纳米陶瓷复合材料的自组装制备工艺和性能研究

Due to their unique/superior properties and potential applications in energy, space and defense related areas, ceramic matrix nanocomposites (CMNC) have attracted extensive attentions. Traditionally, CMNC was synthesized by sintering the mixture of matric-phase and reinforcing-phase particles. However, it is very difficult to achieve uniform distribution and a high volume fraction of the reinforcing particles by using this technique. Thereby, synthesis of ceramic matrix nanocomposites still represents a huge technical challenge. In this project, we propose a novel technology for synthesizing CMNC by using recently developed polymer-derived ceramic processing. The technique includes following basic steps: (i) uniformly mixing the matrix-phase and reinforcing-phase precursors; (ii) cross-linking the reinforcing-phase precursor to form nano-sized precipitation; (iii) cross-linking the matrix-phase precursor to form a solid precursor consisting of solid matrix-phase precursor and dispersed particles of reinforcing-phase precursor; (iv) pyrolyzing the solid precursor to form ceramic powder with nanocomposite structures; and (v) sintering the powder to obtain bulk ceramic matrix nanocomposites. The therodynamic/kinetic issues involved in each step will be investigated to obtain the fundamental understanding of the processing. The microstructures and properties of the resultant ceramics will also be characterized. Based on these studies, the relationships between the processing, structures and proeprties of the ceramic matrix nanocomposites will be built, which will be served as a scientific guideline for further design and applications of the materials. It is anticepted that the proposed technology will overcome the problems associated with the tridational technique and will enable the synthesis of ceramic matrix nanocomposites with uniform distribution and a high volume fraction of reinforcing particles; in addition, both size and volume fraction of the reinforcing particles can be tailored and well controlled by changing the precursor ratio and processing conditions. Therefore, the successful delivery of the proposed research will significantly advance the processing techonlogy, broaden the applications, as well as enhance the fundamental understanding of ceramic matrix nanocomposites.

陶瓷基纳米复合材料具备优异的性能，在能源、航空航天和国防等领域具有广阔应用前景，广受关注。这类材料通常由烧结基体和增强相粉体混合物制得；然而传统工艺很难得到均匀分散、大体积比增强相的复合材料。对此，本项目提出利用聚合物前驱体陶瓷技术制备陶瓷基纳米复合材料,具体工艺包括均匀混合基体相和增强相前驱体、交联增强相前驱体使其析出形成纳米颗粒、交联基体相前驱体、热解前驱体得到陶瓷粉体、烧结陶瓷粉体制得块体陶瓷基纳米复合材料。其创新处在于增强相颗粒是由前驱体相分离产生，分散性好且不受体积比限制；尺寸、体积比均可通过调整前驱体比例和处理条件控制。本项目将对制备过程中热力学和动力学问题展开研究，同时研究所得材料的结构和性能，以期得到材料的工艺-结构-性能关系，为今后材料设计和应用提供支持。因此，本项目的研究结果将推进陶瓷基纳米复合材料的制备技术发展，拓宽其在核心工程领域的应用，丰富纳米材料领域的理论基础。

陶瓷基纳米复合材料具备优异的性能，在能源、航空航天和国防等领域具有广阔应用前景，广受关注。针对传统工艺中陶瓷基纳米复合材料制备难的问题，本项目提出利用聚合物前驱体陶瓷技术制备陶瓷基纳米复合材料，得到均匀分散、大体积比增强相的复合材料。对此，本项目确定了相关材料体系的制备工艺路线，获得聚合物的相分离过程和热解过程变化规律，表征了材料体系的微观结构与性能特征，尤其是系统研究了材料的电学/介电性能和半导体性质。并从热力学和动力学角度展开深入研究分析，得到材料的工艺-结构-性能关系。本项目的研究结果将推进陶瓷基纳米复合材料的制备技术发展，为今后的材料设计和应用提供支持，拓宽其在核心工程领域的应用，丰富纳米材料领域的理论基础。