Phase stability and thermal conductivity of ytterbia and yttria co-doped zirconia

摘要

Rare earth oxides doping has been extensively investigated as one of the effective methods to lower thermal conductivity of 4.55 mol% Y2O3stabilized ZrO2（YSZ） thermal barrier coatings（TBCs）.In the present work,5–6 mol% Yb2O3and Y2O3co-doped ZrO2ceramics were synthesized by solid reaction sintering at 1600 1C.The phase stability of the samples after heat treatment at 1500 1C was investigated.Yb2O3and Y2O3co-doped zirconia,especially when Yb2O3/Y2O3≥1,contained less monoclinic phase than single Yb2O3or Y2O3phase doped zirconia,indicating that co-doped zirconia was more stable at high temperature than YSZ.The thermal conductivity of the 3 mol% Yb2O3+3 mol% Y2O3co-doped ZrO2was 1.8 W m 1K 1at 1000 1C,which was more than 20% lower than that of YSZ.