Study On The Preparing Technology Of Foam Ceramic

Foam ceramic with high porosity (70～90%) and a structure of open cells in a three—dimensional network is made by special technique.Foam ceramic have many good performance such as high intensity, enduring high temperature, good temperature resistant,large surface and so on . The open cell alumina foam ceramic were prepared by impregnating a polymeric sponge with aqueous ceramic slurry.The polymeric sponge impregnation process is an effective method to produce porous ceramic. This process has many potential advantages such as simplicity , easy contro1 and cheapness.The objective of this paper was to introduce this process in detail.This paper studies different kinds of factors that affect the performance of alumina foam ceramic.Foam ceramic were prepared by the polymeric sponge method. The polymeric sponge had bad wetting ability. After being treated by alkali, and modified by CMC and plasma surface modification, the roughness of the polymeric sponge surface roughness increases and the wetting ability between the polymeric sponge and the slurry increases. Both the increased surface and increased wetting ability lead to an increase of the loading of the slurry on the polymeric sponge.The polymeric sponge surface was modified by plasma in an original creation way. There was distinct change happened and good performance product was gotten.The favorable performance of slurry was required by impregnation a polyurethane sponge with ceramic slurry. The high solid content, equality and stabilization, excellent rheological slurry can be obtained by using proper adding. In the study, the best aqueous slurry can be obtained by adding 0.5% quality content PMAA-NH4.The intensity of green compact was important for the experiment. Silicon sol was chosen as binder though comparing .The best effect can be obtained by adding 0.5% quality content Silicon sol, the green compact had high intensity and sinking was prevent in the process of sintering . The produce was affected by the process of sintering. The proper temperature rise system was made via TG-DTA of the polymeric sponge and the green compact. (The polymeric sponge was completely decomposed at about 450℃. )The physical chemistry transformation,phase composition and microstructure of the as-prepared foam ceramic support were systematically characterized via TG—DTA,XRD,SEM and so on.The results indicated thatα-Al2O3 was major phase and mullite phase was minor in the sintered ceramic bodies.Microstructure pores in the sintered bodies were interconnected in all three dimensions. The alumina foam ceramics performance was tested , the results were as follows : bend strength was 1.4MP, compressive strength was 2.5MP,acid fastness was 99.33, alkali fastness was 99.06, softening temperature was above 1300℃, thermal expansion coefficient was between 1.6×10-6/℃and 2.5×10-6/℃, bulk density was between 0.28 g/cm3 and 0.48g/cm3 . The alumina foam ceramic with a very uniform macrostructure and few flaws were produced. The alumina foam ceramic had good performance.