To achieve greater engine fuel efficiencies, engines are running
at higher temperatures and must be cooled with more intricate
cooling schemes, requiring the casting of complex cooling
passages. Stronger metal alloys are being used in the casting
process, and the core material must be able to withstand the
extremely high temperatures used to pour these alloys. As an
example, consider the gas turbine, the efficiency of which is
largely determined by turbine temperature since the less cooling
air used, the more air is available for propulsion. Increasing
temperature capability of the turbine is therefore key to
improving such engines. Since engines run hotter as processing
temperature is increased, there is a need for demanding
materials to put together the engines. Seeking ways to lower
cost and emissions while increasing fuel economy and
performance, engine designers have been turning to advanced
ceramics and high-temperature metal materials. The ability of
these materials to withstand heat is key to making e