During the sintering operation of electrical cable having Teflon taped, silver plated copper wires, the silver plating gets a yellowish (sometimes even a rainbow) color layer, which can be rubbed off by hand. How do we avoid this yellowing of the silver plating? Can anybody guide me please?

Singhal

Could be a problem of "Red Plaque" which has been a problem for over 40 years and is related to silver plate thickness and consistency and water ingress causing corrosion at point where copper is exposed. Many papers over the years but main cure from what I have seen is very tight quality control on silver plating process.


Erik Macs
Fine International Corp.
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Further to Mr. Erik Macs comment about "Red Plague", I thought the following pdf document might be of some interest.

nepp.nasa.gov/docuploads/97164203-A4FB-4...A%20Red%20Plague.pdf

It is a type or form of oxidation. The heat in the sintering process is either too high or the speed too slow. For those that are wondering the Teflon tape or film is wrapped around the conductor in a fashion that there is a certain amount of overlapping. When the wire is run through an oven or heating system the layers of Teflon will bond with each other and this is called sintering.