Local field strengths during early stage field assisted sintering (FAST) of dielectric materials

The role of an applied electric field during the densification of ionic ceramics is still being debated. Here we describe how the polarization of a dielectric material contributes to the field strengths at particle surfaces and interfaces during the initial stage of sintering. Using numerical models, it is shown that significant increases in local field strengths can be expected during initial neck formation and continue, with decreasing contribution, through approximately half of the first stage of sintering. The field strengths achievable in common commercial and custom lab-scale electric field assisted sintering systems are found to be comparable to those at which electric fields have been shown to enhance the densification behavior of ionic ceramics.