Fig. 4: Macroscopic Joule heating response of a ceramic green body during flash sintering.
Macroscopic thermal and electrical behavior of 3YSZ sample as described by microstructurally averaging the Joule heating power density response of the simulated ceramic green body (see Fig. 2). Inset (a) shows the predicted sample temperature, Ts, as a function of furnace temperature, Tf, and sintering time. An external electric field of 60 V/cm and a constant heating rate of furnace, 10 K/min is applied. Inset (b) shows the different heating rate contributions to heating the sample: radiation heating (red), Joule heating (blue), and enthalpy of melting (green). Inset (c) shows predicted current density, 〈I〉, as a function of furnace temperature. The current density follows an Arrhenius relationship with the sample temperature till incubation time. The abrupt increase in conductivity after the incubation time defines a thermal and electrical runaway, which in turn defines the onset of the flash event.
