Ageing behaviour of zirconia stabilised by yttria and manganese oxide

The effect of Mn on the structure, lattice parameter and conductivity has b een investigated for near-cubic YSZ with an yttrium content slightly under 8 mol% Y2O3. The structure and chemistry of the material were studied both as sintered, and also after prolonged heat treatments at 850 and 1000 degre esC, using x-ray diffraction, electron microscopy, impedance spectroscopy a nd d.c. conductivity measurements. In the latter case, the measurements wer e made in-situ during ageing. At 1000 degreesC and for Mn additions above a bout 2 mol% YSZ is found to be stabilised as the cubic structure, and there by the conductivity is also stabilised. However, at all temperatures studie d, the presence of Mn considerably reduces the ionic conductivity of YSZ. ( C) 2001 Kluwer Academic Publishers.