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MM: Fachverband Metall- und Materialphysik
MM 15: Poster session I
MM 15.13: Poster
Montag, 7. März 2016, 18:00–20:00, Poster B3
Deoxidation of stainless steels during vacuum brazing — •Cornelia Kunz1, Wolfgang Maus-Friedrichs1, Simon Schöler2,3, Ulrich Holländer2,3, and Kai Möhwald2,3 — 1Clausthaler Zentrum für Materialtechnik, Technische Universität Clausthal, Germany — 2Institut für Werkstoffkunde, Bereich Füge- und Oberflächentechnik (Fortis), , Leibniz Universität Hannover, Germany — 3Institut für Werkstoffkunde, Leibniz Universität Hannover, Germany
Stainless steels are in widespread use due to their excellent mechanical and corrosion-proof properties. Corrosion resistance stems from native oxide layers formed on the surface of stainless steels, only a few nanometers thick and consisting of a mixture of chromium and iron oxides and hydroxides.
However, when choosing to join stainless steels by the means of vacuum brazing, the oxide layer prevents the wetting of the surface with braze, therefore inhibiting the joining process. Thus, deoxidation is a necessity. While procedural knowledge is abundant, fundamental understanding of thermophysical and chemical processes is lacking. Deoxidation is studied with two different stainless steels, AISI 304 and 446. Effect of heat treatment during vacuum brazing is recreated in laboratory scale by electron impact heating. Chemical analysis before and after heat treatment is carried out by XPS, AES and EDX/ WDX, optical and topographical properties are studied by CLSM. Bulk changes can be separated from surface changes due to different information depths of XPS/ AES and EDX/ WDX.