ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
A combustion-synthesis method1 has been adapted2 for the preparation of barium ferrite. In this method, stoichiometric amounts of metal-nitrate solutions are mixed and glycine (aminoacetic acid) is added at specific glycine/metal-nitrate ratios. The resulting solution is then heated until autoignition (combustion). The combustion products for several G/N ratios have been analyzed by XRD, Mössbauer spectroscopy, and EDS; they consist of hematite and/or maghemite with traces of residual barium nitrate that vary according to the G/N ratio. Packing experiments reveal a dramatic variation in density of the powdered combustion products ranging from 0.08 to 0.87 g/cm3 for G/N=0.4 to 0.7 molar, respectively. SEM micrographs show what appear to be sintered ceramic flakes of undetermined particle shape. Barium ferrite is obtained with subsequent heat treatment. Along with TEM, SSA, and VSM analysis of the combustion products and the converted barium ferrite, a DTA determination of minimum phase-change temperature from γ-Fe2O3, Ba(NO3)2, and α-Fe2O3 to barium ferrite for specific G/N ratios will be given. Using these data, we will discuss optimum conditions for the preparation of pure barium ferrite with this combustion method, according to the physical and magnetic properties desired for the final product.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.352519
