Effect of Electric Field/Current on Sintering Behavior of Yttria during SPS Processing

Effect of the electric current on the densification behavior of yttria (Y2O3) and zirconia (3YSZ) powders during the spark-plasma-sintering (SPS) process has been examined. The powders were densified by the SPS device under two types of die set-up; one is a conductive normal set-up, in which the powders loaded into a graphite die were sandwiched by carbon papers, another is an insulation set-up, in which the powders were sandwiched by BN powder in the die. For the 3YSZ powder, the shrinkage is independent of the die set-ups. Whereas for the Y2O3 powder, on the other hand, it was apparently accelerated during the initial and intermediate sintering stages and completed at more than 100 oC lower temperature in the normal die set-up than in the insulation set-up. It is expected that the DC pulsed current applied during the SPS processing enhanced the sintering of the Y2O3 powder. This suggests that during the SPS processing, applied pulsed electric field/current is likely to contribute to the sintering of Y2O3 ceramics.