In-situ TEM Heating Studies of Nanoscale and Submicron Sized Ceramic Oxide Powders (Engineering)

初步研究了100-300 nm MgO烟雾颗粒单晶块的原位加热行为，结果表明，两个烧结单晶块之间形成的颈部的稳定性与颗粒的接触几何形状直接相关。本研究项目是最初MgO立方体研究的逻辑延伸。它将集中于以下目标：确定在真空加热的亚微米尺寸的MgO单晶立方体中负责质量输运的具体机制；纳米级、单晶、球形陶瓷氧化物颗粒的聚结和材料输运的原位TEM加热研究；纳米颗粒大阵列的原位加热研究并进行了原位加热研究，考察了烧结气氛对颈部形貌和稳定性的影响。在初步研究中观察到的颈部不稳定性以前从未被观察或预测过。这项研究将加深我们对这一现象的理解，进一步的原位实验可能会对细颗粒的烧结产生更多的新见解。在主办机构的互动活动包括：组织和教授两门新课程（一门课程将通过检查块状和薄膜玻璃来研究非结晶固体，另一门课程将是基于材料科学主题的非工程师工程/技术调查课程）；并作为女大学生组织“女性科学与工程”的讨论领袖参与其中。该项目进一步推进了VPW计划的目标，即(1)为女性提供在工程和NSF支持的科学学科中发展职业的机会；(2)通过为在工业、政府和学术机构工作的女性科学家和工程师提供更大的知名度，鼓励女性在科学和工程领域追求职业。通过鼓励妇女参与科学，这是对国家未来科学活力的宝贵投资。

A preliminary study of the insitu heating behavior of single- crystal cubes of 100-300 nm MgO smoke particles has shown that the stability of neck formed between 2 sintering single-crystal cubes is directly related to the contact geometry of the particles. This research project is a logical extension of the initial MgO cube study. It will focus on the following objectives: determination of the specific mechanism(s) responsible for mass transport in vacuum heated, sub-micron-sized MgO single crystal cubes; insitu TEM heating studies of coalescence and material transport in isolated pairs of nanoscale, single crystal, spherical particles of ceramic oxides; insitu heating studies of larger arrays of nanoscale particles; and exsitu heating studies to examine the effects of the sintering atmosphere on neck morphology and stability. The neck instabilities observed in the preliminary studies have never before been observed or predicted. This research will develop our understanding of this phenomena, and further insitu experiments are likely to lead to additional new insights into the sintering of fine particles. Interactive activities at the host institution include: organizing and teaching two new courses (one course will study noncrystalline solids by examining both bulk and thin-film glasses, and the other course will be an engineering/technology survey course for non- engineers, based on materials science topics); and participation as a discussion leader in Women in Science and Engineering, an organization for women undergraduates. This project furthers VPW program objectives which are (1) to provide opportunities for women to advance their careers in engineering and in the disciplines of science supported by NSF and (2) to encourage women to pursue careers in science and engineering by providing greater visibility for women scientists and engineers employed in industry, government, and academic institutions. By encouraging the participation of women in science, it is a valuable investment in the Nation's future scientific vitality.