Wetting and brazing of stainless steels by copper–silver eutectic.pdf

Materials Science and Engineering A 495 (2008) 96–101 Wetting and brazing of stainless steels by copper–silver eutectic O. Kozlova a,∗, R. Voytovych a , M.-F. Devismesb , N. Eustathopoulos a a SIMaP, INPGrenoble-CNRS-UJF, BP 75, F-38402 Saint Martin d’H`eres Cedex, France b Schneider Electric, ZAC St-Ange, 4 rue de l’industrie, F-38760 Varces Alli`eres et Risset, France Received 10 April 2007; received in revised form 24 September 2007; accepted 24 October 2007 Abstract The wetting of stainless steels by Cu–Ag-based alloys was studied by the sessile drop and dispensed drop techniques in high vacuum at 800–900 ◦C. Experiments were performed by varying the steel type, composition of the Cu–Ag-based alloy and furnace atmosphere. The results were used to determine the processes controlling the wetting and brazing of these important technological materials. © 2008 Elsevier B.V. All rights reserved. Keywords: Spreading; Stainless steels; Oxide film; Interface; Brazing alloys 1. Introduction evoked to explain deoxidation: disruption of the film caused by the reaction between the brazing alloy and the steel [2,3], for- Stainless steels are covered by tenacious oxide layers, mak- mation of volatile oxides by certain components of ss [4] and ing them highly resistant to oxidation. These passive films are reduction by residual carbon [5,6]. also a barrier for wetting and brazing by liquid metals and alloys This study had a dual aim. First, to contribute to the under- [1]. However, above a certain temperature, heating in high vac-