| 摘要 |
A process for foaming ceramic foams, in which the ceramic foams are produced from a precursor or a mixture of precursors which contain at least one ceramic-forming element and liberates at least one volatile reaction product during an inorganic gelation process. In one embodiment, foaming is based on a precursor containing crystals of the AlCl3(Pri2O) complex. The decomposition of the initial precursor produces polymerizing species dissolved in liquid isopropyl chloride. The solvent and growing AlOxCly(OPri)z species are mixed homogeneously so that the boiling point of the solution is raised above the boiling point of the pure isopropyl chloride. Polymerization takes place in the liquid until a critical polymer size is attained, whereupon a phase separation into polymer rich and solvent rich regions occurs. Since the expelled solvent is suddenly above its boiling point, bubbles start forming instantly. Foam stabilization takes place as a result of gelation in the polymer rich regions which comprise cell walls in the foam. The net result of the process is a gelled ultra light foam.
|
