Influence of doping elements on thermo-physical properties of co-doped strontium zirconate for potential thermal barrier coatings

Abstract

Strontium zirconate is a promising material for thermal barrier coatings due to some excellent properties. New four co-doped strontium zirconate with lower thermal conductivity and higher thermal expansion coefficient were synthesized in this study. Sr(Zr0.9Y0.05Yb0.05)O2.95 (SZYYb) with the smallest difference in ionic radius and mass has lowest thermal diffusion coefficients mainly due to the effect of extrinsic phonon scattering mechanisms, including lattice distortion and grain size. The electronic structures of four co-doped SrZrO3 were analyzed by first-principles calculations. The findings suggested that the difference in bond strength caused by different doping affected the differences in the lattice constant, which led to the highest thermal expansion coefficient of SZYYb.