Improved Bond-Coat Layers for Thermal-Barrier Coatings

Current production thermal-barrier coatings (TBCs) have been shown to be capable of reducing the average temperatures of metallic components by 50 to 80 °C and hot-spot temperature by up to 140 °C. This substantial temperature reduction has been used to extend the life of metallic components in aircraft turbines. However, for critical applications aimed at improving engine performance where significantly higher temperatures are involved, higher-durability TBCs are required. An improved bond coat incorporating metallic and cermet layers has been demonstrated to increase the thermal-fatigue life of a plasma-sprayed thermal-barrier coating (TBC) by a factor of two or more. These TBCs can be applied to components in gas turbines and in diesel engines.