Rapid sintering protocol produces dense ceria-based ceramics

We report on a rapid sintering protocol, which optimizes the preparation of 0-29 mol% Gd-doped ceria ceramics with density ≥98% of the theoretical crystal lattice value. The starting material is a nanometer grain-sized powder prepared by carbonate co-precipitation and calcined with minimal agglomeration and loss of surface area. Slow (5°C/min) heating of the green-body from 500°C to the optimum temperature of rapid sintering ((Formula presented.), dwell time <1 minute) followed by 20°C/min cooling to 1150°C with 6 minutes dwell time, produces maximum pellet density. (Formula presented.) increases from 1300 to ~1500°C with increase in Gd-content, while the average grain size in the maximally dense pellets, as determined by scanning electron microscopy, ranges between 600 nm and ~1 μm. For each doping level, the logarithm of the average grain size decreases linearly with 1/T₁. By avoiding extended exposure to sintering temperatures, this protocol is expected to minimize undesirable Gd segregation.