An online multi-spectrum-based method for evaluating thermal insulation performance of smart thermal barrier coatings

The increasing working temperature of aero-engines demands the development of high-performance thermal barrier coating (TBC). However, one inherent obstacle is the precise evaluation of thermal insulation performance, which affects TBCs’ full lifespans. Here, we report an online multi-spectrum-based method that relies on the temperature-dependent laser-induced phosphorescence from rare earth ions doped into the ceramic coat for precisely evaluating the thermal insulation performance of smart thermal barrier coatings (STBCs). Taking a 20-μm-thick STBC at the thermal gradient of 1.0 K/μm as an example, the evaluation accuracy can be improved by 10 K when this method with high versatility and adaptability is utilized. Furthermore, a complete STBC full-lifespan management framework is established to realize intelligent and synergistic operations. This study sets up a paradigm for performance evaluation, life prediction, and health prognostics throughout the TBC's full lifespan, which can advance the development of aero-engines and related rotating machinery.