Silicon carbide refractory ceramics are mainly divided into recrystallized silicon carbide RSiC, pressureless sintered silicon carbide SSiC, silicon nitride combined with silicon carbide NSiC, and reaction sintered silicon carbide SiSiC according to the refractory temperature from high to low.
Recrystallized silicon carbide RSiC: grouting molding process, silicon carbide content is above 99%, operating temperature is 1650-1700℃, density is 2.72, mainly used in the field of technical ceramics, conventional products are support plates, square beams, etc. Under normal circumstances, recrystallized silicon carbide materials can be selected when the operating temperature is above 1400℃. It can also be used for daily porcelain, sanitary ware, and electrical porcelain. The characteristics of recrystallized silicon carbide ceramics are high-temperature resistance and high thermal conductivity, but at the same time, it has porosity, so it is not suitable for sealing refractory working conditions. In addition to kiln furniture such as slabs, square beams, and columns, there are also various types of tubes, furnace tubes, protective tubes, burner sleeves, crucibles, and various special-shaped parts;
Pressureless sintered silicon carbide SSiC: It adopts pressureless sintering technology, mainly for small precision parts, and the cost of large parts is very high. For extremely precise tolerance requirements, you can choose pressureless sintering products, such as sealing rings, precision special-shaped parts, various precision tolerance pipes, crucibles, etc.;
Silicon nitride combined with silicon carbide NSiC: What we are talking about here is the grouting molding process, secondary sintering, silicon nitride content 20-30%, silicon carbide content 70-80%, use temperature 1450℃, apparent porosity less than 1%, density 2.8, nitrogen-carbon combined material characteristics are light and thin, corrosion-resistant, can be directly in contact with metal solution, no iron increase, no bending, weak conductivity, good sealing, etc. The main products are various types of pipes, such as thermocouple protection tubes, radiation tubes, electric heating sleeves, liquid risers, furnace tubes, etc., as well as crucibles/saggers, which are widely used in metallurgy and chemical industries. Of course, the supporting plates, square beams, columns, fish-shaped plates, etc. used in daily-use porcelain, sanitary ware, and other industries have many advantages such as lightness, long life, energy saving, and space-saving.
Reaction sintered silicon carbide SiSiC (RBSiC): Currently, the most common process is extrusion molding, which has low cost, silicon carbide content of 85%, and the operating temperature is usually within 1300℃. The density is 3.02. The products are mainly square beam kiln furniture structure frames, as well as portable kiln frames, slats, fish-shaped plates, etc., which are commonly used in daily-use porcelain, sanitary ware, electric porcelain, and other industries. In addition, due to its low porosity, wear resistance, and corrosion resistance, it is also commonly used in various fields of metallurgy, the chemical industry, refractory and high-temperature resistance. The finished products include crucibles, saggers, rollers, burners, radiation tubes, etc.;
The characteristics of silicon carbide refractory ceramic products are different, and the actual use and cost are also very different. Therefore, you need to understand your own needs before making an accurate choice.