Yttria stabilized tetragonal zirconia polycrystals (YTZP) were introduced to the biomaterials world due to its advantageous properties such as superior strength, toughness and wear resistance. The main application of this ceramic biomaterial is in the manufacture of ball heads for total hip replacements (THR) and dental restorations. In this study, 3Y-TZP powders were prepared by a simple sol-gel rout and its characteristics were evaluated. Appropriate amount of zirconium oxide chloride, ZrOC1 2 .8H 2 O, and yttrium nitrate, Y(NO 3 ) 3 .6H 2 O, to reach 3mol% yttrium oxide in final product, were mixed in anhydrous ethanol on a magnetic stirrer. After drying the obtained gel, it was calcined at different time and temperatures. The thermal behavior of the dried gel was investigated by stimulated thermal analysis (STA). Phase identification, particle size and its distribution and microstructural investigation were performed respectively using X-ray diffraction technique (XRD), electron microscope (SEM, TEM) and zeta-sizer. Nitrogen gas adsorption was also utilized to evaluate the BET specific surface area of the synthesized powder. The result of thermal analysis of dried gel showed no thermal effect after 600 ° C so the optimum calcinations temperature was determined as 600 °C. The XRD pattern of dried gel showed that the sample was quasi-amorphous while the XRD pattern of calcined powders revealed that the diffraction peaks are characteristics of tetragonal zirconia phase which shows that TZP has been obtained. Crystallite size of the powder evaluated by the Scherer equation and x-ray diffraction data is about of 20 nm. SEM and TEM studies respectively confirm the presence of agglomerates in powders with average size about 80 nm and crystallites of about 20 nm. Increasing the calcination temperature up to 1200 ° C did not cause formation of any new phase in the structure of powder. Crystallite growth due to the increase in calcination temperature was only up to 36 nm. These facts show that the synthesized powders have a very good thermal stability and remain nano-crystal even at high temperature near sintering one. Furthermore results confirmed that the sol-gel process utilized in this study is capable of development of homogenous distribution of yttria in the synthesized powder and stabilization of tetragonal phase at higher temperature of calcinations.
