论文部分内容阅读
针对气凝胶在航空航天领域的应用需求,为了进一步拓展单一密度气凝胶的应用范围,对密度梯度SiO2气凝胶的制备进行了研究。采用自建密度梯度制备成型装置,以正硅酸乙酯为有机硅源,经溶胶共凝工艺,结合CO2超临界干燥技术,获得密度范围在60～160mg/cm3的准连续密度梯度SiO2气凝胶。采用光学显微镜、扫描电子显微镜、X射线相衬成像等手段对制备获得的SiO2气凝胶进行测试表征。通过与逐层凝胶法制备的密度渐变SiO2气凝胶进行对比发现,溶胶共凝工艺消除了层间界面处所产生的致密层和密度突变,有利于相邻两层间的互扩散,使密度变化更趋于连续。采用该法制备的密度梯度气凝胶拓展了常规气凝胶的应用范围,在声阻抗匹配和空间粒子捕获等领域有潜在的应用前景。
In order to meet the application requirements of aerogels in the aerospace field, in order to further expand the application scope of a single density aerogels, the preparation of density gradient SiO2 aerogels was studied. A self-built density grading preparation and molding device was used. Ethyl orthosilicate was used as the organic silicon source, and the solute co-coagulation process and CO2 supercritical drying technology were used to obtain the quasi-continuous density gradient SiO2 airgel with the density range of 60 ~ 160mg / cm3 glue. The prepared SiO2 airgel was characterized by optical microscopy, scanning electron microscopy and X-ray phase contrast imaging. The comparison with density gradient SiO2 aerogels prepared by layer-by-layer gel method shows that the sol-gel process can eliminate the sudden change of density and density at the interlayer interface, which facilitates the mutual diffusion between two adjacent layers, Changes tend to be more continuous. The density-gradient airgel prepared by the method expands the application range of the conventional airgel, and has potential applications in the fields of acoustic impedance matching and space particle capture.