High temperature ceramics and ultrahigh temperature ceramics are materials that typically have melting points above 2500-3000*C. These materials find important applications from grinding and cutting tools in machinery and mining industries to thermal insulation tiles, missile nozzles, and hypersonic vehicle leading edges in the aerospace industry. On the other hand, making these ceramic materials in the desired solid solution form will enable greater flexibility in optimizing their composition and mechanical, thermal, and chemical properties and should lead to further improved performance. This research aims to develop a scalable and economic method for the manufacturing of nano-sized ultrahigh temperature ceramic solid solution powders and provide fundamental new knowledge about the formation of such materials, especially at the nano-scale. The project will facilitate future industrial production of such important materials and advance related applications in different fields. It will also promote education and awareness in the advanced ceramics field at the institution and the broader South Florida region through various education, research, and engineering outreach activities.The central objective of the research award is to develop a low cost method for manufacturing nano-sized high temperature and ultrahigh temperature ceramic solid solution powders. The method is based on a high temperature spray pyrolysis technique that will incorporate rapid in situ carbothermal reduction reaction starting from soluble oxide and carbon precursors. An understanding of the fundamental composition-processing-structure interrelationships in the fabrication process will be obtained. The use of soluble precursors will lead to intimate mixing between oxide- and carbon-rich regions, which will help lower the carbothermal reduction reaction temperature and improve product uniformity. The adoption of spray pyrolysis at temperature higher than typically used will integrate the conventionally separate carbothermal reduction reaction as part of the spray pyrolysis process, enabling rapid, low cost, scalable production of nano-sized ceramic solid solution powders with controlled phase distributions and microstructures, all in one single step. The success of this project will not only provide an economic and scalable platform for the manufacturing of such important materials but also offer new insights about the fundamental impacts of various critical parameters from precursor chemistry and stoichiometry to processing conditions on the final phase composition, microstructure, and properties of nano-sized ceramic powders.
