Non-Ferrous Metals & Alloys

This lesson covers non-ferrous metals (metals that do NOT contain iron) and their alloys (mixtures of two or more metals). These are essential materials in AQA GCSE Design and Technology (8552), Section 3.1.6.

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What Are Non-Ferrous Metals?

Non-ferrous metals do not contain iron. This gives them two key advantages over ferrous metals:

1. They do not rust (though some may corrode in other ways).
2. They are not magnetic.

graph TD
  ME[Metals]
  ME --> FE["Ferrous<br/>contain iron, rust, magnetic"]
  ME --> NF["Non-Ferrous<br/>no iron, no rust, non-magnetic"]
  NF --> P[Pure Metals]
  NF --> AL[Alloys]
  P --> P1[Aluminium — light, anti-corrosion]
  P --> P2[Copper — electrical conductor]
  P --> P3[Tin — corrosion resistant coating]
  P --> P4[Zinc — galvanising layer]
  P --> P5[Silver — best conductor, jewellery]
  AL --> A1[Brass — Cu + Zn — taps, fittings]
  AL --> A2[Bronze — Cu + Sn — bearings, sculptures]
  AL --> A3[Pewter — Sn + Cu/Sb — tankards, casting]
  AL --> A4[Duralumin — Al + Cu/Mg — aircraft]

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Pure Non-Ferrous Metals

Aluminium

Property	Detail
Colour	Silver-white
Density	Very low — about one-third the weight of steel
Corrosion resistance	Excellent — forms a protective aluminium oxide layer
Conductivity	Good electrical and thermal conductor
Malleability	Excellent — easily pressed, rolled and formed
Strength	Low when pure; much stronger as an alloy
Machinability	Easy to cut and machine
Recyclability	100% recyclable; recycling uses only 5% of the energy of primary production

Uses: Drinks cans, kitchen foil, aircraft structures (as alloy), window frames, bicycle frames, cooking pots, electrical cables (overhead power lines).

Copper

Property	Detail
Colour	Distinctive reddish-orange; develops green patina (verdigris) over time
Conductivity	Best electrical conductor after silver; excellent thermal conductor
Malleability	Very malleable — easily formed into tubes, sheets and wire
Ductility	Very ductile — drawn into thin wire
Corrosion resistance	Good — tarnishes but does not rust
Antimicrobial	Naturally kills bacteria on contact
Cost	Moderately expensive

Uses: Electrical wiring, plumbing pipes and fittings, PCB tracks, roofing, decorative items, cookware bases, coins (as alloy).

Silver

Property	Detail
Colour	Bright, lustrous white
Conductivity	Highest electrical and thermal conductivity of any metal
Malleability	Excellent
Corrosion	Tarnishes (blackens) when exposed to sulphur compounds in air
Cost	Expensive (precious metal)

Uses: Jewellery, silverware, electronics (contacts, solder), photography (historically), antibacterial coatings.

AQA Exam Tip: You do not need to memorise every property of every metal, but you should know at least two key properties and two applications for each. Link properties to uses — e.g. copper's excellent conductivity makes it ideal for electrical wiring.

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Alloys

An alloy is a mixture of two or more metals (or a metal and a non-metal) to produce a material with improved properties compared to the individual metals.

Why Make Alloys?

Reason	Example
Increase strength	Pure aluminium is soft; adding copper, magnesium, etc. creates duralumin, which is much stronger
Increase hardness	Pure copper is soft; adding zinc creates brass, which is harder
Improve corrosion resistance	Adding chromium to iron creates stainless steel
Change colour / appearance	Adding zinc to copper changes the colour from red to gold (brass)
Lower melting point	Solder (tin + lead/other metals) melts at low temperatures for joining
Improve castability	Some alloys flow better when molten, filling moulds more completely

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Common Non-Ferrous Alloys

Brass

Property	Detail
Composition	Copper (~65%) + Zinc (~35%)
Colour	Gold/yellow
Hardness	Harder than pure copper
Machinability	Excellent — machines to a fine finish
Corrosion resistance	Good — does not rust; resists tarnishing
Conductivity	Good (but lower than pure copper)
Cast quality	Good — fills moulds well

Uses: Door handles, hinges, locks, musical instruments (trumpets, trombones), plumbing fittings, decorative items, electrical connectors, gears and bearings.

Duralumin

Property	Detail
Composition	Aluminium (~94%) + Copper (~4%) + Magnesium (~1%) + Manganese (~1%)
Strength	Much stronger than pure aluminium — comparable to mild steel
Weight	Still very lightweight (similar to aluminium)
Corrosion	Less resistant than pure aluminium — often clad with pure aluminium (Alclad)
Machinability	Good

Uses: Aircraft structures, bicycle frames, lightweight structural components, automotive parts.

Pewter

Property	Detail
Composition	Tin (~91%) + Antimony (~7%) + Copper (~2%)
Colour	Silvery-grey with a warm lustre
Melting point	Low (~230 °C) — easy to cast
Hardness	Soft
Malleability	Very malleable
Corrosion	Excellent resistance; does not tarnish easily
Toxicity	Modern pewter is lead-free and food-safe

Uses: Decorative items (tankards, goblets, plates, figurines), jewellery, trophies, hip flasks, school D&T casting projects.

AQA Exam Tip: Pewter is the most commonly cast alloy in school D&T workshops because of its low melting point (~230 °C), making it safe for casting with simple equipment. This is a frequently tested practical context.

Bronze

Property	Detail
Composition	Copper (~88%) + Tin (~12%)
Hardness	Hard and strong
Corrosion	Excellent — used in marine environments
Casting	Excellent castability
Sound	Produces a distinctive ringing tone

Uses: Sculptures, statues, bells, bearings, ship propellers, medals and coins.

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Comparing Non-Ferrous Metals and Alloys

Metal/Alloy	Key Property	Key Application	Magnetic?	Rusts?
Aluminium	Lightweight, corrosion-resistant	Drinks cans, aircraft (as alloy)	No	No
Copper	Best conductor (after silver)	Electrical wiring, plumbing	No	No (tarnishes)
Silver	Highest conductivity of all metals	Jewellery, electronics	No	No (tarnishes)
Brass	Hard, gold colour, machines well	Door handles, instruments	No	No
Duralumin	Strong AND lightweight	Aircraft, bicycle frames	No	Poor (needs Alclad)
Pewter	Low melting point, easy to cast	Decorative items, school casting	No	No
Bronze	Hard, corrosion-resistant, castable	Sculptures, bells, bearings	No	No

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Recycling Non-Ferrous Metals

Metal	Recycling Notes
Aluminium	Infinitely recyclable; recycling saves 95% of the energy of primary production; widely collected (cans)
Copper	Infinitely recyclable; valuable scrap metal; plumbing and electrical waste
Brass	Easily recycled; separated magnetically from ferrous metals (brass is non-magnetic)

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Summary