different kind silicon carbide ceramic

The preparation process of reaction bonded silicon carbide is relatively simple. this kind silicon carbide ceramic directly uses silicon carbide with a certain particle size distribution, forms embryos after mixing with carbon, and then carburizes under high temperature. Part of silicon reacts with carbon to generate SiC, which combines with the SIC in the original embryo to achieve the purpose of sintering. There are two carburizing methods: one is to reach the melting temperature of silicon, generate the melting temperature of silicon, and generate silicon vapor, The purpose of sintering is achieved by infiltration of silicon steam into the embryo. The production cost of SiC sintered body prepared by this process is low. However, this process determines the residual free silicon in the sintered embryo. This part of silicon should have an impact on the application of future products. On the one hand, it reduces the strength and wear resistance of the sintered body, and on the other hand, the existence of free silicon makes silicon carbide acid resistant.

Sintering free silicon carbide ceramics: pressureless sintering of silicon carbide can be divided into solid phase sintering and liquid phase sintering. The purity of pressureless sintered silicon carbide is high, the content of silicon carbide is more than 97%, the acid and alkali corrosion resistance is much better than that of reaction sintered silicon carbide, and it is easy to achieve batch production.

Hot pressing sintering silicon carbide ceramic is one of the most effective ways to prepare high density silicon carbide ceramic. The properties of hot pressed silicon carbide are generally higher than those of reaction sintered and pressureless sintered silicon carbide, especially its fine grains, high compactness, and high strength and hardness of products.

High temperature hot isostatic pressing sintering silicon carbide ceramics: High temperature hot isostatic pressing is an advanced ceramic sintering process. The ceramic powder or ceramic embryo is packed and put into a high temperature hot isostatic pressing device, and then sintered into a dense body under high temperature and high pressure. It is characterized by simultaneous and uniform pressurization, referred to as HIP.

Recrystallized silicon carbide ceramics: after mixing, shaping and drying, the raw materials are fired in an air insulated high temperature electric furnace at 2300~2500 ℃. When the temperature exceeds 2100 ℃, silicon carbide will evaporate and condense, resulting in the formation of recrystallized silicon carbide ceramics without sintering shrinkage and self binding structure.