Influence of Mn-for-Fe substitution on structural properties of synthetic goethite

Autor: J. A. Mejía Gómez, V.G. de Resende, J. Antonissen, E. De Grave
Rok vydání: 2009
Předmět:
Zdroj: Hyperfine Interactions. 189:143-149
ISSN: 1572-9540
0304-3843
Popis: In order to study the effect of alloying elements, such as manganese, on the properties of the rust on weathering steels, a series of Mn-goethite samples containing different amounts of Mn were synthesized from ferrihydrite in alkaline media. The samples were characterized by X-ray diffraction (XRD) and Mossbauer spectroscopy. The cell parameters calculated from the XRD patterns showed clearly that the a- and c-parameters decrease while the b-parameter increases with increasing Mn concentration, indicating that the octahedra of the goethite structure become distorted by an incorporation of Mn (Jahn–Teller-effect). Mossbauer spectra of the samples were recorded at room temperature (RT) and at 80 K. The quadrupole shift values gradually decrease with increasing Mn substitution in the goethite structure. It has been observed that the magnetic hyperfine field values of maximum probability are reduced with increasing Mn in the samples. No doublet component was observed in the RT MS spectra suggesting that no effects of superparamagnetim resulting from smaller particles are present.
Databáze: OpenAIRE