Robust synthesis of yttria stabilized tetragonal zirconia powders (3Y-TZPs) using a semi-continuous process in supercritical CO2

The increasing interest in supercritical fluids for synthesizing inorganic materials stimulated the development of new processes for the continuous production of nanopowders. A semi-continuous PCA process (Precipitation with Compressed Anti-solvent) coupled with sol-gel reactions has been developed in this work for the synthesis of yttria-stabilized tetragonal zirconia powders (3Y-TZPs) with controlled morphology, structure and microstructure. Both precursor injection and mechanical stirring rates were found to be key parameters for controlling the mean particle size and size distribution. Powders consisting of spherical nanoparticles (from 50 to 130 nm) with a nanophase substructure (5-7 nm) were obtained at 350 degrees C, 30 MPa. This multi-scale structure leads to relatively high specific surface areas (up to 195 m(2)/g), and powder sintering starting at low temperature (around 400 degrees C). (C) 2013 Elsevier B.V. All rights reserved.