Flash sintering of one-step synthesized NiO-Ce0.9Gd0.1O1.95 (NiO-GDC) composite

Abstract

For the first time, the flash sintering process was successfully applied on NiO-Ce0.9Gd0.1O1.95 (NiO-GDC) composite, satisfactorily obtained from a 'one-step' synthesis method, in the temperature range from 105 °C to 216 °C using an electrical field range from 130 to 40 V cm-1. The use of a high electric field and high current densities increases the instability of the process, producing a high concentration of current in the material and presenting typical solidification microstructures, which is a sign of the high concentration of power under these conditions. The decrease of the electric field to 50 V cm-1 allows highly densified samples to be obtained at temperatures as low as 200 °C using a current density of 260 mA mm-2. The electrical conductivity of densified samples prepared at different current densities shows a high conductivity in the temperature range of 400-650 °C, in which it reaches up to 0.23 (Ω cm)-1 at 650 °C.