有机-无机转化法制备陶瓷基纳米复合材料

Ceramic matrix nanocomposites exhibted excellent proeprties and were considered as one of the most promising materials for widespread applications in energy, space and defense related areas. However, developments and applications of such materials have been drastically limited by the lack of suitable porcessing technology. Currently,the materials are primarily synthesized by using traditional metallurgy based processing technology. This technology has inherent drawbacks, such as the use of nano-scaled particles which are difficult to make in consistent way and contain undesired contiminations. In addition, the technique also leads to nonuniform distribution of the particles, limited volume fraction and dificult to consolidation. In this project, we propose to develop a new synthesis technology: polymer-derived ceramic based organic-inorganic conversion process. This new process contains following basic steps: synthesize block copolymer, assemble core-shell micelle, condense micelle into green body, and pyrolyze the green body to ceramic nanocomposites. We will systematically study the physical/chemical reactions within each step and their effects on the structureof the resultant nanocomposites. We will also study the strengtening and toughening mechanisms of the nanocompoistes. These studies will lead to processing-structure-property relationships for the new nanocomposites. Such relationships will form scientific guidelines for further design, synthesis and applicaions of the materials. Consequently, the proposed research will significantly advance our technology and fundamental science in the field of ceramic nanocomposites and promot the applications of the materials in key engineering areas.

陶瓷基纳米复合材料具有优异的性能，银次在能源、航空和国防等领域具有广泛的应用前景。然而，现有的基于传统粉末冶金工艺的制备技术有很大的局限性（例如，颗粒分散性差，增强相体积分数低等），并已成为限制这类材料广泛应用的主要障碍。针对这些工艺问题，本项目拟研究发展一种全新的合成陶瓷基纳米复合材料的工艺技术：基于聚合物前驱体陶瓷技术的有机-无机转化法。该方法的主要步骤为：合成嵌段共聚物、自组共聚物形成核-壳结构的胶束体、形成胶束体预制体和高温裂解转化。由此制备出的陶瓷基纳米复合材料将具有结构可控性、均匀性和良好的增强相分散性。本项目的研究将集中于理解工中艺每一步的物理、化学过程，及其对所得复合材料结构的影响；理解纳米复合材料的增强、增韧机理。从而获得工艺-结构-性能三者关系，为此类材料的设计和应用提供科学指导。本项目的研究结果将拓宽陶瓷基纳米复合材料在核心工程领域的应用，并促进纳米材料的基础研究。

本项目针对传统冶金工艺里粉末制备技术的局限性（例如，颗粒分散性差，增强相体积分数低等），研究发展一种全新的合成陶瓷基纳米复合材料的工艺技术：聚合物前驱体的有机-无机转化陶瓷法。研究将注重理解工艺中每一步的物理、化学过程，及其对所得复合材料结构的影响。从而获得工艺-结构两者关系。本项目的研究结果将拓宽陶瓷基纳米复合材料在核心工程领域的应用，并促进纳米材料的基础研究。