Why is nickel important in stainless steel?

In stainless steel, nickel serves several critical functions that enhance the material's performance and durability:

• Corrosion Resistance: Nickel improves the stability of the protective oxide film that forms on the surface of the steel, which is essential for resisting corrosion in various environments.1
• Austenitic Structure: Its primary contribution, particularly when used alongside chromium, is enabling the retention of an austenitic crystal structure at room temperature. This structure is characteristic of the most common and corrosion-resistant grades of stainless steel, such as the 18/8 (or 304) grade.123
• Mechanical Properties: Nickel helps provide a combination of high strength and resistance to staining and corrosion. It also allows these alloys to withstand a wide range of temperatures, making them suitable for demanding applications in the chemical, petrochemical, and power industries, as well as in jet aircraft engines.415

Because of these properties, the production of stainless steel remains the largest single industrial use for nickel.4