Silicon nitride combined with silicon carbide bricks not only have the characteristics of high density, high strength, good thermal shock stability, high load softening point, good thermal conductivity, high resistance value, etc., but also have excellent resistance to melting erosion and oxidation resistance of cryolite, aluminum fluoride, sodium fluoride and calcium fluoride. It is mainly used in building sanitary ceramics, daily porcelain, electric porcelain, aluminum, copper, zinc smelting, steelmaking and rolling, ironmaking, metal heat treatment, environmental protection, and other fields.
Silicon Nitride Bonded Silicon Carbide Brick
Silicon nitride bonded silicon carbide brick is a kind of advanced refractory material with silicon carbide sand as the main raw material and silicon nitride as the bonding phase. Since SiC and Si3N4 are covalently bonded compounds, sintering is difficult, and reaction sintering is usually used in industrial production. SiC is used as aggregate, metallic silicon powder is added, and a reasonable particle grading, mixing system and forming process are selected. The dried green body is fired in a nitrogen atmosphere in a dedicated firing equipment. During the firing process, the generated Si3N4 (matrix bonding phase) is gray-white crystals. It can effectively combine SiC particles (aggregates) to form a spatial network structure, so that the brick has incomparable characteristics of other refractory materials. Silicon nitride bonded silicon carbide material is a special silicon carbide brick used in grinding wheels, ceramics, electric porcelain and other industries.
Superior Performance of Silicon Nitride Combined with Silicon Carbide Bricks
The high-temperature flexural strength of silicon nitride combined with silicon carbide is 4 to 8 times that of ordinary refractory materials. The thermal expansion coefficient is half of that of high-aluminum refractory materials. The thermal conductivity is 7 to 8 times that of general refractory materials, and the strength increases with the increase of temperature. When the temperature rises to 1400℃, the strength begins to decrease. But when the temperature drops to 1500℃, the room temperature flexural strength index is still maintained. The thermal conductivity of this material gradually decreases with the increase of temperature. It has the characteristics of high density, high strength, good thermal shock stability, high load softening point, good thermal conductivity, and high resistance value. And it has excellent resistance to melting erosion and oxidation resistance such as cryolite, aluminum fluoride, sodium fluoride and calcium fluoride. Its performance is as follows:
- 1) Silicon nitride combined with silicon carbide bricks are hard, with a Mohs hardness of about 9. It is a high-hardness material among non-metallic materials, and its hardness is second only to diamond.
- 2) Silicon nitride combined with silicon carbide bricks have high strength at room temperature, and maintain almost the same strength and hardness as at room temperature at high temperatures of 1200-1400℃. Depending on the use atmosphere, the maximum safe use temperature can reach 1650-1750℃.
- 3) The thermal expansion coefficient is small, and the thermal conductivity is high compared to silicon carbide bricks. It is not easy to produce thermal stress, has good thermal shock stability, and has a long service life. It has strong high-temperature creep resistance, corrosion resistance, extreme cold and heat resistance, oxidation resistance, and is easy to make bricks with high dimensional accuracy that meet the requirements.
Application of Silicon Nitride Combined with Silicon Carbide Bricks in the Ceramic Industry
Building Sanitary Ceramics Industry
At present, in the firing of ceramic products, roller kilns are mostly used to fire sanitary ceramics and wall and floor tiles, and the rollers of the roller kilns are basically made of silicon nitride combined with silicon carbide. The application of silicon nitride combined with silicon carbide rollers solves the problem of high firing temperature and heavy load, effectively reduces product energy consumption and improves product quality.
Daily Ceramics Industry
There are two ways to fire daily ceramics: one is to use a shuttle kiln with a sagger or similar kiln; the other is to use a roller kiln in the same way as building sanitary ceramics. The use of kiln tools made of silicon nitride combined with silicon carbide can significantly reduce the mass ratio of kiln tools to bricks, save energy and reduce consumption, and at the same time improve the quality and qualified rate of products. Using a roller kiln to fire daily ceramics, the use of silicon nitride combined with silicon carbide rollers increases the service life of the kiln.
Electrical Porcelain and Electronic Ceramics Industry
The electrical porcelain and electronic ceramics industry requires kiln furniture materials with high temperature, high strength, good thermal stability, long service life and reasonable price, which provides a broad market for the application of silicon nitride combined with silicon carbide kiln furniture.
Silicon nitride combined with silicon carbide has high density, high strength, good thermal shock stability, high load softening point, good thermal conductivity and high resistance. It also has excellent resistance to melting erosion and oxidation resistance of cryolite, aluminum fluoride, sodium fluoride, and calcium fluoride. It plays an increasingly irreplaceable role in building sanitary ceramics, daily ceramics, electrical porcelain, non-ferrous smelting, steelmaking and rolling, ironmaking, heat treatment, environmental protection and other industries. To buy high-quality silicon carbide bricks, please choose Rongsheng. Contact Rongsheng for free samples and quotes.
