Rapid joining of heterogeneous ceramics with a composite interlayer under the action of an electric field

Abstract Joining heterogeneous ceramic oxides (e.g., zirconia (ZrO2), alumina (Al2O3)) is important to widen their application horizon. Unfortunately, the joining of heterogeneous ceramics is hindered by dissimilar microstructures. Herein, a composite of 3 mol.% Y2O3-stabilized ZrO2 (3YSZ) and Al2O3 was used as interlayer (ZrO2-Al2O3, ZA) to form 3YSZ-ZA-Al2O3 joint under the influence of an electric field, which reduced the joining temperature and joining time. The joint strength attained steady state with current and joining time being beyond the threshold. The strength of the 3YSZ-ZA interface decreased and that of ZA-Al2O3 interface increased with increasing Al2O3 content in ZA. The strength of the 3YSZ-ZA interface is higher than that of the ZA-Al2O3 interface under the same joining parameters, and this was ascribed to the higher oxygen vacancies diffusion rate in 3YSZ than in Al2O3. The joint was formed by the connection of 3YSZ and Al2O3 ceramics to the respective grains in ZA.