| Foam ceramic was a new nonmental porous material , it has 70%~90% porosity and three dimension solid net framework structure. Silicon carbide was a strong covalent bond compound, which has favorable high temperature capability, electricity capability, mechanism capability and chemistry capability. Preparation foam ceramic by silicon carbide material can well band together the choiceness capability of silicon carbide ceramic and application of porous ceramic, it will has wider application foreground.The foam silicon carbide ceramics were prepared by impregnation a polyurethane sponge with ceramic slurry in these studies. The effect of different craftwork factor on properties of foam silicon carbide ceramics were studies. The properties and microstructure of foam ceramics were analyzed and discussed by XRD, SEM, EDS, press Hg methods.The optimited properties of slurry was required by impregnation a polyurethane sponge with ceramic slurry. The slurry for preparating foam silicon carbon ceramic include aqueous slurry and nonaqueous 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 0.08% quality content PAM; the best nonaqueous slurry can be obtained when the ratio was 1ml:1g for nonaqueous ethanol compare colophony. The aqueous slurry and nonaqueous slurry have the same properties, which can be induced to sloopy by shearing and depend on time. The suspension exhibits positive thixotropy.The important effect of sample properties for sinter craftwork were discovered in study. The porosity of products obtained by ordinary pressure sinter was accretion when the sinter temperature hoist. The height of strength was limited by sinter temperature and porosity. In 1480℃ sinter temperature, the compressive strength as high as 0.54 MPa. The electricity properties of products obtained by ordinary pressure sinter was badly and was belong to insulator.Reaction sinter was sinter without size change, the effect of sinter temperature for products porosity was not important. The porosity was effected by density of flan. The porosity was minished as density of flan accretion. The mechanical strength was effected by porosity, sinter temperature, content of infiltrating Si and time of reaction. The bending strength as high as 6.704Mpa. the well electricity properties of samples can be obtained by reaction sinter, having 0.05～0.5Ω·cm resistance ratio.The foam silicon carbide ceramics preparated by reaction sinter were well inherited network porous structure of sponge. The macrocells were 0.5~3mm, in millimeter level. The pore size distribution of microcells were presented parallel peak, part of them concentrate in 0.003~0.0351μm, and then concentrate in 16.4~34.3μm. The sample has high skeletal density (3.2965g/cm3) and pore area (17.1096m2/g), it will provide well base for application.The adding elements such as B,Fe, Al, have no useful action for electricity properties of foam ceramics by study on electricity properties was discovered. The content of carbon in flan was effected electricity properties of products. The smallest resistance ratio was 0.066Ω·cm when infiltrate Si to full carbon flan. The foam silicon carbide ceramic having penetrability, resist causticity, heatproof and aseismatic were obtained by this study, it can be heated by electrification. The foam ceramic can heat up liquid with high thermal efficiency.Porous silicon carbide ceramic have 25%~40% porosity can be obtained by pile up grain. Compare to impregnation a sponge with ceramic slurry, the products by this technique having high strength, low resistance ratio. It can chose different preparation technique by different require of products properties.
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