Description of Silicon Carbide Brick:
Silicon carbide bricks are advanced refractory materials made of SiC as the main raw material, with a series of excellent properties such as high strength at normal temperature and high temperature, large thermal conductivity, small thermal expansion coefficient, good thermal shock resistance, excellent high temperature wear resistance, and strong resistance to chemical erosion, etc. Widely used in steel industry, non-ferrous metallurgy, petrochemical industry, electric power, ceramics and aerospace fields.
Silicon carbide bricks can be divided into oxide bonded (clay bonded, mullite bonded, SiO2 bonded), nitride bonded (Si3N4 bonded, Sialon bonded), self bonded (β-SiC bonded and recrystallized silicon carbide) and silicon infiltration reaction sintered silicon carbide bricks according to the bonding method.
1.Oxide Bonded Silicon Carbide Brick
(1)Clay Bonded Silicon Carbide Brick
Clay-bonded silicon carbide bricks are refractory products made of silicon carbide as the main raw material and fired with clay as the binding agent. Its characteristics are high thermal conductivity, low coefficient of thermal expansion, good thermal shock resistance and wear resistance.
(2)Mullite Bonded Silicon Carbide Bricks
Mullite bonded silicon carbide brick made of high purity raw materials, with industrial silicon carbide as the main raw material through in situ generation and crystalline transformation of mullite phase to play a binding role. Compared to clay bonded silicon carbide brick, the performance is better.
(3)SiO2 Bonded Silicon Carbide Brick
SiO2 bonded silicon carbide bricks are produced by adding a certain amount of quartz powder, which enhances the oxidation resistance by binding silicon carbide particles together with the help of silica film generated. The high temperature performance is better than clay bonded silicon carbide brick, and the high temperature strength is higher compared to mullite bonded silicon carbide brick.
2.Nitride Bonded Silicon Carbide Bricks
(1) Si3N4 Bonded Silicon Carbide Brick
Si3N4 bonded silicon carbide brick is an advanced refractory material with silicon carbide as the main raw material and Si3N4 as the bonding phase. It adheres to many excellent properties of nitride and SiC and has various excellent features such as high strength at high temperature, large thermal conductivity, small linear expansion coefficient, good resistance to thermal shock, good resistance to alkali erosion, good oxidation resistance, strong resistance to erosion of zinc, copper, aluminum and lead melt and good high temperature wear resistance, etc. Widely used in steel, non-ferrous metallurgy, ceramics and other industries.
(2)Sialon Bonded Silicon Carbide Brick
Sialon bonded silicon carbide brick and Si3N4 bonded silicon carbide brick are both nitride bonded silicon carbide brick, the performance is generally similar, due to the different bonding phase condition in the microstructure and performance there are some differences, the alkali erosion and water vapor oxidation resistance of sialon bonded silicon carbide brick is slightly better compared to Si3N4 bonded silicon carbide brick, while the thermal shock resistance is slightly inferior to the latter, according to the specific situation they can be reasonably selected.
3.Self-bonding Silicon Carbide Bricks
(1) β-SiC Bonding Silicon Carbide Brick
β- SiC bonded silicon carbide brick is produced the by the combining of the original SiC particles and β- SiC generated by in-situ reaction of metal silicon powder and carbon powder in raw materials at high temperature，the bonded phase has small grain size and high activity, the oxidation resistance and resistance to water vapor oxidation erosion and mechanical strength is slightly inferior to Si3N4 bonded silicon carbide brick, but other properties are close to both.
(2)Recrystallized Silicon Carbide Brick
Recrystallized silicon carbide brick, also known as R-SiC, is bonded by adding effective surfactant to α-SiC raw material and sintering at high temperature in protective atmosphere to make SiC evaporate and coalesce and recrystallize at the SiC particle bond. It has excellent properties such as high strength at high temperature, light weight, no slagging, good thermal conductivity, less heat storage, long life, etc. It is widely used in ceramics, petrochemical, aerospace and other fields, and is an excellent high temperature engineering material.
（4）Silicon infiltration reaction sintered silicon carbide brick (SiSiC brick)
SiSiC bricks are made by using reactive Si liquid or alloy to infiltrate into porous ceramics containing C through capillary force and react in situ to produce SiC to complete the densification process. SiSiC bricks have all the advantages of SiC ceramics, with high strength, high hardness, good thermal shock resistance, good wear resistance and corrosion resistance, high thermal conductivity, low coefficient of linear expansion, and excellent oxidation resistance, which is a High-tech ceramic material with excellent performance. Compared with R-SiC, it has excellent oxidation resistance, load-bearing capacity and volume stability.
