Solid Solution and Isotope Effects on the Properties of Boride Ceramics

非技术描述：建议的研究将集中在硼化物陶瓷的基本热性能和氧化响应，如二硼化锆（ZrB2）。硼化物陶瓷能够承受极端的热、机械和化学环境，例如与高超音速飞行、先进的陶瓷切削工具、微电子电路的缓冲层和核反应堆的惰性基质燃料形式相关的环境。为了使未来系统的设计者能够充分利用难熔二硼化物和其他超高温陶瓷（UHTC）提供的独特组合性能，需要对热性能和氧化响应有更深入的了解。在商业产品中使用这些材料的能力将使系统在更高的温度下更可靠地运行，这将提高效率并降低能耗。技术细节：提出的努力的目标是了解高温热性能和难熔二硼化物陶瓷的环境响应。二硼化锆将作为一个代表性的系统，但研究也将包括其他二硼化物。这项研究的动机是相互矛盾和无法解释的热性能和氧化结果，这可能是由于在合成和加工过程中引入的杂质的数量和组成的变化。实验研究、基于物理的建模和分析表征相结合，将用于研究微量杂质、有意添加的固溶体和组成元素的同位素对热性质和氧化行为的作用。这项研究有可能改变人们对硼化物陶瓷的理解，使其能够在未来几代高超音速飞机、切割工具、电子设备或核反应堆中得到应用。该项目每年将培训两名研究生和至少一名本科生，学习极端环境下材料加工、测试和表征所需的专业技术。项目团队还将主要通过全州高中生数学和科学竞赛，向K-12学生推广科学和工程领域的潜在职业。

NON-TECHNICAL DESCRIPTION: The proposed research will focus on the fundamental thermal properties and oxidation response of boride ceramics such as zirconium diboride (ZrB2). Boride ceramics are capable of withstanding extreme thermal, mechanical, and chemical environments such as those associated with hypersonic flight, advanced ceramic-based cutting tools, buffer layers for microelectronic circuits, and inert matrix fuel forms for nuclear reactors. A deeper understanding of the thermal properties and oxidation response is needed to enable designers of future systems to fully utilize the unique combination of properties offered by refractory diborides and other ultra-high temperature ceramics (UHTC). The ability to use these materials in commercial products would allow systems to operate more reliably and at higher temperatures, which will increase efficiency and decrease energy consumption.TECHNICAL DETAILS: The goal of the proposed effort is to understand the elevated temperature thermal properties and environmental response of refractory diboride ceramics. Zirconium diboride will serve as a representative system, but the research will also encompass other diborides. The research is motivated by contradictory and unexplained thermal property and oxidation results, which may be due to variations in the amounts and compositions of impurities introduced during synthesis and processing. A combination of experimental studies, physics-based modeling, and analytical characterization will be used to investigate the roles of trace impurities, intentional solid solution additions, and the isotopes of the constituent elements on thermal properties and oxidation behavior. The research has the potential to transform the understanding of boride ceramics, which could enable their utilization in future generations of hypersonic aircraft, cutting tools, electronic devices, or nuclear reactors. The project will train two graduate students and at least one undergraduate per year in specialized techniques required for processing, testing, and characterizing materials for extreme environments. The project team will also promote potential careers in science and engineering to K-12 students, primarily through a statewide math and science competition for high school students.