Preparation and properties of highly porous, biomorphic YSZ ceramics

Highly porous, biomorphic YSZ (yttria-stabilized zirconia) ceramics were manufactured by infiltration of zirconium-oxychloride (ZrOCl(2)(.)8H(2)O) sol into biological template structures derived from rattan and pine wood. 3-5 mol% yttrium nitrate (Y(NO(3))(3)(.)5H(2)O) was added to the sol to stabilize the tetragonal ZrO(2) phase. After vacuum-assisted infiltration, the specimens were pyrolysed at 800 degreesC in N(2) atmosphere. Repeated infiltrations and subsequent annealing in air at temperatures up to 1550degreesC yields the burn out of the biocarbon template and resulted in the formation of biomorphous YSZ ceramics, which maintained the microstructural features of the biological preform. Depending on the type of the biological template as well as the processing parameters, biomorphic ZrO2 ceramics with an unidirected pore morphology and a large variety of microstructures can be obtained. (C) 2004 Elsevier B.V. All rights reserved.