Sintering and Application of Silicon Carbide Ceramic Materials

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Silicon carbide ceramic materials have the advantages of wear resistance, corrosion resistance, high hardness, low density and high high temperature strength. Therefore, in recent years, they have been rapidly popularized in various fields and developed very rapidly. In aerospace, nuclear industry, petroleum industry, chemical industry, light textile industry, food industry and other special environments that require high temperature, high speed, corrosion resistance, vacuum, electrical insulation, non-magnetic, dry friction and other special environments, this new type of ceramic material has no Comparable substitution effects are gradually being recognized.

In addition to the above advantages, in the atmospheric pressure sintered silicon carbide ceramic material, the content of free silicon and free carbon is extremely small. For example, in the fine chemical industry, high cleanliness is required during the transportation of ultra-pure fluids. Atmospheric sintered silicon carbide ceramic materials can provide a very reliable transportation environment and protect the transportation environment. As people’s awareness of environmental protection increases, Atmospheric sintered silicon carbide ceramic materials will eventually replace reaction sintered silicon carbide products in the chemical industry.

At present, atmospheric sintered silicon carbide ceramic materials are mainly used in the following areas:

1. Sealed magnetic drive pump bearing assembly

With the rapid development of fine chemical products, especially the further implementation of the international standard ISO14000 in the fine chemical industry, it is necessary to prevent running, spilling, dripping and leakage, and to protect the environmental protection of the chemical industry, especially the transportation of corrosive liquids. High requirements and the pursuit of zero leakage have become the main goal of environmental protection in the chemical industry.

The sealed magnetic drive pump uses non-contact magnetic drive to generate torque and drives the pump shaft system components to work. Its main features: reduce a large space, and the overall volume of the pump is reduced by 20%-30%; it adopts non-contact transmission, The bearings and shafting components are all placed inside the pump body and fully enclosed, so that leakage-free work can be achieved. Under this working condition, the life of the bearing determines the overall life of the pump.

The normal pressure sintered silicon carbide ceramic material seal ring is used to replace the general mechanical seal, packing seal and other dynamic seals, so the leakage is smaller, the reliability is higher, and the service life is longer. The magnetic pump usually requires long-term maintenance-free, about 5-8 years, which puts forward extremely stringent requirements for the selection of magnetic pump shaft components. For example, the pump shaft, thrust plate, and shaft sleeve in the pump must be wear-resistant, corrosion-resistant, and zero leakage after assembly: At present, atmospheric pressure sintered silicon carbide ceramic has become the most suitable material of choice.

2. Mechanical seal ring

Atmospheric sintered silicon carbide ceramic has good chemical resistance, high strength, high hardness, good wear resistance, low friction coefficient, oxidation resistance, low temperature creep and good thermal stability, so it is an ideal material for manufacturing sealing rings. Due to the dense matrix of the material, free silicon and very little carbon content, it is increasingly widely used in high-purity, ultra-clean, fine chemical and other fields. The ultra-precision machining of the surface of the workpiece makes the friction coefficient smaller than that of alumina ceramics and cemented carbide when it is combined and matched, so it has a higher PV value, which is especially suitable for transporting strong acids, strong alkalis and corrosive liquids. use. Atmospheric pressure sintered silicon carbide ceramic products, with high density (310g/cm3-320g/cm3), high hardness (HPA95), and a variety of varieties, mass production of various complicated mechanical seal rings, such as flat rings, single-sided steps Ring, multi-step ring, etc.

3. Sandblasting nozzle

As a rising star to replace cemented carbide and alumina ceramic materials, atmospheric sintered silicon carbide ceramic materials have become second only to boron carbide ceramics and are the most used material in the sandblasting industry. Although the price of alumina ceramic nozzle is low, because of its low hardness and poor wear resistance, it is only used for occasions where the sandblasting workload is not large. In actual use, the service life of atmospheric sintered silicon carbide ceramics is 4-7 times that of alumina ceramics, and it is also an alternative product for high-density cemented carbide.

4. Bulletproof board

Since the British Chobham invented ceramic armor, atmospheric sintered silicon carbide ceramics are widely used in bullet-proof armor due to their high hardness, small specific gravity, better ballistic performance, and can absorb more energy after fragmentation, and are low in price. In the protection of vehicles and ships, as well as the protection of civilian safes and cash transport vehicles. The ballistic performance of atmospheric sintered silicon carbide ceramics is better than that of alumina ceramics, and the overall strength is about 70-80% of that of boron carbide ceramics. However, due to its low price, it is especially suitable for large quantities, and the protective armor should not be too thick or heavy. Occasions. Atmospheric sintered silicon carbide ceramic has the characteristics of high strength and good toughness. As a bulletproof armor material, its resistance to multiple blows is very good, so the overall protection effect is better than ordinary silicon carbide ceramics. It is used for cylindrical ceramic bodies. In the protective armor, the breaking point can reach more than 65 tons, and the protective effect is obviously better than that of the protective armor using ordinary silicon carbide ceramic cylindrical ceramic body.

Shanghai Geheng Vacuum Technology Co., Ltd. is a vacuum heat treatment furnace manufacturer with many years of experience in design, manufacturing and production. Mainly produce vacuum heat treatment furnace, vacuum sintering furnace, vacuum brazing furnace, New Energy And Environmental Protection Equipment and Vacuum Carbonization Furnace .Provide customized services, equipment work area can be based on customer output.