Thermomagnetic study of surface cobalt modified iron oxide particles derived from oxalic precursors

The cobalt modification of pure gamma -Fe/sub 2/O/sub 3/ acicular particles by the so-called epitaxial process has been applied to gamma -Fe/sub 2/O/sub 3/ particles, derived from oxalic precursors. Six elaboration parameters have been taken into account for the slurry heat treatment: cable content, pH, time, temperature, gas flowing into the solution, and surface activation. A thermomagnetic study including in situ annealing treatments and magnetic measurements at various temperatures in the range 20-380 degrees C has been carried out. The results are compared with those of commercial surface-cobalt-modified pigments.<
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