Processing and properties of composite magnetic powders containing Co nanoparticles in polymeric matrix

Polymeric matrix ferromagnetic nanocomposites, containing Co nanocrystallites were processed by an innovative fabrication method using frontal polymerisation of cobalt acrylamid complex (CoAAm), followed by further thermolysis. The products of thermolysis were in a form of irregular powder particles having broad range of size distribution, from 10 mu m up to 300 mu m. The powder particles contain nanocrystallites of Co having the mean 12-15 nm, depending on the thermolysis temperature. The particles are randomly distributed and their size and agglomeration can be controlled by the processing variables. The hysteresis loops recorded for materials processed at 873 and 1073 K, respectively proved that the coercivity depends on the processing temperature and very slightly on the measurement temperature. According to the commonly approved classification the coercivity of the composite material processed at temperatures 873 and 1073 K can be regarded as magnetically soft and hard, respectively. (c) 2006 Published by Elsevier B.V.