Substitution of ceramics for high temperature alloys

Ceramics such as silicon nitride and silicon carbide are currently receiving a great deal of attention as potential materials for advanced gas turbine engines. The primary advantage offered by ceramics is their high temperature capability which can result in turbine engines of improved efficiency. Other advantages when compared to the nickel and cobalt alloys in current use are raw material availability, lower weight, erosion/corrosion resistance, and potentially lower cost. The use of ceramics in three different sizes of gas turbine engines is considered; these are the large utility turbines, advanced aircraft turbines, and small automotive turbines. The effects of material substitutions are reviewed in terms of engine performance, operating economy, and secondary effects.