Influences of Bi_0.75Y_0.25O_1.5 addition on the microstructure and ionic conductivity of Ce_0.8Y_0.2O_1.9 ceramics

Abstract

A second phase of Y 2 O 3 -stabilized Bi 2 O 3 (Bi 0.75 Y 0.25 O 1.5 ,YSB) is introduced into Y 2 O 3 -doped CeO 2 (Ce 0.8 Y 0.2 O 1.9 ,YDC) as a sintering additive and the composite ceramics of 5,10,20,30, 40 wt%) are prepared through sintering at 1100°C for 6 h in air atmosphere. The YDC-xYSB ceramics are composed of both YDC and YSB with cubic fluorite structure, and no other impurity phases are detected in XRD patterns. The relative density of YDC-xYSB rises firstly for x ≤5 wt%, and then it declines with YSB addition from 5 to 40 wt%. The average grain size of YDC decreases from 270 nm to 85.7 nm with YSB addition from 0 to 40 wt%. The YSB phase segregates at the grain boundaries of YDC based on the TEM analysis result.The ionic conductivity of YDC-xYSB (x ≥5 wt%) is lower than that of YDC in the test temperature of 200°C-500°C, while it gradually exceeds that of YDC in 500°C-750°C. At 750°C, the conductivity of YDC-30%YSB (6.22 × 10 −2 S/cm) is 1.35 times higher than that of YDC (4.6 × 10 −2 S/cm). The YSB addition can improve the ionic conductivity of YDC in 500°C-750°C and decrease its sintering temperature. K E Y W O R D S bismuth oxide, composite ceramics, ionic conductivity, sintering aid, Y 2 O 3 -doped CeO 2 How to cite this article: Liang W, Meng B, Xiao Q, et al. Influences of Bi 0.75 Y 0.25 O 1.5 addition on the microstructure and ionic conductivity of Ce 0.8 Y 0.2 O 1.9 ceramics.