Bulk and Interface Bonding in Ceramics and Intermetallics

陶瓷和金属间化合物中的本体键合和界面键合

• 批准号: 9412146
• 负责人: John Spence
• 金额: $ 27.6万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-15 至 1999-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9412146&HistoricalAwards=false
• 关键词: Bulk; Interface; Bonding; Ceramics; Intermetallics

Spence 9412146 A three year program of research is proposed of atomic bonding in crystals, at interfaces and at defects. Ceramics and intermetallic compounds will be studied using a combination of ab-initio quantum molecular dynamics computations, self-consistent calculations and experimental measurements of bond charge distributions by quantitative convergent beam electron diffraction method. The Zeiss Omega energy-filtering electron microscope at the Arizona State University center for High Resolution Electron Microscopy will be used for the experimental work. Principal Investors propose a new technique based on the specular electron beam reflected from a metal-ceramic interface in the transmission geometry for reflection imaging, microanalysis and bonding studies of buried interfaces. This work is collaborative with C.P. Flynn. For perfect crystals, in which bonds have been "seen" for the first time only recently, Principal Investors propose bond charge distribution measurements in titanium-aluminum and a series of ionic crystals in order to test the accuracy of self-consistent computations based on the local density approximation. Measured bond distributions will be compared for titanium-aluminum with and without manganese doping, which is found to reduce brittleness. In ferroectric crystal Principal Investigators plan comparisons of charge transfer between titanium and oxygen in strontium titanate and isostructural barium titanate oxygen in order to understand why one is ferroelectric and the other not. %%% The proposed research seeks to investigate the origins of atomic bonding in crystals, at interfaces and defects. Ceramics and intermetallic compounds will be studied using a combination of theoretical calculations and experimental measurements of bond charge distributions by quantitative techniques. ***

斯宾塞9412146 提出了一个三年计划，研究晶体中的原子键合，界面和缺陷。 陶瓷和金属间化合物将使用从头算量子分子动力学计算，自洽计算和实验测量的定量会聚束电子衍射方法的键电荷分布的组合进行研究。 亚利桑那州立大学高分辨率电子显微镜中心的蔡司欧米茄能量过滤电子显微镜将用于实验工作。 主要投资者提出了一种新的技术，基于镜面电子束从金属陶瓷界面反射的透射几何反射成像，微观分析和埋界面的键合研究。 这项工作是与C.P.弗林合作。 对于完美晶体，其中的键最近才首次被“看到”，主要投资者提出了钛铝和一系列离子晶体中的键电荷分布测量，以测试基于局域密度近似的自洽计算的准确性。 测得的键分布将比较钛铝锰掺杂和不掺杂，这被发现，以减少脆性。 在铁电晶体中，主要研究人员计划比较钛酸锶和同结构钛酸钡氧中钛和氧之间的电荷转移，以了解为什么一个是铁电体而另一个不是。 拟议的研究旨在调查晶体中原子键合的起源，界面和缺陷。 陶瓷和金属间化合物将使用理论计算和实验测量结合键电荷分布的定量技术进行研究。 ***