STUDY ON SURFACE DEFECT STRUCTURES OF ZRO2 AND SOME DOPED ZRO2 BY MEANS OF WORK FUNCTION MEASUREMENT

The work function change of the ZrO2 + 2% Y2O3 sintered pellet, caused by a change of the composition of the sweep gas, was measured using a high temperature Kelvin probe. The Pt reference electrode was calibra ted by using ZrO2 + 2%Y2O3 as a standard material. Work function chang es of undoped ZrO2 and Nb-doped ZrO2 (2%Nb2O5) were measured as a func tion of equilibrium oxygen partial pressure, P-O2. The thus obtained e xponents of P-O2, 1/n, were 1/6.2 and 1/33.6 for ZrO2 and ZrO2 + 2%Nb2 O5, respectively. These exponent values were discussed in terms of def ect chemistry of the surface layer. (C) 1997 Elsevier Science B.V.