EAGER - Nanoscale 3D Imaging of ice-embedded metallic structures

技术摘要：以高空间和化学分辨率成像金属-水体系的可能性将提供关于界面现象的独特和关键信息，这些界面现象控制着催化和结构合金系统在使用条件下的行为和降解。现有的解决这些问题的方法目前集中在开发能够提供实时信息的原位瞬变电磁保持器或光谱学技术。然而，这些技术通常缺乏将界面现象量化到原子水平所必需的空间和化学分辨率。该项目的目标是开发一种独特的方法，分别通过加州大学伯克利分校和密歇根大学独特的冷冻制备和冷冻成像能力，在三维和纳米尺度上对金属/水界面进行成像。它涉及到从适合于原子探针断层扫描(APT)检查的冰样制备样品的发展；聚焦离子束(FIB)研磨是样品制备方法的选择。提出的方法的高回报在于该方法的多功能性，它不仅允许研究金属-水系统，而且还适用于硬材料和软材料之间的界面。非技术概述：该项目将开发一种对冻结的固液界面进行成像的新技术。首先，微型针将从冰冻的标本中加工出来。其次，冻结的针头将被逐个原子分析，以形成局部化学和原子排列的3D图像。这项技术将能够分析对许多科学和工业技术非常重要的固液界面。例如，这项技术可以解决对合金开发很重要的腐蚀现象，由于缺乏像这里建议的那样的高分辨率表征技术，目前只能在现象学水平上了解这些现象。预计这些方法将影响与能源材料(如发电厂结构材料、电池材料、催化用纳米颗粒和有机电子器件)开发相关的大量研究领域。综合研究和教育计划将雇用一名或多名本科生与一名博士后研究人员合作，并利用现有的大学项目，强调招聘女性和代表性不足的少数族裔。

TECHNICAL SUMMARY: The possibility of imaging metal-water systems at high spatial and chemical resolution would provide unique and critical information on the interfacial phenomena controlling the behavior and degradation of catalytic and structural alloy systems while under service conditions. Existing approaches to these questions currently focus on developing in-situ TEM holders or spectroscopy techniques that can provide real time information. However these techniques generally lack spatial and chemical resolutions that are necessary to quantify the interfacial phenomena down to the atomic level. The objective of this project is to develop a unique method to image metal/water interfaces in three dimensions and at the nanoscale through unique cryo-preparation and cryo-imaging capabilities at the University of California, Berkeley and at the University of Michigan, respectively. It involves the development of specimen preparation from samples of ice that are suitable for examination by atom probe tomography (APT); focused ion beam (FIB) milling is the specimen-preparation method of choice. The high pay-off of the proposed approach resides in the versatility of the method that will allow not only metal-water systems to be studied, but will also be applicable to interfaces between hard and soft materials. NON-TECHNICAL SUMMARY: This project will develop a novel technique for imaging frozen solid-liquid interfaces. First, miniature needles will be machined out of a frozen specimen. Secondly, the frozen needle will be analyzed atom by atom to form a 3D image of the local chemistry and atomic arrangement. The technique will be able to analyze solid-liquid interfaces important for many scientific and industrial technologies. For instance, this technique can address corrosion phenomena important for alloy development that are currently understood only at a phenomenological level because of the lack of high resolution characterization techniques such as the one proposed here. The methods are expected to impact a large number of research areas relevant to the development of energy materials (such as structural materials for power plants, battery materials, nanoparticles for catalysis, and organic electronic devices). An integrated research and education plan will employ one or more undergraduate students to work with a post-doctoral researcher and leverage existing University programs that emphasize the recruitment of women and under-represented minorities.