Abstract No.:	884
Scheduled at:	Wednesday, June 20, 2007, Brüssel 9:20 AM Fügen von Glas, Keramik und Metall Joining of glass, ceramics, metals
Title:	Reactive brazing: The effect of Ti concentration in CuAg-Ti alloys on the microstructure and performances of metal/ alumina joints
Authors:	Olga Kozlova* / SIMAP (Science et Ingénierie des Matériaux et Procédés), INPGrenoble-CNRS-UJF , France Olga Kozlova / SIMAP, INPGrenoble-CNRS-UJF, France Rayisa Voytovych/ SIMAP, INPGrenoble-CNRS-UJF, France Marie-Françoise Devismes/ Schneider Electric, France Muriel Braccini/ SIMAP, INPGrenoble-CNRS-UJF, France Nitin Shah/ A. Handy & Harmann Co. (Protechno, Lucas-Milhaupt Inc), USA Nicolas Eustathopoulos/ SIMAP, INPGrenoble-CNRS-UJF, France
Abstract:	The standard industrial process to braze alumina to itself or to metallic solids involves Mo-Mn metallization and subsequent Ni plating of alumina surfaces prior to brazing. As this technique is complex and expensive, attempts are being made to eliminate the metallization step by using brazes containing ?active? alloying elements, such as Ti. These elements react with the surfaces of alumina, and of many other ceramics, to change in situ the interfacial chemistry thus modifying the physicochemical (wetting) and mechanical (adhesion) properties of the joint. The purpose of the presentation is to describe and to discuss the fundamental issues involved in reactive brazing of alumina to alumina or of alumina to metallic solids by CuAg-Ti alloys. Ti is brought to the system either as alloying element contained in the CuAg braze or deposited by serigraphy on the alumina surface prior to brazing. Particular attention is paid to describe the effects of Ti concentration in the braze (from 1 wt.% to 10 wt.%) on the interfacial chemistry and on the type and ratio of the phases formed inside the joint. Finally, results on the mechanical performances of metal/alumina joints processed by reactive brazing will be presented and compared with data obtained by the standard method involving alumina metallization followed by bonding with normal CuAg brazes.

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