Applications of synchrotron-based X-ray diffraction in investigating thermal barrier coatings

Thermal barrier coatings play crucial roles in protecting the hot end components of aero-engines against high-temperature erosion. They must suffer extremely harsh environments including high temperatures, heavy loads, and large internal temperature gradients, which would result in various complex failures. Therefore, it is important to unveil these failure mechanisms to minimize and even prevent them for obvious reasons. Strain/stress evolution between different layers and foreign material erosion are the main failure mechanisms of thermal barrier coatings, which are well suited to be investigated using synchrotron X-ray diffraction. With its tunable energy, high flux, and many other advantages, synchrotron-based X-ray diffraction has become an advanced non-destructive characterization technique for engineering materials yielding important information including their compositions and residual stress which also provides spatial and temporal resolution that is vital for understanding their service performance. This paper presents a concise review of the applications of synchrotron-based X-ray diffraction in investigating thermal barrier coatings to explore their failure mechanisms.