Collaborative/FRG Research: Nano-structured Materials of Covalently Bonded Networks

大量技术上有用的、不寻常的和令人兴奋的超硬和超强材料，如金刚石、碳纳米管和SiC，都是由碳通过C与其自身以及与其他元素如N、B和Si的共价键合而衍生的。存在一类重要的非晶、部分非晶和纳米晶体材料，例如具有不寻常性质的类金刚石碳和高度四面体非晶碳。结果表明，非晶相在非平衡加工条件下金刚石和氮化硼的形核和生长过程中起着重要作用。这个重点研究小组的主要目标是：（1）在三元（C-B-N）体系的聚焦区域中合成具有受控纳米结构和性能的不寻常的C基共价键合的非晶和纳米晶体材料，（2）开发/应用先进技术来表征这些材料的纳米结构，以及（3）将纳米结构的尺度和无定形网络的连接性与所选择的性质相关联。考虑到这一愿景，拟议的FRG的前提是，薄膜和涂层形式的纳米结构材料的功能/性能可以通过采用合适的纳米级结构和基本结构构建块的分布来设计，以控制性能。在这个由辛辛那提大学的研究人员和CO矿业学院的Kleebe教授组成的FRG中，纳米结构薄膜的设计将不仅仅是细化多晶微观结构尺度，而是探索合成、表征和控制新材料纳米结构的非晶路线，以实现不寻常的机械、物理、热和可能的其他性能。因此，材料将首先被设计和合成/生产，只有短程秩序，然后纳米结构的薄膜将通过非平衡处理方法的巧妙修改，和网络/纳米结构的动力学/热操纵，以创建纳米晶体薄膜。这些活动的最终目标是开发设计和合成具有特殊性能的材料的预测工具，以便获得"通过设计创造材料"的知识基础。在更广泛的范围内，这项研究的成功完成将为设计C-B-N三元纳米结构材料提供知识基础，这些材料具有不寻常的机械和物理性能，可用于机械加工，电子设备，MEMS和功能/保护涂层。特别是，将获得对纳米尺度结构，微观结构和界面材料在创造新材料中的作用的科学理解。研究生和本科生以及研究助理/博士后将通过参与本研究项目及其论文进行培训。将开发一门新的薄膜等离子体加工课程，并教授本科生和研究生。此外，少数民族/女高中生将通过辛辛那提大学的NASA-SHARP计划接受指导和接触这项研究。

A large number of the technologically useful, unusual, and exciting superhard and superstrong materials such as diamond, carbon nanotubes, and SiC are derived from carbon by covalent bonding of C to itself, and with other elements such as N, B, and Si. There are an important class of amorphous, partially amorphous, and nano-crystalline materials such as diamond like carbon and highly tetrahedral amorphous carbon with unusual properties. It has been shown that the amorphous phase plays an important role in the nucleation and growth of diamond and cubic-BN upon non-equilibrium processing. The primary objectives of this focussed research group will be to: (1) synthesize unusual C-based covalently-bonded amorphous and nano-crystalline materials with controlled nano-structures and properties in the focussed region of the ternary (C-B-N) system, (2) develop/apply advanced techniques to characterize the nano-structures of these materials, and (3) relate the scale of the nano-structure and connectivity of the amorphous network to the selected properties. With this vision in mind, the premise of the proposed FRG is that the functionality/property of nano-structured materials in the form of thin films and coatings can be designed by employing a suitable nanoscale architecture and distribution of the basic structural building blocks to control the properties. In this FRG comprised of researchers at the University of Cincinnati and Prof. Kleebe at the CO School of Mines, the design of nano-structured thin films will go beyond just refining the polycrystalline microstructural scale, to exploring the amorphous routes for synthesizing, characterizing, and controlling the nano-structure of new materials in order to achieve unusual mechanical, physical, thermal, and possibly other properties. Thus, materials will be first designed and synthesized/produced to have only short-range order and then nano-structured thin films will be created by clever modifications of the non-equilibrium processing methods, and kinetic/thermal manipulation of the networks/nanostructues to create nano-crystalline thin films. The eventual aim of these activities will be to develop predictive tools for designing and synthesizing materials with unusual properties so that a knowledge base for "creating materials by design" will be obtained. On a broader scale, a successful completion of this research will lead to a knowledge base for designing nano-structured materials in C-B-N ternary with unusual mechanical and physical properties for applications in machining, electronic devices, MEMS, and functional/protective coatings. In particular, the scientific understanding of the role of the nano-scale structure, microstructure, and interfacial materials in creating novel materials will be obtained. Graduate and undergraduate students and research associate/post doc will be trained through participation on this research project and their theses. A new course on Plasma Processing of Thin Films will be developed and taught to undergraduate and graduate students. In addition, minority/women high school students will be mentored and exposed to this research through NASA-SHARP program at University of Cincinnati.