Thermally stimulated depolarization processes in zirconia toughened alumina ceramics

In this paper, the zirconia toughened alumina (ZTA) ceramics were fabricated by pressureless sintering method. Dielectric relaxation characteristics of both alumina and ZTA ceramics were investigated using thermally stimulated depolarization current (TSDC) method and the relaxation parameters were calculated from the experimental TSDC curves. In addition, the relationship between zirconia doping and dielectric relaxation properties was analyzed. The results showed that doping of zirconia can affect the defect dipoles distributions in ZTA ceramics, and introduces a new relaxation peak at 478K. This new relaxation process may be attributed to the reorientation of dipoles of dopant and oxygen vacancy pairs generated in cubic zirconia grains.