Nickel and Copper compounds

I placed a piece of nickel metal from a spark plug in a moderately concentrated copper(II) sulfate solution and let it sit overnight. No reaction was observed in the morning.

I then placed the nickel in some water and added a copper(II) chloride crystal. It dissolved, leaving a highly concentrated layer of copper(II) chloride solution on the bottom of the vial. The nickel metal was right in this solution. It seemed that a tiny amount of copper was produced, but even if a reaction was occurring, it was so slow that it would take weeks to get any significant amount of copper from the nickel reaction. Even placement in a boiling water bath did not produce any reaction between the copper(II) chloride and the nickel metal.

Nickel is quite an inert metal, with an oxide coating protecting against oxidation to a significant extent. It seems that this oxide coating is quite resistant to copper compounds.