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

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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.