Antioxidant property
Silicon carbide thermocouple protection tube belongs to solid phase reaction sintering with little liquid phase. This microstructure gives the material high temperature strength. In addition to good wear resistance, the SiC itself in silicon nitride bonded silicon carbide refractory has high thermal conductivity and low thermal expansion coefficient, which makes nitride bonded silicon carbide tube have excellent thermal shock stability.
Chemical stability
The covalent bond strength of Si3N4 crystal structure is very large, has tetrahedral space network structure, good chemical stability, strong corrosion resistance, does not react with all inorganic acids (except HF), but can react with some bases or salts. It does not react to the melt of most metals, especially non-ferrous metals. At low temperatures, SiC is relatively stable, does not react with general strong acids, and has excellent corrosion resistance. If the SiC is mixed with impurities, such as Si, the reaction will occur at about 1400℃, resulting in a low eutectic, and a small amount of liquid phase will be generated, so that the high temperature performance of the material will be reduced. Because SiC does not melt at high temperature, it has significant advantages in resistance to high temperature chemical erosion.
Silicon carbide thermocouple protection tube combines the advantages of Si3N4 and SiC against chemical erosion, and its tightly interwoven form makes the surface of SiC particles well protected, hindering and delaying the penetration of external corrosive media, so that theNSIC heater protection tube has good chemical stability.
