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Some advantages of silicon carbide ceramics

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silicon carbide ceramics has the following advantages over the widely used metal materials.
(1) High mechanical strength and good rigidity
High mechanical strength can effectively prevent deformation of the material, which is essential. The mechanical strength of silicon carbide is higher than that of corundum. For example, the compressive strength of silicon carbide 224MPa, corundum is only 75.7MPa; silicon carbide bending strength of 15.5MPa, while the corundum is 8.72MPa.
(2) Hardness, wear resistance
Silicon carbide hardness is quite high, according to the Mohs scale hardness of 9.2 ~ 9.6, second only to diamond and boron carbide, higher than the corundum and listed in the general grinding jittery front. Compared with the metal steel material, it is not only high hardness, but also in the non-lubricated state of friction coefficient is small, friction is relatively small, the surface roughness is small, has good wear resistance. In addition, it has a strong resistance to the impact of external substances, improving the surface’s ability to withstand.
(3)Low density
The density of silicon carbide ceramics is smaller than that of metal, and thus the equipment built is lighter.
(4)High temperature resistance and low coefficient of thermal expansion
Silicon carbide is made at high temperatures. In some high-temperature environments, the material is required to have a certain processing strength, but also to meet the processing accuracy, silicon carbide ceramics can achieve both. Silicon carbide has a maximum service temperature of about 800°C, while steel can withstand temperatures of only 250°C. Roughly calculated, the average coefficient of thermal expansion of silicon carbide in the range of 25 ~ 1400 ℃ is 4.4 × 10-6 / ℃. Measurement results of the coefficient of thermal expansion of silicon carbide shows that the amount of value compared with other abrasives and high temperature materials is much smaller, such as corundum’s coefficient of thermal expansion can be as high as (7 ~ 8) × 10-6 / ℃.
(5)High thermal conductivity
silicon carbide ceramics has a high thermal conductivity, which is another important feature of the physical properties of silicon carbide. The thermal conductivity of silicon carbide is much larger than that of other refractories and abrasives, and is about 4 times the thermal conductivity of corundum. Silicon carbide has a low coefficient of thermal expansion and high coefficient of thermal conductivity, so that its parts in the heating and cooling process is subject to less thermal stress, which is why silicon carbide parts are particularly resistant to heat shock reasons.
(6)Corrosion resistance
Because silicon carbide has a high melting point (decomposition temperature), chemical inertia and thermal shock resistance, so silicon carbide ceramics can be used for abrasives, ceramic products fired in the kiln with the shed and sagger, zinc refining industry, vertical cylinder distillation furnace with silicon carbide bricks, aluminum electrolysis tank lining, crucibles, small pieces of furnace materials, and many other silicon-carbide ceramic products.

silicon carbide ceramics