Effect of electric field (2.45Â GHz) on sintering behavior of fully stabilized zirconia

Numerous reports presented in the literature have shown that microwave sintering results in reduction of processing temperature/time required for densification in some materials when compared to conventional sintering. While faster sintering regimes may look promising, it is important to understand why microwaves appear to enhance the sintering phenomena. It is speculated that the electric field associated with microwave energy is enhancing flux, leading to accelerate densification. Enhancement in flux is a result of an increase in driving force, in the transport coefficient, or both. This study examines the sintering behavior of 8 mol% yttria-zirconia at various values of electric field intensity (frequency being constant, 2.45 GHz) to understand whether the driving force or transport coefficient terms in the flux equation lead to enhanced densification. The transport coefficient term shows an increasing trend with an increase in electrical field intensity. These results indicate that the underlying reason for the increase in the transport coefficient term is due to a shift in diffusion path, from volume to grain boundary diffusion.