Uses of Metals — Property-Use Links
Every use of a metal is justified by one or more specific properties. Always state the property AND explain how it makes the metal suitable.
| Metal/Alloy | Key properties | Uses |
|---|---|---|
| Iron | Hard, dense, strong, cheap | Construction (reinforced concrete), machinery, pipes |
| Steel | Stronger than iron, hard, magnetic | Cars, buildings, ships, tools, bridges |
| Stainless steel (Fe+Cr+Ni) | Resistant to corrosion, strong | Cutlery, surgical instruments, kitchen equipment |
| Copper | Excellent electrical conductor, ductile, good thermal conductor | Electrical wiring, water pipes, heat exchangers |
| Aluminium | Low density, resistant to corrosion (Al₂O₃ layer), malleable, ductile | Aircraft, car bodies, drink cans, cooking foil, overhead power cables |
| Titanium | High strength-to-weight ratio, resistant to corrosion, biocompatible | Jet engine parts, hip/bone implants, racing bikes |
| Brass (Cu+Zn) | Harder than copper, corrosion-resistant, attractive | Musical instruments (e.g. trumpets), door fittings |
| Bronze (Cu+Sn) | Hard, strong, corrosion-resistant | Statues, bearings, coins |
| Gold | Unreactive, malleable, excellent conductor | Jewellery, electrical contacts in electronics |
Why aluminium resists corrosion: A thin layer of Al₂O₃ forms on the surface — this is self-protective (unlike rust on iron, which flakes off and exposes more iron).
Why aluminium is used for aircraft: Low density = lightweight → less fuel needed. Resists corrosion even in rain and altitude conditions.
- Copper: best electrical conductor → wiring. Aluminium: lightweight, corrosion resistant → aircraft/cans.
- Steel: stronger than iron (C disrupts lattice) → construction, vehicles.
- Gold: unreactive, malleable → jewellery and reliable electrical contacts.