MCQ Detailed View

Stainless steel is an iron-based alloy that is highly resistant to corrosion and rust. Its main components are iron (Fe), chromium (Cr), and nickel (Ni). Chromium is added to stainless steel to provide corrosion resistance. When chromium content exceeds about 10.5%, a thin, stable layer of chromium oxide forms on the surface of the steel. This oxide layer prevents further oxidation and protects the metal from rusting.

Nickel is added to improve the ductility, toughness, and overall corrosion resistance of stainless steel. Nickel also stabilizes the austenitic structure in the steel, which enhances mechanical strength and ensures uniformity in microstructure. Depending on the application, stainless steel may contain small amounts of other elements such as manganese (Mn), carbon (C), or molybdenum (Mo), but Fe + Cr + Ni remains the principal composition.

Other options listed in the question are incorrect. Fe + Ni + Cu or Fe + Cr + Cu are not standard stainless steel compositions. Copper is not commonly used in stainless steel, as it does not provide significant corrosion resistance. Cu + C + Ni is unrelated to stainless steel composition.

Stainless steel is widely used in kitchen utensils, surgical instruments, chemical tanks, architectural structures, and pipelines due to its durability and resistance to oxidation. Its ability to resist corrosion makes it suitable for both domestic and industrial applications.

Understanding the composition of stainless steel is important in materials science, metallurgy, and inorganic chemistry, as it explains why chromium and nickel are critical elements for producing a corrosion-resistant and mechanically strong alloy.