Influence of rare earth elements additions in YSZ ceramic coatings of thermal barrier coatings on lattice distortion

Geometry optimization of zirconia added with rare earth elements is carried out by means of the first principle method based on plane-wave pseudopotential theory. X-O bond length, lattice constant, and atomic bond populations are analyzed. The calculation results are analyzed by comparing with the experiment data. It is found that with the addition of rare earth elements, expansion distortion occurres in zirconia crystal cell, the X-O bond length becomes longer and the bond population becomes smaller, which will increase the phonon dispersion and reduce the lattice vibrating frequency and the thermal diffusion coefficient. Within the range of covalent radium used for the calculation, the larger the covalent radium of the rare earth element, the larger the expansion distortion, and the smaller the population, which will be benefit for reducing the thermal diffusion coefficient.