Chloride Residue Can Attack Copper Exposed by Plating Blisters

What the evidence preview establishes

Residual chloride from assembly flux was the primary corrosion driver. Blistering at the nickel-to-copper interface provided rupture sites that exposed the copper base alloy, creating local sources for copper-rich corrosion products.

Why this case matters

Do not infer inadequate plating thickness solely from substrate elements in a surface spectrum. Section the finish, inspect for interfacial blistering, map exposed base metal, and control ionic cleanliness after assembly.