A SYNTHESIS METHOD OF TETRAGONAL STABILIZED ZIRCONIA

Fine ceramic powders of 2.8% mel Y2O3/ZrO2 were obtained by a chemical method based on the gellification with citric acid of a zirconyl salt and yttria followed by pyrolisis. This relatively unexpensive method enabled to obtain nanocrystalline tetragonal yttria stabilized zirconi a (TSZ) ceramic powders. Fine grained specimens were sintered in air a t temperatures between 1400 and 1600 degrees C. Sintered specimens as well as powders were characterized by X-ray diffractometry, thermograv imetric analysis, optical and scanning electron microscopies and by de nsity and Vickers microhardness measurements. Electrical characterizat ion of the specimens was performed with electrochemical impedance spec troscopy in a temperature range of 200-450 degrees C with frequencies varying between 1 Hz and 1 MHz. These results were compared with those obtained from commercial powders sintered under similar conditions.