Mechanism analysis of arc-induced flash sintering of 3YSZ at room temperature

Flash sintering (FS) is an ultrafast sintering method with low energy consumption and facile operation even at room temperature. Research has shown that the FS of 3 mol.% yttria-stabilised zirconia (3YSZ) at room temperature is induced by the appearance of an electric arc at both ends of the sample. In this study, we experimentally observed the arc-induced FS of 3YSZ, simulated the arc generation process based on magnetohydrodynamic equations, and analysed the arc-induced FS mechanism from the perspectives of heat conduction and current distribution. The simulation results showed the surface-flashover-induced microsecond-level generation of the arc. The results also demonstrated that the electrical conductivity of the sample varied with the temperature distribution due to the thermal conductivity of the sample, which resulted in the occurrence of arcs and arc-induced FS. Therefore, increasing the thermal and electrical conductivities of a sample can improve the experimental success rate of FS at room temperature.