Dresden 2006 – wissenschaftliches Programm

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MM: Metall- und Materialphysik

MM 27: Diffusion I

MM 27.3: Vortrag

Donnerstag, 30. März 2006, 10:45–11:00, IFW B

Nonisothermal Internal Oxidation of Iron in Palladium — •Jürgen Gegner — SKF GmbH, Material Physics, Ernst-Sachs-Str. 5, D-97424 Schweinfurt, Germany

Incomplete isothermal-isobaric internal oxidation of dilute homogeneous alloys is a frequently used experimental technique to measure the diffusion coefficient of oxygen in the base metal. Adopting this method, however, derivation of the Arrhenius equation requires a series of anneals at different temperatures. In the present work, a recently introduced [1], simplified experimental procedure is applied to the binary Pd-Fe system: incomplete temperature-controlled isobaric internal oxidation. Mathematical evaluation of the time development of the subscale thickness, which follows from SEM micrographs of samples that are removed from the furnace at several durations of the air annealing, is performed by means of an iterative computer model [2]. In this realistic process simulation, the sought quantity, i.e. the diffusivity D_O of oxygen in palladium, is the fit parameter and found to be:

Here, D_O is expressed in cm²/s and temperature T ranges from 1073 to 1473 K. This result is compared with literature references.

[1] J. Gegner: Komplexe Diffusionsprozesse in Metallen. expert-Verlag, Renningen (2006), p. 397-402

[2] J. Gegner: New Computer Model for Internal Oxidation. Proc. MMT-2004, p. 1/28-1/37