ELECTRICAL-CONDUCTIVITY IN THE SYSTEM ZRO2-Y2O3-SC2O3

In order to clarify the reason why the electrical conductivity of zirc onia solid solution decreases abruptly, when it was highly doped with aliovalent oxide, the system (Y1-xScx)(0.3)Zr0.7O1.85 was studied by m eans of DC- and AC-conductivity measurements. Y0.3Zr0.7O1.85 (x = 0.0) showed lower conductivity than that of Y0.2Zr0.8O1.90. It was found t hat the decrease in the electrical conductivity was due to the presenc e of a grain boundary phase as a 'microdomain' by the complex impedanc e measurements. On the other hand, the substitution of Sc3+ for Y3+ in creased the electrical conductivity, and at the same time, the grain b oundary phase disappeared. This fact suggested that the high level dop ing induced a second phase at the grain boundary, resulting in the dec rease in the electrical conductivity. (C) 1998 Elsevier Science B.V. A ll rights reserved.