Disc-shaped samples of 8 mol.% Y2O3-stabilized zirconia (YSZ) with two embedded Pt + YSZ circular electrodes and contacting Pt wires were made by sintering in air at 1500 degrees C. In one sample, four Pt probes were embedded for local electric potential measurements. Porous surface Pt electrodes were applied on the two exposed surfaces. The samples were heated in air over a temperature range from 800 degrees C to 900 degrees C. A DC voltage between 1 V and 1.7 V was applied across the surface electrodes and the embedded electrodes with the positive connected to the surface electrodes. This resulted in the formation of black zirconia between the two embedded electrodes by electrochemical pumping out oxygen. In the sample with embedded Pt probes, the local potential was measured as a function of time. (C) 2016 The Electrochemical Society. All rights reserved.