Sintering behaviour of the protonic conductors BaZrxCe0.8-xLn0.2O3-δ (x=0.8, 0.5, 0.1; Ln=Y, Sm, Gd, Dy) during the solid-state reactive-sintering process

The protonic conductors BaZrxCe0.8-xLn0.2O3-δ (x=0.8, 0.5, 0.1; Ln=Y, Sm, Gd, Dy) were successfully prepared using a solid-state reactive-sintering method. NiO (1 wt.%) was added as a sintering aid, and it was proven that NiO produced tremendous enhancement in the densification process. The morphologies of the variously doped BaZr0.8Ln0.2O3-δ, BaZr0.5Ce0.3Ln0.2O3-δ and BaZr0.1Ce0.7Ln0.2O3-δ ceramics, as well as their sintering behaviour, were investigated. The results show that the Ce content in the BaZr0.8Ln0.2O3-δ, BaZr0.5Ce0.3Ln0.2O3-δ and BaZr0.1Ce0.7Ln0.2O3-δ compounds influences the sintering temperature significantly, and a larger Ce content will lead to a lower sintering temperature. In addition, ionic radii of the dopants that are similar to the ionic radii of the B-site will also result in a lowered sintering temperature. Based on the present study, NiO has no influence on the lattice parameters.