Limits of Tunability in Dealloyed Nanoporous Metals

技术概述：脱合金纳米多孔金属是通过选择性电化学溶解均匀固溶体合金的一个组分而制成的，在这种条件下，剩余的合金组分可能沿着金属/电解质界面扩散，重新形成具有纳米级孔和韧带大小的高多孔金属。这些新材料在（电）催化、光学传感和驱动方面的应用正在兴起，对其不同寻常的机械和电子性能的积极研究正在积极进行。尽管这些动力学过程控制着纳米多孔金属的最终形状、韧带晶体表面取向以及最终纳米多孔金属的表面和体积组成，但在纳米多孔金属的图案形成不稳定过程中，控制其形态和成分演变的动力学过程却研究得较少。该计划将详细研究控制纳米多孔金属形态演变的基本动力学过程，控制其表面成分，影响其加工/结构关系，并可用于制造新材料。总体目标是探索纳米多孔金属的形态和组成特征可以控制到什么程度。非技术总结：纳米结构材料研究的一个挑战是制造出大量的材料，这些材料在近原子尺度上具有可控的结构，并且仍然具有与纳米尺寸相关的不寻常和显著的特性。这种纳米技术规模化的成功可能转化为许多学科，并有助于改进从能源到传感到机械系统的一系列技术。该项目将深入研究一类大块纳米结构材料，即所谓的纳米多孔金属，这种材料是通过电化学溶解多组分合金中的一种或多种元素制成的。这些非凡的材料有一个连续的孔网，直径只有几十个原子宽；人们正在积极探索从催化到太阳能的各种应用。了解纳米多孔金属如何形成及其微观形状如何改变的基本物理和化学原理，将有助于了解这些材料的性质在多大程度上可以被控制，并开辟新的方法，将纳米尺度的性质转化为宏观尺度的世界。在此过程中，将开发和传播教学产品，包括探索传统冶金与可用于探测纳米材料结构演变的计算机模拟代码之间联系的介绍性讲座课程。

TECHNICAL SUMMARY: Dealloyed nanoporous metals are made by the selective electrochemical dissolution of one component of a uniform solid solution alloy under conditions where the remaining alloy components may diffuse along the metal/electrolyte interface to re-form into a highly porous metal with pore and ligament sizes on the nanoscale. Applications for these new materials are emerging in (electro)catalysis, optical sensing, and actuation, and active research into their unusual mechanical and electronic properties are being actively investigated. Less well-studied are the kinetic processes that control the morphological and compositional evolution of nanoporous metals during the pattern forming instability of their creation, even though these kinetic processes control the ultimate shape, ligament crystal surface orientation, and the surface and bulk compositions of the final nanoporous metal. This program will make a detailed study of the fundamental kinetic processes that control the morphological evolution of nanoporous metals, that control their surface composition, that influence their processing/structure relationships, and that can be used to make new materials. The overall goal is to probe how far the morphological and compositional characteristics of nanoporous metals can be controlled.NON-TECHNICAL SUMMARY: A challenge in the study of nanostructured materials is to make tangible quantities of materials that possess controlled structure at the near-atomic scale, and still possess the unusual and remarkable properties associated with nanometer size. Success at this kind of nanotechnology scale-up may translate to many disciplines, and help improve a range of technologies from energy to sensing to mechanical systems. This program will make an in-depth study of one class of bulk nanostructured materials, so-called nanoporous metals made by electrochemical dissolution of one or more elements from a multi-component alloy. These remarkable materials possess a contiguous network of pores whose diameters are only tens of atoms wide; they are being actively explored for a diverse range of applications from catalysis to solar energy. Understanding the fundamental physics and chemistry of how nanoporous metals form and how their microscopic shape can be changed will inform to what degree the properties of these materials can be controlled, and open up new methodologies to translate the properties of the nanoscale to the macroscale world. Along the way, pedagogical products will be developed and disseminated, including an introductory lecture course to explore the linkages between traditional metallurgy and a computer simulation code that can be used to probe nanomaterials structure evolution.