"Stainless steel as a substrate to plate onto"

Plating can only successfully and robustly build onto a clean raw metal base, not onto an oxidized surface, but stainless steel is an active metal which oxidizes almost instantaneously.

Thus, plating onto stainless steel is usually done by starting with a Wood's Nickel Strike or other strike solution, which is highly acidic and low in metal such that it can dissolve the oxides on the stainless while simultaneously depositing a very thin layer of nickel.

Please search the site for "Wood's Nickel".