离心式喷射纺丝使用离心力从溶液中生产纤维，其速度和成本与熔喷和玻璃纤维方法相似，并在该项目中用于利用高能效的聚合物前驱体合成方法，同时还具有易于大规模生产的可扩展的额外好处。并对纤维的氧化行为进行了研究。本项目所获得的知识对大量制备其他陶瓷纤维具有一定的参考价值。此外，这项研究为未被充分代表的群体的本科生和研究生提供了在材料科学和工程方面的实践经验。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).NON-TECHNICAL DESCRIPTION: This research project consists of a novel method to fabricate micro- and nano-sized ceramic fibers that can withstand several thousand degrees Celsius without melting. A metal salt and a polymer are dissolved to make a viscous solution that is subsequently spun into fibers. The fibers are then heat treated to react the metal with the carbon in the polymer and form the ultra-high-temperature ceramic fiber. The effects of high temperatures and oxygen in the atmosphere on the fibers’ microstructure are also studied. This research makes it possible to fabricate, in large quantities and at low temperature, ceramic nanofiber mats of compounds not available in fiber form. These ultra-high temperature ceramic fiber mats can contribute to thermal protection systems that allow aircraft, missiles, and rockets to travel faster and for a longer period at hypersonic speed. Two undergraduate students and two graduate students from a minority-serving institution are obtaining laboratory experience in ceramic manufacturing and testing. Another 8 to 16 undergraduate students are engaged in designing, fabricating, and testing equipment for ceramic materials characterization. Graduates typically find employment in the high-tech industry or further pursue graduate degrees.TECHNICAL DETAILS: Several synthesis methods exist for the fabrication of transition metal carbide nanocrystalline nanoparticles, nanorods, nano-powders, and nanowires; however, it is still a great challenge to fabricate long and continuous ultra-high-temperature transition metal carbide nanofibers using scalable techniques for mass production. In this project, novel transition-metal carbide nanofibers are fabricated by the carbothermal reduction of polymer precursor nanofibers manufactured by centrifugal jet spinning. Centrifugal jet spinning uses centrifugal forces to produce fibers from solutions at speeds and costs similar to melt-blown and glass fiber methods and is used in this project to leverage the energy-efficient polymer precursor synthesis method with the added benefit of being easily scalable for mass production. The oxidation behavior of the fibers is also investigated. The knowledge obtained from this project can be useful to fabricate other ceramic fibers in large quantities. In addition, this research provides opportunities for undergraduate and graduate students of underrepresented groups to obtain hands-on experience in materials science and engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.