SGER: Surface Reactivity of Nanostructured Light Weight Metals

SGER：纳米结构轻质金属的表面反应性

• 批准号: 0836068
• 负责人: Henry Rack
• 金额: $ 15万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-15 至 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0836068&HistoricalAwards=false
• 关键词: SGER; Surface; Reactivity; Nanostructured; Light

TECHNICAL: This SGER project will examine the role of substrate microstructure on the structure and electrical characteristics of native oxide films formed under ambient temperature conditions. This examination is intended to examine the hypothesis that observed differences in surface reactivity between the nanostructured, ultra-fine grained and normal coarse grained metals arise as a result of electrochemical differences, as evidenced by variations in local surface charge, these believed to arise from differences in amorphous oxide film thickness and structure between regions of native oxide films formed immediate above high angle grain boundaries and amorphous films which are formed above the substrate at distances removed from these boundaries. Furthermore as the grain boundary surface area per unit volume increases with nanostructuring, the differences between matrix and boundaries associated surface oxide surface and charge will become of increasing importance. The primary intellectual merit of these studies resides in the attention given to understanding the immediate region and interface lying between the native oxide film and the substrate, this being at length scales between 0.5 and 2 nm, and how this nanoscale structure is affected by the substrate microstructure, in particular by the presence of grain boundaries intersecting the metal substrate. EFM and HRSEM will be used, the former within a length scale below that previously attained. Finally the results obtained within this nanoscale region will be compared with those obtained at distances far removed from substrate defect. High Risk/High Payoff: The risk resides within the length scale capabilities of the techniques used for the examination. The EFM and HRTEM procedures required will be operating at and beyond the margin previously obtained - EFM being applied at 0.5-2 nm in the vicinity of the substrate grain boundary, while HRTEM will be examining the interface and atomic structure of amorphous films approximately 0.5-1 nm thick lying on a metallic substrate. While it is expected that these limits can be obtained, other approaches including field ion microscopy and scanning probe AFM are also under consideration. NON-TECHNICAL: Success of this high risk endeavor will provide a gateway to tailoring substrate structure and chemistry to define surface charge distribution. It can be envisioned that this knowledge will lead to enhanced osteointegration, utilization of nanostructured metals for cell growth scaffolds, self-healing mitigation of cell attachment, improved corrosion resistance, and catalytic response, all without recourse to surface treatment or coatings.

技术支持：该SGER项目将研究衬底微结构对环境温度条件下形成的自然氧化膜的结构和电特性的作用。该检验旨在检验这样的假设，即所观察到的纳米结构、超细晶粒和正常粗晶粒金属之间的表面反应性差异是由于电化学差异而产生的，如局部表面电荷的变化所证明的，这些被认为是由于在高角度晶界上直接形成的天然氧化物膜区域之间的非晶氧化物膜厚度和结构的差异引起的，非晶膜形成在衬底上远离这些边界的距离处。此外，随着每单位体积的晶界表面积随着纳米结构化而增加，与表面氧化物表面和电荷相关的基体和边界之间的差异将变得越来越重要。这些研究的主要智力价值在于关注理解自然氧化膜和衬底之间的直接区域和界面，这是在0.5和2 nm之间的长度尺度，以及这种纳米级结构如何受到衬底微观结构的影响，特别是通过存在与金属衬底相交的晶界。将使用EFM和HRSEM，前者的长度范围低于先前达到的长度范围。最后，将在此纳米级区域内获得的结果与在远离衬底缺陷的距离处获得的结果进行比较。高风险/高回报：风险存在于检查所用技术的长度范围内。所需的EFM和HRTEM程序将在先前获得的裕度处和超出该裕度进行操作- EFM被应用于衬底晶界附近的0.5-2 nm处，而HRTEM将检查位于金属衬底上的约0.5-1 nm厚的非晶膜的界面和原子结构。虽然预计可以获得这些限制，其他方法，包括场离子显微镜和扫描探针原子力显微镜也在考虑之中。非技术性：这一高风险奋进的成功将提供一个门户定制衬底结构和化学定义表面电荷分布。可以预见，这一知识将导致增强的骨整合，利用纳米结构金属的细胞生长支架，自我修复减轻细胞附着，改善耐腐蚀性，和催化反应，所有不求助于表面处理或涂层。