Which statement best describes the effect of Nickel in steel?

• A. Increases electrical conductivity
• B. Nickel enhances the corrosion resistance in stainless steel
• C. Decreases ductility
• D. Reduces corrosion resistance

Answer: (B)

Nickel is added to steel mainly to improve corrosion resistance, especially in stainless grades. It stabilizes the austenitic (face-centered cubic) structure, which supports the formation of a uniform, protective chromium oxide film on the surface. This passive layer is self-healing and resists attack in harsh environments, including high-temperature water and chloride-containing conditions common in nuclear plant contexts. Because of that stabilizing effect and the enhanced passive film, nickel significantly boosts corrosion resistance in stainless steel, making this description the best fit.

Electrical conductivity is not the primary reason nickel is added; stainless steels with nickel typically conduct less than pure metals due to alloying. Nickel also tends to improve, not reduce, ductility and toughness, so statements about decreasing ductility or reducing corrosion resistance don’t align with nickel’s well-known benefits in stainless steel.