MECHANOCHEMICAL SYNTHESIS OF ULTRAFINE ZRO2 POWDER

The synthesis of ultrafine zirconia powders by mechanochemical reactio n of ZrCl4 with CaO has been investigated using x-ray diffraction, TEM and DSC measurements. Mechanical milling resulted in a nanoscale mixt ure of CaO and amorphous ZrCl4, with no evidence of any reaction havin g occurred. Subsequent heat treatment at temperatures above 300 degree s C resulted in the formation of separated particles of cubic ZrO2, 5- 10 nm in diameter, within an CaCl2 matrix. Measurements of the effect of particle size on the crystal structure of ZrO2 are also reported.