Influence of microwave-assisted hydrothermal treatment on the properties of nickel oxide-zirconia based composites

Abstract

The influence of a microwave-assisted hydrothermal treatment (MWH) on the properties of NiO–ZrO2:8 mol%Y2O3–CeO2 composite was investigated. The composites were prepared by coprecipitation of nickel and cerium salts in a suspension of ZrO2:8 mol%Y2O3 (YSZ). Simultaneous thermogravimetric and differential thermal analysis revealed that the MWH promotes the crystallization of Ni(OH)2, as confirmed by X-ray diffraction. The sintering behavior of ceramic compacts was influenced by the MWH treatment, which contributed to slightly higher final apparent densities. Impedance spectroscopy measurements revealed that the electrical properties of sintered composites exhibit characteristics of mixed-ionic–electronic conductors, a feature that was suppressed in the samples that underwent MHW treatment. Such an effect evidences the influence of hydrothermal treatment on the final microstructure of the composite.