聚硅氧烷热解SiCf/Si-O-C吸波材料介电温频响应调控机理

项目名称： 聚硅氧烷热解SiCf/Si-O-C吸波材料介电温频响应调控机理

项目编号： No.51502236

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 无机非金属材料学科

项目作者： 丁冬海

作者单位： 西安建筑科技大学

项目金额： 21万元

中文摘要： 连续SiC纤维增强陶瓷基高温结构吸波材料集吸波、防热、承载与一体，其发展对新型装备雷达隐身意义重大，但基体自由碳含量/有序度及复合材料介电温频响应特性的有效调控机理仍是高温结构吸波材料亟需解决的关键问题。本申请创造性提出将自由碳含量、有序度及介电常数可调途径较多的聚硅氧烷热解Si-O-C陶瓷作为基体，制备SiCf/Si-O-C高温吸波材料，进行聚硅氧烷分子结构及热解、高温退火工艺条件对自由碳含量与有序度的影响规律研究，建立自由碳含量/有序度的有效控制方法，可避免目前采用化学气相渗透、聚碳硅烷浸渍裂解法制备的SiC基体自由碳含量及有序度过高导致复合材料复介电常数过高、与空气阻抗失配、对雷达波反射明显的问题。阐述自由碳含量、有序度与复合材料不同温度复介电常数频率响应特性的关系，获得SiCf/Si-O-C复合材料介电温频响应特性的调控方法，为高温结构吸波材料强吸收、宽频化设计提供理论基础。

中文关键词： 高温吸波材料；介电性能；自由碳；聚硅氧烷热解Si-O-C；陶瓷；频响特性

英文摘要： The continuous SiC ceramic reinforced ceramic matrix composite high temperature stuctural radar wave absorbing materials, which have intergrated functions of microwave absorbing, thermostability and load bearing, play a key role in novel radar stealth equipments. However, both the the effective control methods of content and order of free carbon in matrix and the regulating methods of dielectric teperature/frequence response of composites are the key issuse of high temperature stuctural radar wave absorbing materials. In our application, in view of its controllable content and order of free carbon and complex permittivity, the polysiloxane derived Si-O-C ceramics would be originally used as matrtix, and the SiCf/Si-O-C high temperature radar wave absorbing composites would be fabricated to avoid the problem of too high complex permittvity, impedance mismatching bewteen air and strong reflection of radar wave caused by too much free carbon in SiC marixs fabricated by both chemical vapor infiltration and polycarbosilane impreganation pyrosis. The control methods of content and order of free carbon in Si-O-C matrix would be found through investigating the effects of polysiloxane architecture, pyrolysis process, and annealing on the content and order of free carbon in Si-O-C matrix. The influencing mechanism of content/order of free carbon on dielectric teperature/frequence response characteristics of composites would be elaborated. Then, the regulating ways of dielectric teperature/frequence response characteristics of SiCf/SiOC composites would be known well. The implement of this project would provide new routes and theroretical guidances for the design of broadband and strong absorption of high temperature structural radar wave absorbing materials.

英文关键词： high temperature radar wave absorbing materials ;dielectric properties;free carbon;polysiloxane dericed Si-O-C ceramic;frequency response characteristic