Kinetik der Sigma - Phasen - Ausscheidung in Fe - Cr - Legierungen für Interkonnektoren in SOFC - Brennstoffzellen

Translated title of the contribution: Characterization of sigma-phase precipitation in Fe - Cr - alloys for interconnects in solid oxide fuel cells

Manuel Prohaska

Research output: ThesisDiploma Thesis

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Abstract

Fuel cells offer the possibility of zero-emission electricity generation. Fuel cell materials exhibit exceptional properties, especially high-temperature strength and corrosion resistance. Nowadays iron-based alloys with high chromium content are used as structural materials in fuel cells. These materials could precipitate an intermetallic phase type, called sigma-phase, during service, which has negative influence on the material properties. In this thesis, three different alloys of the company Plansee SE were investigated and the volume fraction of the precipitated sigma-phase and its chemical composition was determined. Furthermore, the influence of the microstructure on the formation and kinetics of sigma-phase precipitation was investigated by means of Differential Scanning Calorimetry (DSC), dilatometry and optical microscopy. X-ray-Diffraction (XRD) was used to determine the crystal structure and the lattice parameters. The nanostructure of the investigated materials was imaged by means of 3DAP. Differences between the Plansee materials with respect to grain structure and nanostructure were determined and the influence of the chemical composition on the volume fraction of precipitated sigma-phase was examined. In addition, the influence of the processing parameters on sigma-phase precipitation was investigated. Finally, the materials provided by Plansee were compared with a material of a competitor (Crofer22APU).
Translated title of the contributionCharacterization of sigma-phase precipitation in Fe - Cr - alloys for interconnects in solid oxide fuel cells
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Clemens, Helmut, Supervisor (internal)
  • Leitner, Harald, Co-Supervisor (internal)
  • Kunschert, Georg, Co-Supervisor (external), External person
Award date27 Jun 2008
Publication statusPublished - 2008

Bibliographical note

embargoed until null

Keywords

  • fuel cells sigma-phase nucleation mechanisms precipitation kinetics DSC XRD dilatometry 3DAP

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