Thermal barrier coatings (TBCs) have been widely used to protect the superalloy components from the hot gas stream in gas turbine engines. Driven by the higher inlet temperature of modern gas turbine engines for higher efficiency and less harmful gas emission, exploration of TBC new materials and thermal radiation effects of TBCs have recently attracted more attentions. This research explored the potential application of gadolinium zirconate as a promising new TBC material due to its lower thermal conductivity, higher phase stability, and higher CMAS-resistance than conventional YSZ material. The thermal cycling tests were performed using a novel test rig which was designed to mimic the complex working condition of TBCs, and the thermal radiation properties were characterized in the wavelength range where turbine engine thermal radiation is most concentrated. This book is suitable for both beginners and professions in the field of TBCs, as it covers both the brief introduction of TBC system, deposition methods, recent development and the in-depth analysis of failure mechanisms and different models to determine the coating absorption and scattering coefficients.