engleski

Mössbauer spectroscopy and X-ray diffraction of oxide precipitates formed from FeSO4 solution

Chemical and structural properties of oxide precipitates formed from FeSO4 solution were investigated using X-ray diffraction and57Fe Mössbauer spectroscopy. The hydrolysis of urea at elevated temperature was used for the generation of OH- ions during the precipitation process. The formation of particular oxide phase in the precipitate is strongly dependent on the concentrations of FeSO4 and urea, as well as on the rate of oxygenation. The phase analysis of precipitates showed the presence of different oxide phases, such as goethite, lepidocrocite, hematite and magnetite, and in one sample of a small amount of siderite. Only substoichiometric magnetite, Fe3-xO4, was detected. Significant differences in the Mössbauer spectrum of goethite were observed, due to a very small particle size, the degree of crystallinity and/or different content of structurally bonded water. The correlation between the Mössbauer spectra of precipitated goethite and goethite formed during the atmospheric corrosion of steel is discussed.

goethite ; lepidocrocite ; hematite ; magnetite ; 57Fe Mössbauer spectroscopy ; X-ray Diffraction ; Oxygenation Rate ; Iron and Steel Metallography--Precipitation ; Steel Corrosion--Atmospheric ; Urea

nije evidentirano