Sintering of compressed aerogels

Two different ways of densification of monolithic silica aerogels have been proposed in the literature. The first one corresponds to sintering, the second one to isostatic compression using a Hg porosimeter. In this paper, we analyse a combination of these two different methods. It is shown that a first isostatic compression followed by a further heat treatment reduces considerably the time required to achieve partial to almost full densification. This ‘two steps densification-process’ is analysed in the framework of a classical sintering model.