There are varying grades of stainless steel depending on the amount of nickel and chromium added. Better stainless steels also contain nickel as well as chromium.
Nickel gives the stainless better ductility and formability but adds to the cost.
Corrosion Resistance Addition of nickel and chromium to iron produces an alloy called stainless steel that is very resistant to corrosion. Copper and copper alloys are also very corrosion resistant. Aluminum is also very corrosion resistant.