CAREER: Oxygen Transport in Heterogeneous, Nonoxide Ceramics - Toward Durable New Composite Constituents

职业：异质非氧化物陶瓷中的氧传输 - 开发耐用的新型复合材料

• 批准号: 1944557
• 负责人: David Poerschke
• 金额: $ 55.5万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1944557&HistoricalAwards=false
• 关键词: CAREER; Oxygen; Transport; Heterogeneous; Nonoxide

NON-TECHNICAL DESCRIPTION: Strong, tough, and lightweight ceramic composites based on carbides, borides, and nitrides can enable new high performance and energy efficient transportation and energy conversion technologies including turbine engines, hypersonic vehicles, and solar-thermal energy systems. However, in-service reactions with oxidizing species such as oxygen and water vapor can significantly reduce the durability of these materials at high temperatures. This degradation is particularly problematic when the penetration of the oxidizing species into the material occurs in an unpredictable way due to local variability or defects in the material structure originating during the manufacturing process. This project addresses this challenge by developing new experimental and modeling approaches to systematically understand how oxidizing species are transported within these heterogeneous ceramic microstructures. These insights are used to understand the reasons that some state-of-the art materials perform better than others, while parallel efforts leverage this understanding to accelerate the discovery of new materials and processing pathways to achieve improved performance. The undergraduate and graduate students trained as part of this program will find employment in industries supporting aerospace and defense technology development.TECHNICAL DETAILS: This project combines experiments and modeling to understand how microstructural heterogeneities in single-and multi-phase nonoxide ceramics impact oxidant transport mechanisms, and how the resulting spatial variations in internal oxygen activity impact local oxidation reactions at the transition between diffusion- and reaction-controlled processes. New experimental tools including embedded chemical markers and solid-state electrochemical oxygen pumps and sensors are being developed to support these objectives. The program is initially focusing on crystalline Si, SiC, and SiC-C systems and Si-(O)-C polymer derived ceramics (PDC). Insights about the behavior of these systems is then being applied to discover advanced PDCs, active fillers, and multi-principal element borides and carbides offering superior high temperature performance. This research directly impacts efforts to address many critical societal challenges at a point in time when development of many systems is impeded by inferior material performance and durability at higher temperatures and in more extreme environments. This work is especially timely given the current industrial interest in implementing ceramic composites in commercial products. The efforts is also working to fill the pipeline of next-generation STEM leaders by developing a ceramic science outreach program for high school students that builds interest in the ceramic sciences through connections to the ceramic arts, and by implementing writing-based assignments in the materials science curriculum to improve retention of underrepresented students with broader interests and verbal abilities.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.

非技术描述：基于碳化物、硼化物和氮化物的坚固、坚韧和轻质陶瓷复合材料可以实现新的高性能和节能运输和能量转换技术，包括涡轮发动机、高超音速飞行器和太阳能热能系统。然而，在使用中与氧化物质（如氧气和水蒸气）的反应会显著降低这些材料在高温下的耐久性。当氧化物质以不可预测的方式渗透到材料中时，由于制造过程中产生的材料结构的局部变化或缺陷，这种降解尤其成问题。该项目通过开发新的实验和建模方法来系统地了解氧化物质如何在这些异质陶瓷微结构中运输，从而解决了这一挑战。这些见解被用来理解一些最先进的材料比其他材料性能更好的原因，而并行的努力利用这种理解来加速新材料和加工途径的发现，以实现改进的性能。作为该计划一部分的本科生和研究生将在支持航空航天和国防技术发展的行业找到工作。技术细节：本项目将实验和建模相结合，以了解单相和多相非氧化陶瓷的微观结构异质性如何影响氧化剂的传输机制，以及由此产生的内部氧活性的空间变化如何影响扩散控制和反应控制过程之间过渡的局部氧化反应。为了支持这些目标，正在开发新的实验工具，包括嵌入式化学标记和固态电化学氧泵和传感器。该项目最初专注于晶体Si、SiC和SiC- c系统以及Si-(O)- c聚合物衍生陶瓷（PDC）。对这些体系行为的深入了解，将被用于发现先进的pdc、活性填料、多主元素硼化物和碳化物，这些都能提供卓越的高温性能。这项研究直接影响了解决许多关键社会挑战的努力，因为在更高温度和更极端环境下，许多系统的发展受到劣质材料性能和耐久性的阻碍。鉴于目前工业对在商业产品中实现陶瓷复合材料的兴趣，这项工作尤其及时。通过为高中生开发陶瓷科学外展项目，通过与陶瓷艺术的联系建立对陶瓷科学的兴趣，以及在材料科学课程中实施写作作业，以提高代表性不足的学生对更广泛的兴趣和语言能力的保留，努力填补下一代STEM领导者的管道。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。