SmCo5/Cu particles elaboration using a supercritical fluid process

Supercritical fluids exhibit a range of unusual properties that can be exploited for developing new processes. Thus, a new way for particles coating is presented. It consists of depositing on a core particle a thin layer of copper. The core particles are made of ground SmCo5. The evolution of the magnetic properties of SmCo5 is studied as a function of the milling time. The copper source is the copper hexafluoroacetylacetonate (Cu(hfa)(2).H2O), which is thermally decomposed in a supercritical medium. Then, the influence of the copper layer is evaluated. This process obtains new 'core-shell structures' as SmCo5/Cu. New interesting properties are expected for these structures more particularly in the magnetic recording field. (C) 2001 Elsevier Science B.V. All rights reserved.