Flash sintering scaling-up challenges: Influence of the sample size on the microstructure and onset temperature of the flash event

The influence of sample size on microstructure, density, and onset temperature of the flash event was investigated for 3 mol% yttria-stabilised zirconia (3YSZ). Pellet samples with different height and constant diameter were flash sintered under an AC electric field. The larger the samples were, the lower was their flash onset temperature. Furthermore, a more heterogeneous microstructure was verified on larger samples followed by lower density. The influence of the samples' height on the thermal runaway and the thermal gradient within the samples are discussed as responsible for these effects