Core-shell materials elaboration in supercritical mixture CO2/ethanol

Supercritical fluids exhibit a range of unusual properties that can be expl oited for developing new processes. In this paper a new way for particle co ating is presented. It consists of depositing on a core particle a thin lay er of a material based on copper in a supercritical medium. Two examples ar e described: a deposit of Cu on nickel particles and a deposit of Cu on par ticles of permanent magnet SmCo5. In both cases the copper source is bis(he xafluoroacetylacetonate)copper(II), which is thermally decomposed in the su percritical mixture CO2/ethanol. This process allows one to obtain new "cor e-shell structures", Ni/Cu and SmCo5/Cu. New interesting properties are exp ected for these structures, more particularly in the magnetic recording fie ld.