Collaborative Research: Rare Earth Materials Under Extreme Conditions

稀土是一组广泛用于电池、手机、保护涂层和高熔点陶瓷的化学元素。它们的稳定性和适用性取决于它们的物理、电学、磁学和热力学性质，所有这些都与它们的结构密切相关。在NSF材料研究部门陶瓷计划的支持下，该项目将计算理论和实验结构和热力学测量结合在一起，以提供含氧，氮和碳的高熔点固体稀土化合物行为的基础数据和预测性理解。 实验由最先进的物理理论和机器学习对稳定性和结构的计算预测指导。高压被用作发现和合成新稀土材料的工具。 专门的高温量热技术测量热力学性质。热力学数据将存入数据库，供学术和工业科学家使用。 所获得的新知识使未来能够设计出更有效和更环保的含稀土元素的材料和设备。此外，学生通过该项目在各种技术培训，准备他们的职业生涯在许多领域，包括材料科学，陶瓷，半导体技术，和航空航天科学。技术摘要继续实验和计算科学家之间的长期合作，该项目，由美国国家科学基金会材料研究部陶瓷计划的支持，重点介绍了含稀土耐火陶瓷材料的热力学和结构性能。在高温高压下使用从头算热力学结合机器学习方法的计算将指导大气压和高压下的合成实验。高压样品在亚利桑那州立大学（ASU）的多砧装置中合成。 热力学性质由氧化物熔体溶液量热法、高温扫描量热法和滴捕量热法测定。用同步辐射衍射技术研究了高温相变。感兴趣的具体系统包括稀土一氧化物，碳氧化物和倍半氧化物，重点是它们在高温和高压下的结构和性能。将开发和传播一个热力学性质数据库。这样，热力学数据就可以存入数据库，供学术界和工业界科学家使用。 所获得的新知识使未来能够设计出更有效和更环保的含稀土元素的材料和设备。此外，通过该项目，学生们还将获得各种技术的培训，为他们在材料科学、陶瓷、半导体技术和航空航天科学等许多领域的职业生涯做好准备。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical summary Rare earths are a group of chemical elements used extensively in batteries, cell phones, protective coatings, and high melting ceramics. Their stability and suitability for such applications are governed by their physical, electrical, magnetic, and thermodynamic properties, all of which are closely related to their structure. With support from the Ceramics Program in NSF’s Division of Materials Research, this project brings together computational theory and experimental structural and thermodynamic measurements to provide fundamental data and predictive understanding of the behavior of high-melting solid rare earth compounds containing oxygen, nitrogen, and carbon. The experiments are guided by computational predictions of stability and structure made by state-of-the art physical theory and machine learning. High pressure is used as a tool to discover and synthesize new rare earth materials. Specialized high temperature calorimetric techniques measure thermodynamic properties. The thermodynamic data will be made available in a database for use by both academic and industrial scientists. The new knowledge obtained enables future design of more efficient and earth-friendly materials and devices containing rare earth elements. Additionally, students are trained through this project in a variety of techniques, preparing them for careers in many fields, including materials science, ceramics, semiconductor technology, and aerospace science.Technical summaryContinuing a long-standing collaboration between experimental and computational scientists, this project, supported by the Ceramics Program in NSF’s Division of Materials Research, focuses on the thermodynamic and structural properties of refractory rare earth containing ceramic materials. Computations using ab initio thermodynamics at high temperature and pressure combined with machine learning approaches will guide synthesis experiments at atmospheric and high pressures. High pressure samples are synthesized in a multi-anvil apparatus at Arizona State University (ASU). Thermodynamic properties are determined by oxide melt solution calorimetry, high temperature scanning calorimetry, and drop and catch calorimetry. High temperature phase transitions are studied by synchrotron diffraction techniques. Specific systems of interest include rare earth monoxides, oxycarbides, and sesquioxides, with emphasis on their structure and properties at high temperature and pressure. A database of thermodynamic properties will be developed and disseminated. Thereby thermodynamic data will be made available in a database for use by both academic and industrial scientists. The new knowledge obtained enables future design of more efficient and earth-friendly materials and devices containing rare earth elements. Additionally, students are trained through this project in a variety of techniques, preparing them for careers in many fields, including materials science, ceramics, semiconductor technology, and aerospace science.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.