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This study aims to understand the effect of the electrical field on microstructure evolution during field‐assisted sintering or spark plasma sintering (FAST/SPS) of 10 mol% gadolinium‐doped ceria (GDC) with experimental and numerical methods. The novelty of this study has been the observation of enhanced grain growth in the region closer to the anode, even under FAST/SPS conditions with electrical fields less than 5 V/cm. The grain growth kinetics, including determination of activation energy and grain‐boundary mobility, were analyzed along the cross section of the samples for different temperatures and dwell periods. With an increase in distance from the anode, reduction in the activation energy for grain growth and grain‐boundary mobility was observed. These observations attributed to the attraction of oxygen ions to the anode region under an electrical field with an increase in defects along the grain boundaries. Thereby an increase in the grain‐boundary mobility and larger grains in that region were observed. A homogenous microstructure was observed in a case where the current did not flow through the sample. Furthermore, a numerical strategy has also been developed to simulate this behavior in addition to heat generation, heat transfer, and densification using Finite Element Methods (FEM) simulations. The simulation results provided an insight into the presence of a potential difference across the cross section of the samples. The simulation results were also in good agreement with the experimental observations.

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As a promising sintering technique, flash sintering utilizes high electric fields to achieve rapid densification at low furnace temperatures. Various factors can influence the densification rate during flash sintering, such as ultrahigh heating rates, extra‐high sample temperatures, and electric field. However, the determining factor of the densification rate and the key mechanism during densification are still under debate. Herein, the densification and grain growth kinetic during flash sintering of 8 mol% Y2O3‐stabilized ZrO2 (8YSZ) is studied experimentally and numerically using finite element method (FEM). The roles of Joule heating and heating rate on the densification are investigated by comparing flash sintering with conventional sintering. An apparently smaller activation energy for the material transport resulting in densification is obtained by flash sintering ( =424 kJ mol−1) compared to the conventional sintering ( = 691 kJ mol−1). In addition, a constitutive model is implemented to study both the densification and the grain growth during flash and conventional sintering. Furthermore, the effect of electrical polarity on the density and the grain size evolution during flash sintering of 8YSZ is also investigated. The simulation results of average density and grain size inhomogeneity agree well with the experimental data.

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