Changes

==7.6 Passivation of Silver Surfaces==

The formation of silver sulfide during the shelf life of components with silver surface in sulfur containing environments can be significantly eliminated by coating them with an additional protective film layer (Passivation layer). For electrical contact use such thin layers should be chemically inert and sufficiently conductive, or be easily broken by the applied contact force.

The passivation process SILVERBRITE W ATPS is a water-based tarnish preventer for silver. It is free of chromium(VI) compounds and solvents. The passivating layer is applied by immersion which creates a transparent organic protective film which barely changes the appearance and only slightly

increases the good electrical properties such as for example the contact resistance. The good solderability and bond properties of silver are not

Fig. 7.7: Typical process flow for the SILVERBRITE W ATPS process

==References==