Flash event have been attracted many attentions because it can accelerate the sintering behavior of ceramic powders. The flash event has been reported to work effectively not only to the sintering, but also to other high temperature phenomena, such as deformation, joining and healing. For example, 3Y-TZP exhibits the superplastic flow of >150% at lower temperatures under the flash event with DC current. However, the effects of the flash event on the high temperature phenomena have widely been examined in the DC current condition, but limited in the AC current condition. Irrespective of the many research works, the effect of electric field/current on the high temperature deformation is still unclear, especially in the AC conditions. The present study, therefore, was carried out to examine the current effects on the creep behavior of polycrystalline zirconia ceramics under the DC and AC current conditions.

By applying the AC or DC electric power higher than a critical value of >100 mW/mm³, the flash event similar to that of powder sintering occurs even in dense 8Y-CSZ ceramics. The electric current enhanced the rate of deformation to several times as compared to those without the current conditions. Although the sample temperatures increase with the currents due to the Joule heating, the enhanced deformation cannot be interpreted only by the increment of sample temperatures. In addition, even at the same temperature, the increase in the deformation rate is significant in the AC current than in the DC current. In the presentation, we will report the more detailed current dependent creep behavior at wide range of testing conditions.

This work was financially supported by JST CREST (JPMJCR1996) and by KAKENHI (20H02444), Japan.