Combustion Synthesis of Silicon Carbide for Advanced Ceramics

超纯细小颗粒是生产高性能先进陶瓷产品的理想原料。AeroChem之前已经证明了由反应物硅烷和联氨燃烧合成氮化硅产品。在本项目中，将研究碳化硅的燃烧合成。所使用的火焰燃烧器与常规的碳氢化合物-空气火焰研究中使用的相同，并且火焰外观非常相似。两个主要区别是，在碳化硅(或氮化物)的火焰合成中不使用氧气，主要产品是粉末，必须从同流的产物气体中分离出来。在目前的研究中，AeroChem将研究在这种平焰燃烧器上通过硅烷和乙炔反应制备碳化硅。这里的主要问题是形成没有硅或碳污染物的纯碳化硅产品。热力学计算表明，这可以通过在接近化学计量比的狭窄反应物比范围内操作来实现，在该范围内，以硅烷为原料计算碳化硅的产率为100%。将继续进行实验和进一步的理论分析，以证实确实可以以接近100%的成品率生产高纯度的碳化硅产品。高质量的碳化硅粉末在烧结或热压制备先进陶瓷材料方面有着巨大的潜在市场。目前先进陶瓷的生产进展受到美国制造的高质量粉末供应不足的限制。此外，本课程将开发的燃烧合成技术和理解将适用于各种其他所需材料的燃烧合成。

Fine, ultrapure particles are desirable starting materials for production of high-performance advanced ceramic products. AeroChem has previously demonstrated the combustion synthesis of silicon nitride products from the reactants silane and hydrazine. In this program, combustion synthesis of silicon carbide will be investigated. The flav-flame burner to be used is the same as used in conventional hydrocarbon-air flame studies, and the flame appearance is quite similar. Two major differences are that no oxygen is used in the flame synthesis of silicon carbide (or nitride) and the major product is a powder which must be separated from the coflowing product gases. In the current study, AeroChem will investigate the preparation of silicon carbide via reaction of silane with acetylene on this flat-flame burner. The major issue here is the formation of a pure silicon carbide product without the presence of either silicon or carbon contaminants. Thermodynamic calculations indicate that this can be achieved by operation in a narrow reactant ratio range near stoichiometric, where the yield of silicon carbide is calculated to be 100% based on the silane feed. Experiments and further theoretical analysis will be pursued to confirm that a high-purity SiC product can indeed be produced at close to 100% yield. High quality silicon carbide powders have a large potential market in the preparation of advanced ceramic materials via sintering or hot pressing. Present progress in production of advanced ceramics is currently limited by the unavailability of a US-made high quality powder. In addition, the technology and understanding of combustion synthesis which will be developed in this program will be applicable to combustion synthesis of a wide variety of other desirable materials.