Oxidation and Strength of Silicon Nitride and Silicon Carbide
Ceramic components in a gas turbine have to operate in an oxidizing atmosphere at high temperatures. Nonoxides like Si3N4 and SiC, easily oxidizing materials, have to withstand this attack for long times without changing their characteristics.
The results of laboratory investigations on oxidation resistance and long time stability of Si3N4 and SiC are described. Recent materials show a satisfactory resistance against oxidation. Nevertheless, all materials investigated show changes in strength after annealing. Durability problems of ceramic components may arise from the strength degradation behaviour shown by nearly all materials at certain temperature levels.
KeywordsSilicon Carbide Silicon Nitride Oxidation Time Driving Cycle Strength Degradation
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