- aman bhati
Why copper gets brittle after nickel coating?
I would say that the problem is simple. It is called contamination.
You want metallic Nickel and copper but if you put sulphides together with Ni and Cu, they react to form CuS and NiS, very insoluble salts. They will grow up as salt crystals forming salt layers, lines, spots, etc, instead of allowing the metallic surface to form properly.