Investigation on the phase stability, sintering and thermal conductivity of Sc_2O_3-Y_2O_3-ZrO_2 for thermal barrier coating application

摘要

Rare earth oxides co-doped zirconia have been developed for application in thermal barrier coating systems to promote the performance and durability of gas turbines. 8 mol%Sc_2O_3, 0.6 mol%Y_2O_3-stabilized ZrO_2 (ScYSZ) powder was synthesized by chemical co-precipitation method. The phase stability, sintering resistance and thermo-physical properties of ScYSZ and 8 wt%Y_2O_3 stabilized ZrO_2 (8YSZ) were investigated. The results indicated that both ScYSZ and 8YSZ show single tetragonal phase before heat treatment. After heat treating at l500℃ for 300 h, ScYSZ exhibits excellent phase stability with 100% metastable tetragonal (t') phase, whereas the content of monoclinic phase in 8YSZ reached 49.4 mol%. ScYSZ also exhibits higher sintering resistance and lower thermal conductivity than 8YSZ. ScYSZ can be considered to be explored as candidate material for TBC application.