The Preparation And Study Of Alumina Foam Ceramic

Foam ceramic is a new kind of porous ceramic materials with high porosity (80%-90%), which has three-dimensional network skeleton structure and open porosities. Foam ceramic has many good properties such as stable chemical properties, high compressive strength, high temperature resistance, good thermal shock resistance, large specific surface area and so on. The alumina foam ceramic was prepared by impregnating a polyurethane sponge of6ppi with ceramic slurry. The performances of the foam ceramic were analyzed by measuring apparent porosity, volume density, and compressive strength.The process procedure, sintering additives and sintering systems were analyzed in detail. Besides, preparation of ceramic foam with bauxite was also researched.Experiments showed that the alumina ceramic foam with highly uniform porosities could be prepared by centrifugal method. Adding organic binder PVA had affects the coating amount on the sponge., and adequate amount of PVA was10%. And inorganic binder aluminum dihydrogen phosphate could maintain the original shape at sintering processes of emission of carbon. But too much aluminum dihydrogen phosphate had no effects on the compressive strength, and5%of aqueous slurry weight was appropriate.It was found that green body could be obtained first by using aluminum dihydrogen phosphate as the main binder of the slurry for the first time, and second by centrifugal method. The green body had a certain strength after the exclusion of carbon, and its compressive strength was0.0313MPa after sintering, apparent porosity was92%. The surface of the sample was very smooth without plugging holes.It was proved that adding CaO and rare earth oxides could promote the sintering. The compressive strength of foam ceramic reached0.1124MPa with CaO addition amount of2%, and it reached the largest when Re2O3was2%. The compressive strength of the samples obtained by sintering system2was the largest among the different sintering systems, reaching0.0712MPa.In addition, the experiment proved that foam ceramics with a certain strength and porosity could be prepared using bauxite as raw material. And sintering temperature was significantly lower, which was only1300℃.Its compressive strength reached0.1297MPa.