SmCo5/Cu particles elaboration using a supercritical fluid process

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