The application research of SiC Refractory is deepening, and its demand is increasing year by year

The formula of coarse, medium and fine SiC shall be 5:1:4. Black SiC is generally used as raw material for manufacturing silicon carbide brick, and its chemical composition is as follows: SiC 98.0%, free C O.5%, fe0.2%, free SiO2 0.6%. Due to different combination methods, the process is different. The brief processes of different combination methods are:

(1) Silicon nitride bonded silicon carbide brick: the green body formed with coarse, medium and fine silicon carbide particles and fine silicon powder produces a kind of% 26alpha at 1370 ℃ in pure N2 gas- SiC as skeleton and% 26alpha; And% 26beta- Si3N4。 Silicon nitride bonded silicon carbide brick as matrix. There are still a small amount of residual silicon and sio2n2 in the matrix. The relative content of these components varies with different manufacturing plants.

(2) Combined silicon carbide brick: mix and shape SiC, silicon powder and carbon powder according to a certain ratio, and burn them in a reducing atmosphere of 1400 ℃. In most cases, it is fired with buried carbon. In the firing process, a kind of% 26alpha is produced- SiC as skeleton, with fine grain% 26beta- % 26beta with SiC as matrix- Si3N4 bonded SiC brick 26beta;- SiC is formed by the reaction of fine silicon powder and fine carbon powder in the firing process. This product also contains a small amount of residual silicon and carbon.

(3) Silicon oxynitride bonded silicon carbide brick: the proportion of fine silicon powder is less than that of silicon carbide.

Recrystallized raw material silicon carbide refractory is a kind of high-grade refractory with SiC as the main component, which is fired from industrial SiC. It has a series of excellent properties such as high strength at room temperature and high temperature, large thermal conductivity, small linear expansion coefficient, good thermal shock resistance, excellent high temperature wear resistance and strong chemical corrosion resistance. It has been widely used in iron and steel, nonferrous metals, chemistry, electric power, ceramics, aerospace and other industrial fields.

With the in-depth research on the application of SiC refractories and the improvement of production level, the demand for SiC refractories is increasing year by year and the application field is expanding.

SiC products can be classified according to SiC content, binder type and addition amount. The performance of materials largely depends on the bonding status between SiC particles in materials. Therefore, SiC products are usually classified according to the type of bonding phase. According to different binding phases, SiC products can be divided into the following types.

1. Oxide bonded SiC

Al2O3-SiO2 silicate is used as the binding phase, including clay binding, mullite binding and SiO2 binding SiC.

2. Nitride bonded SiC

The binding phase is covalent compounds such as Si3N4, Si2N2O and Sialon.

3. Self bonded SiC

Including b-sic, bonded SiC and recrystallized SiC.

4. Siliconizing Reaction Sintering SiC

A SiC engineering ceramic material composed of SiC and free Si.

In addition, generally, refractory products with SiC content less than 50% are called semi SiC products. Semi SiC products include clinker SiC products, high aluminum SiC products, zircon SiC products, mullite SiC products and corundum SiC products.