Ceramics for Gas Turbine Applications (A State-of-the-Art Survey),

Silicon nitride and silicon carbide are shown to be the ceramics having the most promise, with major efforts currently under way to develop these materials for use in the near future. Mechanical properties and data on oxidation and hot corrosion have been compiled and presented for comparison with those of currently available superalloys. These comparisons show hot-pressed ceramics to have strength and environmental resistance superior to nickel- and cobalt-base superalloys at elevated temperatures but lacking in impact strength. Reaction-sintered silicon nitride is shown to be a low-strength material. Hot-pressed silicon nitride and silicon carbide are expected to find application in situations where strength and reliability rather than cost are determining factors, whereas reaction-sintered silicon nitride offers distinct advantages when low cost achieved through mass production is of great importance for lower stress applications. Modified author abstract