Thermal Barrier Coatings

Thermal Barrier Coatings (TBCs) are coatings that insulate a metal component (such as the gas turbine or engines of an aircraft) and allow it to operate under extremely high temperatures.

Thermal barrier coatings are multilayer coatings consisting of a metallic bondcoat and ceramic topcoat applied on the substrate of interest.  The ceramic topcoat provides thermal protection in the form of a low thermal conductivity, strain compliant, ceramic structure. The bondcoat yields increased adhesion by providing thermal expansion matching, as well as acts as an oxidation barrier forming a slow growing oxide such as aluminum oxide (the thermally grown oxide or TGO).

While thermal barrier coatings can be fabricated from a range of compositions, the ceramic topcoat must have a low thermal conductivity (<2 W/m/K) and a high coefficient of thermal expansion match to the substrate. The most common topcoat ceramic for thermal barrier coatings is 7 weight percent yttria stabilized zirconia (7YSZ). 7YSZ has a good combination of low thermal conductivity, phase stability, and erosion resistance. Common bondcoat materials include MCrAlY compositions and platinum group metal aluminides.

While the TBC bondcoat layer can be applied via chemical or physical deposition techniques, the ceramic topcoat is generally applied by either electron beam-physical vapor deposition (EB-PVD) or plasma spray. Both of these processes can generate strain compliant, low thermal conductivity, erosion resistant coatings whose microstructures can be tailored for the desired application.

TBCs offer a range of benefits that include:

• Increased engine power
• Reduction in fuel consumption
• Improved thermal conductivity
• Increased lifespan of parts
• Protection from extreme temperatures

When operating under extreme high temperature, the structural material of your most critical components is at risk for degradation. Thermal protection is needed to ensure both performance and durability. But we take it one step further. With our line of nearly 100 thermal barrier coatings, we can protect and even extend the operating life of your most critical components.  

When finding the best solution for you, we first choose the optimal process for your part’s geometry and material composition. We then select a coating material to meet your specifications. And if we don’t have the best solution for your operation, we’ll develop it—designing proper sample characteristics and tailoring coating microstructure and performance to meet your requirements.