Preparation of Ultrafine Cobalt Ferrite Particles by Solution SHS Method
Nanosized CoFe2O4 powders of 12nm particle size were directly prepared by solution SHS method at room temperature. The overall process involves three steps: formation of homogeneous sol; formatiom of dried gel; and combustion of the dried gel. Experiments revealed that CoFe2O4 dried gel derived from citrate and nitrate sol exhibited self-propagation combustion(SHS) at room temperature once it was ignited in air. After self-propagating combustion, the gel directly transforms into nanosized CoFe2O4 particles. The self-propagating combustion was considered as a heat-induced exothermic oxidation-reduction reaction between nitrate ions and carboxyl group. Differential thermal analysis-thermogravimetry (DTA-TG) was used to study the decomposition of the precursor. The structure of the nanosized CoFe2O4 powders was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM).
Xiaoming Sang, Pengcheng Wang, Liqun Ai, Yungang Li and Jinglong Bu
X. E. Li and X. H. Zhu, "Preparation of Ultrafine Cobalt Ferrite Particles by Solution SHS Method", Advanced Materials Research, Vols. 284-286, pp. 645-648, 2011