Powder synthesis of nanocrystalline ZrO2-8%Y2O3 via a polymerization route

A Pechini process has been used for preparation of yttria-stabilized zirconia gels and powders. Thermal behavior of gel and relationships between processing parameters and structure and microstructure of the powders have been determine to use this route for the preparation of thin film of YSZ. The thermal behavior of the gel has been studied by both thermogravimetric (DTA/TGA) and mass spectrometry analyses. The decomposition progress is in several steps and is based on a thermally induced anionic redox reaction. The transformation from amorphous powder (the gel) into a crystallized homogeneous oxide phase corresponds to an endothermic and two exothermic peaks in the DTA curve; the first one at 168 degreesC is related to the evaporation of excess of ethylene glycol, the second peak at 300 degreesC corresponds to a superposition of two reactions : the decomposition of some organics and the crystallization of YSZ. The last exothermic peaks correspond to the pyrolysis of organics residuals. A series of yttria-stabilized zirconia powders with different agglomerate structures have been synthesized by altering the acid citric-ethylene glycol ratio (CA/EG). The gel with CA/EG = 2.4 yields nanostructured powders at 325 degreesC that is less porous and agglomerate with an average of 10-20 nm primary particles. Its specific surface area is around 55 m(2)/g. (C) 2001 Elsevier Science Ltd. All rights reserved.