Special Ceramic
Special ceramic usually has alumina,zirconia,silicon nitride silicon carbide and so on.
Advantages of Special ceramic:
Special ceramic have excellent mechanical properties at room temperature. These include high bending strength, excellent oxidation resistance, good corrosion resistance, high wear resistance, and low friction coefficient. Furthermore, high temperature mechanical properties (strength, creep resistance) are the best among known ceramic materials.
The high temperature strength of hot press sintering, pressureless sintering, and hot isostatic pressing sintering materials can maintain to 1600 °C.
Silicon carbide ceramic as one of the special ceramic,the disadvantage is fracture toughness is low. Therefore, in recent years, special silicon carbide ceramic based on the improved toughness and strength of monomer materials. Silicon carbide use in petroleum, chemical, microelectronics, automotive, aerospace, aviation, papermaking, laser, mining, and atomic energy industries.
Features of special silicon carbide ceramic:
1.Good stability
SiC and silicic acid do not react at high temperatures, so it has good properties against acid slag. SiC reacts with lime at 525 degrees. The reaction is significant around 1000 degrees. It reacts with iron oxide at 1000-1200 degrees, and has obvious cracking reaction at 1300 degrees. The reaction with manganese oxide is from 1360 degrees to the cracking reaction. SiC reacts with it in chlorine gas from 600 degrees and decomposes into SiCl4 and CCl4 at 1200 degrees. The molten alkali can decompose SiC under red-hot heat.
2.Good oxidation resistance
Silicon carbide has good oxidation resistance at room temperature. Moreover, the residual Si, C, and iron oxide during the synthesis of SiC have an effect on the oxidation degree of SiC.In comparison, silicon carbide, which contains some impurities, will oxidize at 1220 degrees.
3.Good thermal shock resistance
Since silicon carbide does not melt and decompose vapor at a high temperature, it has high thermal conductivity. Furthermore, with low thermal expansion, it has good thermal shock resistance.