Nanostructure, Nanochemistry and Grain Boundary Conductivity of Yttria-Doped Zirconia

Abstract

This work was directed at a comprehensive study of the role of the nanostructure and nanochemistry on the transport properties of yttria-stabilized zirconia. Alumina additions lead to a decrease of sgb when the samples have clean grain boundaries, while sgb goes through a maximum in samples having glassy grain boundaries. The differences were attributed to the strong interaction between Al2O3 and SiO2 impurities leading to a glassy phase depletion at the grain-boundaries, due to a change in wettability. Moreover, XPS analyses show that Si and Y segregate near these interfaces according to a kinetic demixing process, explaining why a faster cooling rate after sintering has a beneficial effect on sgb.

Pseudopartial Grain Boundary Wetting: Key to the Thin Intergranular Layers

“…In Ref. 125 two YSZs (called Z C and Z F ) were sintered from powders prepared through two different processing routes. In samples Z C the glassy phase wetted GBs and GB triple junctions.…”

Impact of Spark Plasma Sintering Conditions on Ionic Conductivity in La1.95Sr0.05Zr2O7-δ Electrolyte Material for Intermediate Temperature SOFCs

“…Other more specific impacts could be attributed to the grain size and the inter-particle neck size (13) or the pore structure (14). Moreover, high resistivity in the grain boundaries is observed for many ionic conductors and is commonly attributed to blocking impurity phases at the grain boundaries (15,16). Different sample preparation processes may cause all of these factors leading to an increase in resistivity.…”