Electrical field assisted sintering of polycrystalline Yttrium doped Ceria investigated by Sinter-forgingWednesday (26.09.2018) 15:15 - 15:30 S1/03 - 283 Part of:
The production of traditional and advanced ceramics is an energy-intensive activity, which is owed to high heating temperatures and long holding times to activate diffusional processes necessary for densification. Electric field assisted processing has the potential to significantly reduce the costs of required heating treatments and to yield specific microstructures which are not obtainable by other methods. The role of electric fields in the densification and coarsening of oxide ceramics is still under debate. By using a sinter-forging device equipped with a power source, it was possible to investigate and field assisted sintering process by quantifying uniaxial viscosity, viscous Poisson’s coefficient and sintering stress of oxide ceramics. Ceramic pellets were prepared from commercial nano powder, which were calcined and milled to improve the sintering behavior. The sintering parameters of the ceramic pellets were measured without / with electrical field (30 V/cm and 10 V/cm), considering the additional Joule heating and keeping the sample temperature constant while varying the applied mechanical load. The effect of the electrical field on both uniaxial viscosity and sintering stress were observed, the electrical fields were lower than that required for flash sintering. This explains why the sintering is enhanced under electrical field. Microstructures of the specimen were investigated by SEM and TEM, and correlated to the electrical properties of the samples measured by Electrochemical Impedance Spectroscopy.