Thermal transport and structural modulations in Isovalent co-doped zirconium dioxide: An integrated experimental-computational investigations

Engineering point defects in Zirconium dioxide through controlled doping can tailor its phonon scattering and thermal transport. With integrated theoretical models and experiments, a comprehensive understanding of dopant driven property evolution can optimize its performance in extreme environments. Coupling the first principles calculation with experimental validation provides a reasonable strategy to correlate the defect chemistry with the thermodynamics across the coating. The Ce, Ti co-doped ZrO 2 models and coatings exhibit tunable structural, electronic, optical, and thermal properties governed by dopant induced defect engineering. In the partial density of states (PDOS) analysis, the static disorder potential and the dynamic electron-phonon coupling strength correlate the structure with the phonon conduction. The Zr0 .9204 Ce 0.0293 Ti 0.0493 O 2 model provides the most diffuse and strongly redistributed density of states spectrum with pronounced defect-state interaction and partial electronic localization. Phonon density of states reveals that progressive doping in ZrO 2 transformed the lattice from an ordered phonon-conducting system into a highly disordered phonon-blocking structure. Without any mixed phase, the X-ray diffraction peaks confirm the uniform single phase of all samples. The Energy X-ray Dispersive Spectroscopy reveals the successful incorporation of Ce and Ti in ZrO 2 matrix and the uniform elemental mapping provides the evidence of spatial scattering centers (point defects, strain fields and mass mismatch fields) distribution across the sample. The overall thermal conduction in both theoretical and experimental findings is consistent for all models and samples. The CeTi-ZrO 2 model (theoretical) and sample (experimental) demonstrates lower thermal conduction compared to the mono-doped systems. Moreover, the increasing Ce, Ti concentration further reduced the thermal conductivity. The theoretical model (Zr 0.75 Ce 0.125 Ti 0.125 )O 2 exhibits the thermal conductivity values of 0.52 W m −1 K −1 at 200 K and 0.95 W m −1 K −1 at 1400 K. The experimental Zr 0.9204 Ce 0.0293 Ti 0.0493 O 2 sample possess the minimum thermal conductivity of 0.46 W m −1 K −1 (298.15 K) and maximum of 0.50 W m −1 K −1 (1523.15 K). The reduced thermal conductivity of Zr 0.9204 Ce 0.0293 Ti 0.0493 O 2 sample is attributed to the lattice dynamics, compositional disorder, defect scattering, phonon scattering, and sample microstructure.