The future of maintaining a superior mobile military ground vehicle fleet rests in high power density propulsion systems. As the U.S. Government desires to convert its powerplant base to heavy fuel operation, there arises the opportunity to incorporate new advanced materials into these heavy fuel engines. These newer materials serve the purpose of decreasing powerplant weight and develop new component designs to take advantage of improved strength and temperature capability of those materials. In addition, the military continues the effort for a non-watercooled Low Heat Rejection (LHR) diesel engine. This type of engine demands the use of ceramic and advanced ceramic composite material hardware. Furthermore, today's higher pressure fuel injection systems, coupled with reduced air/fuel ratio as a means of increasing horsepower to size and weight, will require thermal protection or change in material specification for many of the engine's components. The re-design or replacement of engine components will most likely require monolithic ceramic or composite engine hardware as a necessity. Although the ceramic or composite materials possess higher strength capabilities at predicted increased operating temperatures, they may not provide other desirable properties such as low thermal conductivity or good friction and wear. Recent work focuses on the application of Thermal Barrier Coatings (TBCs) to monolithic ceramics in an effort to reduce heat transfer through the ceramic monolith.