金套筒内SiO2气凝胶原位成型技术研究

低密度SiO₂气凝胶作为热波增殖和激光-K壳层X光转换实验中高效产生等离子体的媒质而受到广泛关注。本工作采用酸碱二步催化溶胶 凝胶法及CO₂超临界流体干燥工艺直接在内径为800μm、长为1200μm的金套筒内原位制备密度低至约10mg/cm³、成型较好的SiO₂气凝胶。采用X射线相称成像仪、光学显微镜、扫描电子显微镜等对金套筒内气凝胶的微观形貌以及金套筒与气凝胶的复合状况进行了表征，结果表明：气凝胶/金套筒界面处接触良好，界面附近与内部气凝胶密度存在差异。此外，着重讨论了金套筒的表面特性对气凝胶原位成型的影响，并对原位成型气凝胶结构差异的形成机理进行了探索。

In-situ Forming of SiO2 Aerogel in Gold Hohlraum

Low-density SiO2 aerogel as the medium for thermal wave increase and high-efficiency laser-X ray(K shell) conversion attracts more and more attention.Two-step(acid-base) sol-gel process and CO2 supercritical fluid drying technique were used to prepare SiO2 aerogel with the density of about 10 mg/cm3 in gold hohlraum with the internal diameter of 800 μm and the length of 1 200 μm by in-situ forming technique.X-ray phase contrast imaging,optical microscope,and SEM were used to characterize the microstructure of aerogel in gold hohlraum and interfacial structure between aerogel and gold hohlraum.The results show that aerogel/gold hohlraum interface is closely combined and the density of aerogel near interface is lower than that of the interior.Furthermore,effects of interface characteristic on in-situ forming of aerogel,and the formation mechanism of structure differences about in-situ forming aerogel were discussed.