Effect of Ca-doping on the structural and electrical properties of CuY1−xCaxO2 (0 ≤x ≤0.10) ceramics

Delafossites CuY1−xCaxO2 (0 ≤x ≤0.10) ceramics have been prepared by solid state reaction using Cu2O, Y2O3 and CaCO3. Liquid phase sintering, which obviously accelerates the reaction speed of Cu2O–Y2O3–CaCO3 system and promotes the formation of CuYO2 phase is evidenced for the Ca-doped samples. During the sintering process, CuO can react with CaO to form two intermediate compounds, CaCu2O3 and Ca2CuO3, which decompose into CaO and liquid phase during 1273–1323 K. In the dopant range of 0 ≤x ≤0.10, both electrical conductivity and density of the samples are increased by Ca-doping. The room temperature conductivity of CuY0.94Ca0.06O2 is more than four orders of magnitude higher than that of CuYO2.

Research highlights
► The origin of intermediate liquid phase appeared during the sintering process of Cu2O–Y2O3–CaCO3 system and its contribution to the formation of CuYO2 phase.
► The effect of Ca-doping on the microstructure and electrical properties of CuY1−xCaxO2 (0 ≤x ≤0.10) ceramics.