Abstract: Alumina foams were prepared by a polymeric sponge impregnation process. The effect of the parameters on the structures and properties of the foam ceramics was investigated. The coating formation on the foam ceramics by a sol–gel method was also in-vestigated. It is shown that three kinds of foam ceramics with different ppi (template pore per inch) values are obtained by pre-treatment to the polymeric with a NaOH solution of 15%, activation with a PVA solution of 5% and then coated by a centrifuging process. The pore size of the foam ceramics was in the range of 0.8–1.2 mm, and the vein size was 0.10–0.25 mm. The compressive strength of the foam ceramics, which increased with the increase of the ppi values, could be improved by slurry recoated by the cen-trifuging process. The thermal shock resistance increased with the decrease of the ppi values. The surface of foam ceramics could be well coated with a TiO2 gel coating by means of a negative pressure-impregnation process。
Key words: foam ceramics; alumina; sol–gel; coating
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