INFLUENCE OF FORMATION PH AND GRINDING OF PRECURSORS ON COMPACTION AND SINTERING BEHAVIORS OF 3-MOL-PERCENT Y2O3-ZRO2

Tetragonal stabilized zirconia samples, 3 mol % in Y2O3, are prepared by pyrolysis up to 900-degrees-C of gelatinous precursors formed by hy drolysis of aqueous solutions containing both zirconium and yttrium ac etates. Such prepared powders are white, but still contain about 0.5 w t % in carbon. The increase of the end hydrolysis pH from 3.9 to 10.0 has a very limited influence on the evolution of the density of sample s during cold compaction and then sintering by heating at 1500-degrees -C The ball-milling of the precursor before pyrolysis decreases the si ze of the agglomerates formed at 900-degrees-C without modifying the s ize of crystallites. The size of large interagglomerate pores is also decreased The whole porosity remains constant and only the distributio n between open and closed porosity is modified. The modification of th e morphology eases the gaseous release during heating and leads to a m ore significant shrinkage and consequently to a higher density after s intering.