Characterization of microstructure and thermal properties of Gd2Zr2O7-type thermal barrier coating

We present herein a characterization of the microstructure and thermal properties of thermal barrier coatings (TBCs), which we obtained via plasma spraying of powder Gd2Zr2O7. By using X-ray diffraction (XRD) and electron backscatter diffraction (EBSD), we evaluated the phase composition of a ceramic layer and estimated the ceramic-layer stress state by the sin2ψ method. The tests revealed that the TBC layer consisted of a single-phase structure of Gd2Zr2O7, namely, an Fd3m lattice. The thermal diffusivity of the outer ceramic layer was determined based on a bilayer model and corrected with a factor to account for the presence of pores. The results reveal that the use of the standard parameters in a standard spraying process gives good-quality Gd2Zr2O7 TBCs with a thermal conductivity considerably lower than 8YSZ-type TBCs.