Cobalt nanoparticles processed by thermal decomposition of metal-containing monomers

Polymer matrix ferromagnetic nanocomposites, containing Co nanocrystallites, were processed by an innovative fabrication method that uses the frontal polymerisation of cobalt acrylamid complexes, followed by subsequent thermolysis at 873 and 1073 K. The thermolysis products were in the form of irregular powder particles, with a broad size distribution, from 10 up to 300;mu m. The powder particles contained nanocrystallites of Co with a mean size in the range 12-15 nm, depending on the thermolysis temperature. The hysteresis loops recorded for materials processed at 873 and 1073 K proved that coercivity depends on the processing temperature and very slightly on the measurement temperature. The thermolysis product, processed at 873 K, showed soft magnetic properties. The particles were randomly distributed and their size and agglomeration could be controlled by the processing variables.