Silicon carbide (SiC) is an important inorganic non-metallic material, which is widely used in wear-resistant refractory castables. The following are its characteristics and its role in wear-resistant refractory castables:
I. Characteristics of silicon carbide
1• High hardness: The Mohs hardness of silicon carbide can reach 9.2-9.5, which is second only to a few materials such as diamond and cubic boron nitride. It has excellent wear resistance and can resist the erosion and friction of materials.
2• High melting point: The melting point is as high as about 2700℃. It can maintain good stability in high temperature environment, is not easy to melt or soften, and can withstand high temperature conditions in industrial production.
3• High thermal conductivity: The thermal conductivity is high, much higher than that of general refractory materials, and can quickly conduct heat, so that the temperature distribution of the castable is more uniform when heated, reducing thermal stress concentration.
4•Good chemical stability: At room temperature, silicon carbide does not react with most chemicals such as acids and alkalis, and has good corrosion resistance to many molten metals, slag, etc. at high temperatures.
5•Antioxidation: Within a certain temperature range, a dense silicon dioxide protective film will form on the surface of silicon carbide to prevent further oxidation and increase its service life in high-temperature oxidizing atmospheres.
2. Role in wear-resistant and refractory castables
1•Improving wear resistance: With its high hardness, silicon carbide can significantly enhance the wear resistance of castables, effectively reduce the wear rate of castables during use, and extend its service life. It is especially suitable for parts with severe wear, such as material conveying pipelines, chutes, etc.
2•Enhancing high temperature resistance: High melting point and good thermal stability enable castables to withstand higher temperatures, reduce deformation and damage at high temperatures, and can be used for linings, furnace tops, and other parts of high-temperature kilns.
3. Improve thermal shock stability: High thermal conductivity helps the castable to dissipate or absorb heat quickly and evenly when the temperature changes sharply, reduce thermal stress, improve its thermal shock resistance, and enable it to better adapt to frequent furnace opening and shutdown and other thermal shock conditions.
4. Improve corrosion resistance: Chemical stability and oxidation resistance can make the castable resist the corrosion of slag, high-temperature gas, etc., maintain structural integrity, and have significant application effects in industrial furnaces with strong corrosive media such as metallurgy and chemical industry.
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