Hotter running engines

Researchers at the US Department of Energy’s Ames Laboratory and Iowa State University have developed a new bond coat for thermal barrier coatings, or TBCs, that may allow gas turbine engines in aircraft and other power-generating technologies to better withstand severe, high-temperature environments.

The basic research effort could provide a TBC system with significantly improved reliability and durability of turbine blades, thus enabling higher operating efficiencies and extending engine lifetimes.

Commercial thermal barrier coatings consist of three layers. The first layer is typically an aluminium-rich bond coat that is based on the compound nickel-aluminium, or NiAl. The bond coat is applied directly to the turbine blade. The second layer is a thin, thermally grown oxide, or TGO, which forms as the aluminium in the bond coat oxidizes. The third layer, a thin (around half a millimetre) ceramic top coat, has a low thermal conductivity and, therefore, acts as a barrier against heat damage.