From an online description, I think the 100-lire coin is made from Cu-Ni coinage alloy of around 70% Cu / 30% Ni. The ferritic stainless steel alloy composition is unknown but would typically be at least 82% Fe (430 Alloy).
Now I see why you mentioned Cu-Ni. It looks like the one you linked was a newer series.
This is the coin I used, quoted from the same website to be composed of stainless steel:
https://www.leftovercurrency.c…-coin-minerva-large-type/
EDIT: I probably wouldn't have used the other coin type because it would have not been as large as I needed and I wanted to have mainly Fe-Cr-K oxides at the coin interface without involving significant amounts of other elements.