SUPERCRITICAL ANTISOLVENT PRECIPITATION OF NANOPARTICLES OF SUPERCONDUCTOR PRECURSORS

Supercritical antisolvent precipitation (SAS) is based on the fast dis solution of a liquid solution in a supercritical fluid. This technique has been tested to produce nanoparticles of yttrium, samarium, and ne odymium acetates to be used as precursors of high-temperature supercon ductors. Particles of various morphologies were produced at different expansion levels of the liquid solution. Nanoparticles down to about 1 00 nm were obtained at very large expansion levels, whereas very large aggregates (balloons) with the diameter of several microns were produ ced at intermediate expansion levels. The influence of several process parameters on particle diameter and particle size distribution was st udied. Among SAS process parameters, pressure, temperature, concentrat ion of the liquid solution, and different liquid solvents were tested.