Bronze
- Cu + (Tin) Sn.
- harder than copper. more fusible.
- harder than pure iron and far more resistant to corrosion. (The substitution of iron for bronze in tools and weapons from about 1000 bc was the result of iron’s abundance compared to copper and tin rather than any inherent advantages of iron.)
Bell metal
- sonorous quality when struck, is a bronze with a high tin content of 20–25 percent.
Brass
- alloy of copper and zinc
- To enhance the machinability (‘free turning’) of brass, lead is often added in concentrations of around 2%.
alpha brasses
- Malleable brasses
- can be worked cold (generally those with less than 40 percent zinc)
beta brasses
- less ductile but stronger
- suitable for the manufacture of faucet handles, sprinkler heads, window and door fittings, and other fixtures.
White brass
- more than 45 percent zinc are not workable, either hot or cold. Such brasses, known as white brasses, are of little industrial importance.
Further mixtures
lead brasses
- more easily machined
- Statuary bronze, with a tin content of less than 10 percent and an admixture of zinc and lead, is technically a brass.
naval and admiralty brasses
- a small amount of tin improves resistance to corrosion by seawater
aluminum brasses
- provide strength and corrosion resistance where the naval brasses may fail.
Lead poisoning
Lead is still added to brass and bronze used to make drinking water faucets and food equipment
Brass
Musical instruments
Lead can be absorbed by prolonged contact with raw brass. In the past it was thought that the plating on brass mouthpieces offered complete protection from the lead in the mouthpiece, but tests have shown that very small quantities of lead can migrate through the plating over time.
Keys
Locksmiths had significantly higher current exposure to lead (blood lead concentration)