Alloys

Definition

A solid mixture (or solution) of two or more elements, at least one of which is a metal, made to obtain properties better than those of the pure metals.

Key points

• Alloying improves strength, hardness, corrosion resistance, or appearance; for example pure iron is soft, but steel (iron with carbon) is hard and strong.
• Common alloys: steel (iron + carbon), stainless steel (iron + chromium + nickel, rust-resistant), brass (copper + zinc), bronze (copper + tin), and solder (tin + lead).
• Duralumin (aluminium + copper + magnesium + manganese) is light and strong and is used in aircraft; amalgam is an alloy in which one metal is mercury.
• Alloys generally have a lower melting point and lower electrical conductivity than their pure components; this is why solder melts easily for joining circuits.
• German silver (copper + zinc + nickel) contains no silver, despite its name.

Why it matters for CAPF

The composition and uses of common alloys (steel, stainless steel, brass, bronze, solder, duralumin) are frequently asked materials-chemistry facts, and high-strength alloys matter for defence equipment.

Common confusion

German silver and solder contain no silver and no actual change of element; they are simply mixtures. Brass is copper and zinc, while bronze is copper and tin; these are commonly mixed up. Steel is an alloy of iron with a small amount of carbon, not a pure metal.

Related concepts

concept catalysts, concept superconductors

Parent note

chemistry everyday