Which element enhances corrosion resistance in stainless steel?

• A. Chromium
• B. Nickel
• C. Copper
• D. Manganese

Answer: (B)

Corrosion resistance in stainless steel comes from a protective oxide film that forms on the surface. Nickel helps this resistance by stabilizing the austenitic structure, which tends to be more resistant to corrosion and to forming problematic phases. That stable, austenitic matrix supports a uniform, adherent passive film, helping the alloy resist corrosion over a wider range of temperatures and in chloride-containing environments. In many stainless steels, especially the austenitic types, nickel works with chromium to deliver strong corrosion resistance, formability, and resistance to stress corrosion cracking. So, adding nickel enhances the overall corrosion resistance by promoting a robust passive layer and a tougher microstructure.