123

The Higher Service Temperature, The Worse Wear Resistance Of Refractory Bricks.

Feb 19, 2024

Choose four types of refractory products: high alumina bricks, corundum bricks, silicon nitride bonded silicon carbide bricks and clay bonded silicon carbide bricks. As can be seen from Figure 1: three types of oxides: high alumina bricks, corundum bricks and clay bonded silicon carbide bricks ( The high-temperature wear amount curves of refractory materials (or oxide combination) have a common feature: within a certain temperature range, the wear amount does not change much; but when the temperature exceeds a certain value, the wear amount decreases significantly. The reason may be that as the temperature increases, the internal structure of the refractory product will undergo a transition from elasticity to plasticity: when the material is in the elastic temperature range, as the temperature increases, the material structure does not change, so the wear amount does not change. Large; when the material is in the plastic temperature range (for example, the plastic stage of high alumina bricks is 800-1200°C), a small amount of low-melting point minerals inside the material melt (or soften the glass phase) and deform, causing the material to become plastic. Under high-temperature conditions, this plasticity has a negative impact on the wear medium. The impact has a certain buffering effect. The plastic deformation of the material absorbs the impact kinetic energy of the wear medium and hinders the generation and expansion of cracks, so the amount of wear is significantly reduced. For high alumina bricks, as the test temperature increases, the degree of plastic deformation of the material increases and the decrease in material wear increases.

Although the internal structure of refractory products will change from elasticity to plasticity as the temperature increases, due to differences in materials or bonding phases, the temperature at which the material becomes plastic is different. Therefore, the corresponding temperature point at which the wear amount of the material begins to decrease significantly is also Are not the same. As can be seen from Figure 1, the temperature point at which the wear amount of corundum bricks begins to decrease is 1000°C, while that of high alumina bricks is 800°C. Because the impurity content of high alumina bricks is high, a liquid phase will be generated at a lower temperature, making the material in In the plastic state, the wear amount begins to decrease significantly. For the same reason, the temperature point at which the wear amount of clay-bonded silicon carbide bricks begins to decrease significantly is about 600°C. The high-temperature wear amount curve of the non-oxide material silicon nitride combined with silicon carbide brick has another characteristic. Its wear amount has almost no change in the entire test temperature range, and its wear amount-temperature curve is close to a horizontal straight line. The raw materials used for silicon nitride combined with silicon carbide materials are of high purity, and the final silicon nitride combines hard silicon carbide to form a dense network structure. Since both silicon nitride and silicon carbide are compounds with extremely strong covalent bonds, they still maintain high bonding ability at high temperatures. The material does not contain low melting point phases. Within the test temperature range, silicon nitride combines with silicon carbide. The brick is still in the elastic temperature range, so the amount of wear changes little with increasing temperature. Above 1 000 ℃, the wear amount of the brick decreases slightly, which is the result of the weight increase caused by the oxidation of the sample surface to form a silicon oxide film in the oxidizing atmosphere, which affects the calculation of the wear amount.

Contact us

Quick Reply
Contact us

Need Help? Chat with us

leave a message
If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.
Submit
Looking for Contact
Contact us #
+86 15370305859

Home

products

WhatsApp

contact