Nanoscale Interdisciplinary Research Teams (NIRT): Superhard Nanostructured Films

这个纳米级跨学科研究团队(NIRT)将由一个团队进行，该团队包括断裂微观力学、结构和界面表征、等离子体技术、气溶胶技术和微制造方面的研究人员，以及洛斯阿拉莫斯和桑迪亚国家实验室的合作者。大量研究的证据表明，应该有可能生产出超硬的纳米晶复合材料，具有与钻石相当的硬度，并且还具有其他性能，使其在需要摩擦和耐磨的应用中优于钻石。提出了一种基于等离子体合成和沉积纳米颗粒的合成此类材料的新方法。合成工具将是高超声速等离子体粒子沉积，其中纳米粒子在热等离子体中成核，然后在高超声速膨胀中加速，使它们通过高速碰撞沉积。纳米复合薄膜将被沉积，其颗粒尺寸在5到10 nm之间，由硼、碳、氮、硅和钛的各种元素组合组成。在单独的实验中，空气动力学透镜将被用来将纳米粒子聚焦到准直光束。这些光束将与微加工技术一起用于演示由纳米颗粒制造微电子机械系统(MEMS)器件。这些合成研究将得到结构-性质关系的基础研究的支持。合成材料的结构、结晶度、化学成分和变形行为将在从原子水平到单个纳米颗粒、界面区域到整个薄膜的长度尺度上进行表征。除了这些实验研究外，还将在加工和后续机械性能的背景下对纳米颗粒在原子尺度上的变形进行数值模拟。来自洛斯阿拉莫斯和桑迪亚国家实验室的两个学术部门、几个实验室和合作者之间高度跨学科、高度互动的环境将为研究生和本科生提供广泛的纳米制造和纳米材料表征方面的经验。此外，参与NSF支持的Science Works计划的K-8学生将有机会体验这一新颖的研究领域。

This Nanoscale Interdisciplinary Research Team (NIRT) project will be conducted by a team that includes researchers on fracture micromechanics, characterization of structure and interfaces, plasma technology, aerosol technology, and microfabrication, together with collaborators at Los Alamos and Sandia National Laboratories. Evidence from a number of studies suggests that it should be possible to produce nano-crystalline composites that are superhard possessing hardness rivaling diamond and that also possess other properties that make them superior to diamond for applications requiring friction and wear resistance. A novel approach is proposed for synthesizing such materials, based on plasma synthesis and deposition of nanoparticles. The synthesis tool will be hypersonic plasma particle deposition, in which nanoparticles nucleate in thermal plasma and are then accelerated, in a hypersonic expansion, causing them to deposit by high-velocity impact. Nanocomposite films will be deposited with grain sizes in the range 5 to 10 nm, comprised of various combinations of the elements boron, carbon, nitrogen, silicon and titanium. In separate experiments, aerodynamic lenses will be used to focus the nanoparticles to collimated beams. These beams will be used in conjunction with microfabrication techniques to demonstrate fabrication of Micro-Electro-Mechanical System (MEMS) devices from nanoparticles.These synthesis studies will be supported by fundamental studies of structure-property relations. The structure, crystallinity, chemical composition and deformation behavior of the synthesized material will be characterized at length scales ranging from the atomic level to individual nanosized grains, to interfacial regions, to the entire film. In addition to these experimental studies, numerical simulations of nanoparticle deformation at the atomistic scale will be performed in the context of both the processing and the subsequent mechanical performance. The highly interdisciplinary, highly interactive environment between two academic departments, several laboratories, and collaborators from Los Alamos and Sandia National Labs will provide graduate and undergraduate students with a breadth of experience in nanomanufacturing and nano-materials characterization. In additions, K-8 students involved in the NSF-supported ScienceWorks Program will be provided the opportunity to experience this novel research area.