Summary for stripping nickel from kovar Discussion
Nickel stripping from Kovar is tricky because the substrate itself is a nickel-rich, cobalt-rich alloy, so the stripper may attack both the deposit and the base metal. The thread explains that stripping is usually easy when the coating and substrate are very different, but much harder when they are similar. In this case, the customer wants nickel removed from nickel-plated Kovar shields without etching the Kovar underneath. The practical takeaway is that a selective stripper may not be straightforward, and the process must be chosen carefully to avoid damaging the substrate. The excerpt does not include a final recommended chemistry or procedure, only the warning that similar metals are difficult to separate cleanly.
Stripping solutions are not mind readers. When the plating and the substrate are very similar materials, the stripper doesn’t “know” what you want stripped and don’t want stripped, so it becomes more difficult.
Kovar is a nickel-rich, cobalt-rich, alloy often used in glass to metal seals because it is both corrosion resistant and offers a thermal expansion coefficient similar to glass.
Q. We’ve nickel plated some Kovar shields that for whatever reason the customer wants stripped. As Kovar is a high nickel rich alloy, what’s the best approach for removing the nickel without etching the Kovar substrate?
Milt Stevenson, Jr.
Plating shop technical manager – Syracuse, New York
July 24, 2025