Thermal Barrier Coatings (TBC)

One of the most common uses of Thermal barrier coatings TBC’s is in the combustion sections of aircraft turbine engines. With the demand for fuel economy and increased power, combustion temperatures are approaching the design limits of the metal alloys from which turbine components are made. The use of TBC’s in this and other applications enables the use of the alloys at higher temperatures, by reducing the temperature to which the parts are exposed. With the ability of thermal spray to apply an almost limitless number of materials, a well-engineered coating can be produced to solve even some of the most complex thermal barrier problems.

When engineering a TBC coating system, Thermal Spray Technologies uses its strong expertise in materials engineering and its strength of understanding of the processes of thermal spray. The combination of this knowledge provides application specific solutions to our customers’ thermal management problems.

Coating Materials

The most commonly used thermal spray TBC materials for turbine engines are oxide ceramics, specifically yttria-stabilized zirconia (YSZ). However, other materials can and have been used for thermal barriers, even metal alloys. Materials that have been used for thermal management include YSZ, alumina compounds, refractory metals, and stainless steels. Because every thermal management problem is unique, consultation with TST’s materials engineering staff is recommended.

Substrate Materials

There are few, if any, limitations to the substrate materials. Typically, TBC coatings are applied to metallic substrates, however, composite structures can also be coated. Where the application involves high temperatures, gradated coatings are employed to mitigate differential expansion between the substrate and the TBC coating.

Examples

Practical uses for TBC coatings include turbine blades, burner cans, and aft liners for turbine engines to increase fuel efficiency and power. TBC’s have been used in racing engines since the 70’s. Automotive and heavy equipment pistons and missile components are also coated with TBC’s. Thermal barrier coatings are also used in braking systems to keep heat away from hydraulic components.

Jet engines with various components coated with TBC’s