Electrical conductivity of tetragonal stabilized zirconia

The electrical conductivity change on annealing for tetragonal stabilized zirconia (TZP) was studied with the help of a.c. impedance dispersion analysis techniques. The dependences of the conductivity on annealing time at 1000 ° C and on temperature cycling between room temperature and 1000 ° C were investigated. A decrease in conductivity of about 30% at 1000 ° C of TZP with 3 mol% Y₂O₃ was observed during the first 200 h of annealing at 1000 ° C, and no change was observed during further annealing. A similar result was observed for TZP with 2.9 mol% Sc₂O₃. For TZP with 3.0mol% Yb₂O₃, the conductivity decreased gradually during an annealing time of over 2000 h. The impedance dispersion analysis at lower temperature suggested that the decrease in electrical conductivity by annealing at 1000 ° C could be attributed to the increases of both grain boundary and intragrain resistance. No monoclinic phase was observed for the samples annealed at 1000 ° C for 2000 h. On the other hand, a trace of a monoclinic phase was found for TZP with 3mol% Y₂O₃ after the 50th temperature cycling, but no significant decrease in conductivity was observed with the cycling.