Dense ceramically bonded silicon carbide

Hardness testing of the refractories is not an everyday procedure, yet it is very useful to remember that the hardness of self-bonded silicon carbide ceramics is in the range of 20-25 GPa, the hardness of nitride-bonded silicon carbide refractories is 16-20 GPa, and the hardness of alumina ceramics is 12-16 GPa, which is three to four times higher than with dense alumina silica dense refractories. 

Properties of Dense Silicon Carbide. Properties of the SiC stmctural ceramics are shown in Table 1. These properties are for representative materials. Variations can exist within a given form depending on the manufacturer. Figure 2 shows the flexure strength of the SiC as a function of temperature. Sintered or sinter/HIP SiC is the preferred material for appHcations at temperatures over 1400°C and the Hquid-phase densified materials show best performance at low temperatures. The reaction-bonded form is utilized primarily for its ease of manufacture and not for superior mechanical properties. 

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