Sc2O3-CeO2-ZrO2 electrolyte manufactured by Spark Plasma Sintering

Spark Plasma Sintering (SPS) is a new processing route that allows sintering of fully dense ceramics at relatively low temperatures in a very short period of time measured in only a couple of minutes. In the SPS process a graphite die is filled with the ceramic powders, and placed between lower and upper electrodes. A pressure and a pulsed direct current are applied to the sintering powders and the activation of the powders is achieved by the application of electrical discharges. For electrically conductive powders, heating up is mainly due to the Joule effect. For non-conductive powders heating is achieved through heat transfer from the die. Such external electric current leads to improved densification during sintering and requires a short time cycle. Additionally, the process eliminates absorptive gas and impurities present on the surface of the powder particles providing fully dense materials with much cleaner grain boundaries compared to samples produced by conventional sintering techniques such as presureless sintering.

The only SPS facility in the UK was recently set up at QMUL. It provides a unique chance to develop a SPS manufacturing route to produce dense single elements of lower temperature Solid Oxide Fuel Cells with improved electrical and structural properties. The goals of the proposed work are to: i) produce thin dense Sc2O3-CeO2-ZrO2 (ScCeZrO2) electrolytes by tape casting followed by either SPS or presureless sintering; ii) characterize and compare the microstructure and electrical properties of the developed electrolytes.