Phase Structure and Phase Stability Studies of La-Y Co-doped HfO₂Materials and Coatings

In this study, The 30 mol% La-Y co-doped HfO2 was prepared by solid-phase synthesis and the effect of the doping content of La element on the phase structure and high temperature phase stability was investigated by XRD. The results show that LaYSH is pyrochlore p-phase + fluorite c-phase when the doping content of La element is 6 and 9 mol%, and a single fluorite c-phase when the doping content is 0-3 mol%. After sintering at 1600 C for 50 h, 0, 1 and 2 LaYSH remained as a single fluorite c-phase, 3 LaYSH produced 2.54 wt% pyrochlore p-phase, and the pyrochlore p-phase content in 6 and 9 LaYSH decreased to varying degrees. The prepared 0, 1 and 2 LaYSH coatings all had a single c-phase and remained unchanged in the single c-phase when sintered at 1600 C for 50 hours, demonstrating their good high temperature phase stability.