WEB Current rate controlled flash sintering of Gadolinium doped ceria with tailored microstructure
Recently, current rate controlled flash sintering was introduced as alternative to established voltage-to-current control mode. Due to its mixed ionic and electronic conductivity, Gadolinium doped ceria (GDC) is a good candidate for demonstrating the potential of this novel operation mode. Therefore, dog bone shaped GDC samples were placed in a tube furnace and heated to 680°C. Current rate was linearly increased at well-defined rates in the range between 20 and 1000 mA min-1 to a maximum current density of 200 mA min-1. The electric field is self-generated by the resistivity of the sample. Drop of electric field indicated the on-set of the flash event. Microstructural investigations reveal that current rate controlled flash sintering increases the homogeneity of the grain size distribution and enables to tailor the grain size. Furthermore, it is expected that this novel operation mode ease scaling up of flash sintering technique by reducing the risk of hot spot formation.