Strengthening of Gadolinia‐Doped Ceria (Ce 0.80 Gd 0.20 O 2‐δ ) Thick Ceramic Membranes with Co‐Doping of 1 mol% CuO

Nano‐sized Ce 0.79 Gd 0.2 Cu 0.01 O 2‐δ ( CGCO ) and Ce 0.80 Gd 0.2 O 2‐δ ( CGO ) powders were synthesized via a facile PVA ‐assisted combustion method. Full densification can be achieved at much lower temperature (950°C) with minor CuO doping (1 mol%, CGCO ) as compared with CGO (1400°C); meanwhile, mechanical strength can be enhanced with CuO co‐doping. The CGCO sintered at 1100°C possesses a relative density of 98.80% and biaxial flexural strength of 302 ± 35 MP a, which is higher than those of CGO sintered at 1400°C (96.43%, 250 ± 39 MP a). A tentative microstructural analysis indicates that this strength enhancement can be attributed to a change in fracture mode from partial to complete transgranule dominant.