PIP工艺制备SiC/SiC复合材料导热性能研究

SiC/SiC composites are considered to be the promising candidate materials in aerospace and nuclear fields, because of its outstanding properties such as low density, high specific strength, high specific modulus, high temperature resistance, high thermal shock resistance, low radioactivity and high radiation resistance. The thermal cnductivity of existing SiC/SiC composites are low, especially for the SiC/SiC composites fabricated by PIP process. In this research, the key factors affecting the thermal conductivity of SiC/SiC composites are understanded by regarding the fiber, interphase and matrix. The thermal conductivity of SiC/SiC composites are simulated by using EMTA method and finite element software. Meanwhile, SiC/SiC composites with high thermal conductivity are fabricated by using home-made KD-ⅡSiC fiber as reinforcement, altering weaving of fabric perform, controlling the fiber/matrix interphase, using new liquid polymer and increasing pyrolysis temperature for improving the density and crystallinity of SiC matrix, which will meet the service requirements for aerospace and nuclear fields.

SiC/SiC复合材料具有低密度、高比强度、高比模量、耐高温、抗热震、低活化和耐辐照等优异性能，被认为是航空航天及核领域较理想的候选材料。现有SiC/SiC复合材料的导热性能偏低，特别是PIP工艺制备的SiC/SiC复合材料。本研究从SiC/SiC复合材料的纤维、界面和基体等三方面入手，理清影响SiC/SiC复合材料导热性能的关键因素，利用EMTA方法，通过有限元软件模拟计算SiC/SiC复合材料的导热性能；同时通过采用国产KD-Ⅱ型SiC纤维为增强体，改变SiC纤维编织方式，调控纤维/基体界面，利用新型液态先驱体和提高裂解温度优化PIP工艺，改善SiC基体的致密度和结晶度，最终期望制备出具有高导热率的SiC/SiC复合材料，满足航空航天及核领域的应用要求。

SiC/SiC复合材料具有低密度、高比强度、高比模量、耐高温、抗热震、低活化和耐辐照等优异性能，被认为是航空航天及核领域较理想的候选材料。现有SiC/SiC复合材料的导热性能偏低，特别是PIP工艺制备的SiC/SiC复合材料。本项目以提高PIP工艺制备SiC/SiC复合材料导热性能为目的，分别从SiC/SiC复合材料的纤维、界面和基体等三方面入手，通过利用国产KD-Ⅱ型和KD-S型SiC纤维为增强体，改进SiC纤维编织方式，调控纤维/基体界面，利用SiC微粉、新型液态先驱体和提高裂解温度等手段优化了PIP工艺，改善了SiC/SiC复合材料的致密度、结晶度和纯度，显著提高了PIP工艺制备SiC/SiC复合材料的导热性能，使其导热率提高了近4倍。本项目系统探讨了影响PIP工艺制备SiC/SiC复合材料导热性能的关键因素，理清了PIP-SiC/SiC复合材料的导热机理，初步建立了该复合材料的导热性能计算模拟方法，为进一步提高PIP-SiC/SiC复合材料的导热性能提供了科学指导。