CoFe2O4 NANOSTRUCTURED MAGNETIC MATERIALS: INFLUENCE OF NOT-CONVENTIONAL METHODS OF COMPACTION (SPS, HIP) ON THE MICROSTRUCTURE AND PHYSICAL CHARACTERISTICS.

摘要

This work presents a Bottom-Up strategy implementing methods of soft chemistry followed by processes of not conventional compaction for making of CoFe2O4 spinel nanostructured materials. The optimization of the process routes to obtain bulk and dense materials will be described in details along with the material nanostructures and magnetic properties. Initially, the nanopowders (10 nm) are obtained in solution by hydrolysis forced in polyol medium. CoFe2O4 nanoparticles have been obtained starting from ionic salts (cobalt acetate and iron chlorate) dissolved in a polyol and heated at a boiling point. The chemical reactions are made possible by several properties of polyols, including high boiling point, dissolving, complexing, hydrolysing and protective properties. This route enables to synthesize particles of size and morphology controlled. These powders prove to have interesting magnetic properties in comparison with those worked out by other ways of soft chemistry [1]: high saturation magnetization near to the bulk materials and temperature of blocking higher than the ambient one.