- AutorIn
- Flaurance Kenfack
- Titel
- Complex oxides of the system Cu-Ni-Fe-O: synthesis parameters, phase formation and properties
- Zitierfähige Url:
- https://nbn-resolving.org/urn:nbn:de:swb:14-1105366432765-06401
- Übersetzter Titel (DE)
- Komplexe Oxide des Systems Cu-Ni-Fe-O: Syntheseparameter, Phasenbildung und Eigenschaften
- Datum der Einreichung
- 14.10.2004
- Datum der Verteidigung
- 15.12.2004
- Abstract (EN)
- This thesis describes the convenient routes and the preparation conditions (temperature, oxygen partial presssure) which lead to the formation of single phase materials within the quaternary system Cu-Ni-Fe-O. The investigated compositions are the solid solutions CuxNi1-xFe2O4, the ferrites occurring in the phase triangle Cu0.5Ni0.5Fe2O4 -Cu0.9Fe2.1O4 - Cu0.5Fe2.5O4 and some copper-nickel oxide solid solutions. Three synthesis routes have been used, namely (i) the preparation and the thermal decomposition of freeze-dried carboxylate precursors, (ii) the preparation and the oxidation of intermetallic phases and (iii) the preparation and the heat treatment in air of mixed oxide/metallic powders. The thermal decomposition of freeze-dried Cu-Ni-Fe formate has been found as a suitable method for preparing single spinel phases within the Cu-Ni-Fe-O system. In comparison with the conventional solid state reaction, the required temperature is much lower. Concerning the solid solution CuxNi1-xFe2O4 , a single phase spinel is formed at 1000¢XC for x < 0.7; for CuO is identified as second phase. In this latter range the formation of a pure phase required an increase of the iron content in the mixture. The other single spinel phases in the phase triangle Cu0.5Ni0.5Fe2O4 - Cu0.9Fe2.1O4 - Cu0.5Fe2.5O4 have been synthesized under special synthesis p(O2)/T-conditions. For copper ferrites Cu1-xFe2+xO4 with x ? 0.1, 0.2, 0.33, 0.4 and 0.5, the change in the conductivity with the temperature is irreversible. The deviation from the linearity of the conductivity ?ã as a function of the temperature occurs due to the thermal history of these samples. The saturation magnetic moment (nB) at 5K, of some synthesized CuxNi1-xFe2O4 compounds has been determined. It has been found that nB increases with the nickel content in the ferrite sample.
- Freie Schlagwörter (DE)
- Kupferferrit, Sauerstoffstöchiometrie,Nickelferrit, Gefriergetrocknung,Oxalate, Formiate
- Freie Schlagwörter (EN)
- copper ferrite, oxygen stoichiometry, nickel ferrite, freeze-drying, oxalate, formate
- Klassifikation (DDC)
- 530
- Klassifikation (RVK)
- VE 9507
- Normschlagwörter (GND)
- Ferrite, Formiate, Kupfer, Nickel, Oxalate, Phasendiagramm, Quaternäres System
- GutachterIn
- Pr. Dr. Hubert Langbein
- Pr. Dr. Helmut Ullmann
- Pr.Dr. Gerhard Roewer
- BetreuerIn
- Pr. Dr. Hubert Langbein
- Verlag
- Technische Universität Dresden, Dresden
- URN Qucosa
- urn:nbn:de:swb:14-1105366432765-06401
- Veröffentlichungsdatum Qucosa
- 12.12.2004
- Dokumenttyp
- Dissertation
- Sprache des Dokumentes
- Englisch
- Lizenz / Rechtehinweis