=== 4.1 Brazing Alloys ===

For the joining of contact materials with carrier substrates brazing alloys with working temperatures > 600 °C are used exclusively. The working temperature is defined as the lowest surface temperature by which the brazing material wets the materials to be joined. This temperature is within the melting range and between the solidus (temperature at which melting starts) and liquidus (temperature at complete liquid state) point of the brazing alloy. Silver-based brazing alloys have good electrical conductivity and a sufficient mechanical

strength which allows a bonding process without significant changes in the 4

For the brazing of contacts with a silver bottom layer to copper backings phosphorous containing brazing alloys which eliminate the need for a flux application are widely used.

The brazing alloy is typically introduced into the joint area in the form of wire segments, foil, shims, or as powder or paste. For larger production volumes it is economically advantageous to pre-coat contact tips with a thin layer (< 100 µm) of brazing alloy.

=== 4.2 Fluxes ===

Brazing fluxes consist of non-metallic materials, mostly salt mixtures of boron and halogen compounds ''(Table 4.2)''. Their purpose is to remove oxides from