Electric current effect during the early stages of field-assisted sintering

The linear shrinkage during isothermal treatment in the early stages of conventional and field-assisted sintering of 8YSZ was analyzed. The results reveal that the application of a moderate electric current causes a remarkable acceleration of the self-diffusion kinetics, resulting in an enhanced densification. In addition, when an electric current is applied, two different field-assisted sintering regimes can be identified. The first one, observed at low currents (ie 5 mA/mm²), is associated to sintering shrinkage which follows the conventional trend () although the densification is accelerated. The second regime takes place when larger current are applied (J > 10 mA/mm²) and is described by a different sintering law, , this pointing out that the electric current causes the activation of alternative densification mechanisms when it exceeds a certain threshold value.