ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The brazing of commercially pure titanium to Al2O3 has been studied. Two different brazing alloys within the Ag–Cu–Ti system and pure silver were selected as bonding agents. Titanium hydride (TiH2) additions were also tested, with the aim of improving the wetting of the ceramic surface by the melted brazing alloy. The mechanical and electrochemical behaviour of the produced joints was assessed, and related to chemical and morphological features resulting from an analysis by scanning electron microscopy and energy dispersive spectroscopy. It was possible to produce joints presenting high integrity, good strength and high resistance to corrosion. The best results were obtained when using an Ag–26Cu–3Ti brazing alloy. The addition of TiH2 increased the mechanical properties, leading to a maximum bonding strength of 80±8 MPa, as determined in three-point bending tests. In most of the cases, for a maximum deflection of 5 mm, there was only a partial detachment of the ceramic/metal joints. The lowest values for the corrosion rates (icorr=1.38 μA cm−2) determined in potentiodynamic experiments also correspond to the use of the Ag–26Cu–3Ti brazing alloy. The bonding strength and electrochemical results could be explained in terms of the different chemical compositions of the interfaces. The use of TiH2 additions proved to be quite effective, allowing for the replacement of the usual metallizing and plating pre-treatments needed for the brazing of ceramics to metals.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1018531617529
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