Study on liquid phase flash sintering of 3YSZ assisted by ZnO-Cu2O eutectic

Abstract

This work examines liquid phase flash sintering (LPFS) of 3 mol% yttria-stabilized zirconia (3YSZ) co-doped with 1-10 wt% ZnO-Cu2O eutectic (CZ). During flash sintering, Joule heating rapidly elevates temperature beyond the CZ eutectic point (similar to 1100 degrees C), generating a liquid phase that drives accelerated densification. XRD analysis demonstrated substantial solubility of Cu+ and Zn2+ ions into the zirconia lattice, which lowered the theoretical density while achieving optimal densification (>96% relative density) at 2.5 wt% CZ. XPS revealed elevated oxygen vacancy concentrations in flash sintered samples relative to those conventionally sintered. EIS indicated that the 2.5 wt% CZ variant exhibited superior ionic conductivity and minimal activation energy. Finite element analysis confirmed average temperatures during flash sintering higher than the eutectic point. Overall, these findings validate moderate CZ co-doping paired with flash sintering as a strategy to engineer defect chemistry and microstructure, enabling breakthroughs in SOFC electrolytes and low-temperature ceramic processing.