Effects of Synthetic Parameters in Pechini Method on the Formation and Properties of (ZrO_2)_(0.92)(Sc_2O_3)_(0.08) Solid Solution

摘要

Homogeneous （ZrO2）0.92（Sc2O3）0.08 solid solution in fluorite cubic structure was prepared from the gels with altered molar ratios of citric acid （CA） to metal ions （M） and ethylene glycol （EG） via a polymerization route （Pechini method）. Due to the enhanced chemical homogeneity （high level of mixing of metal ions and ligands） in the polymeric gels, Sc-doped zirconia can be crystallized at temperatures as low as 400 ℃. During the evolution from amorphous gel to the crystallized （ZrO2）0.92（Sc2O3）0.08 fine powder, the bonding nature between carboxylate groups and Zr/Sc cations changed: unidentate→bridging→ionic upon calcination. The molar ratios of CA/M （1～4） and CA/EG （0.2～4） were demonstrated to affect the thermal behavior of the gels and thus the particle properties of the derived nanoparticulate oxide powders （including particle size and surface area）. The as-sintered sample compacted from the nanosized powders prepared by calcining the gel with the highest content of organics （CA/M=4 and CA/EG=0.2） exhibited the best sinterability and the highest oxide ion conductivity.