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。它们在这些应用中的稳定性和适用性是由它们的物理、电、磁和热力学性质决定的，所有这些性质都与它们的结构密切相关。在美国国家科学基金会材料研究部陶瓷项目的支持下，该项目将计算理论与实验结构和热力学测量结合起来，为含氧、氮和碳的高熔点固体稀土化合物的行为提供基础数据和预测理解。实验以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为指导。高压是发现和合成稀土新材料的重要手段。专门的高温量热技术测量热力学性质。热力学数据将在一个数据库中提供，供学术界和工业界的科学家使用。获得的新知识使未来设计更高效、更环保的含有稀土元素的材料和设备成为可能。此外，学生们通过这个项目接受各种技术的培训，为他们在许多领域的职业生涯做好准备，包括材料科学、陶瓷、半导体技术和航空航天科学。该项目由美国国家科学基金会材料研究部陶瓷项目支持，延续了实验和计算科学家之间的长期合作，重点研究含稀土耐火陶瓷材料的热力学和结构特性。高温高压下的从头算热力学计算结合机器学习方法将指导大气和高压下的合成实验。在亚利桑那州立大学（ASU）的多砧装置中合成了高压样品。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。用同步加速器衍射技术研究了高温相变。特别感兴趣的系统包括稀土氧化物、碳化物和倍半氧化物，重点是它们在高温高压下的结构和性质。将开发和传播热力学性质数据库。因此热力学数据将在数据库中提供，供学术界和工业界的科学家使用。获得的新知识使未来设计更高效、更环保的含有稀土元素的材料和设备成为可能。此外，学生们通过这个项目接受各种技术的培训，为他们在许多领域的职业生涯做好准备，包括材料科学、陶瓷、半导体技术和航空航天科学。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。

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.