Bronze Age ( 2300BCE to 1000 BCE) :

Working copper was difficult (its melting point was very high for simple wood fires) and the finished products were fairly

soft.

It was discovered that heating copper and tin ores with charcoal produced a much harder metal alloy Bronze.

Bronze has a lower melting point than copper therefore could be melted, moulded and worked much more easily in wood

fires.

By 2000 BCE bronze was commonly used for tools and weapons throughout Europe and Asia.

Bronze was dominant material for tools and weapons.

By 3000 BC bronze, an alloy of copper and tin, had replaced copper and the Bronze Age had begun. Bronze may have

been first discovered accidentally when ores containing both metals were heated together. Once its advantages were

realised, people began to mix them deliberately. Bronze was better for tools and weapons (such as swords, axes, spears

and shields) as it was harder and had a lower melting point than pure copper, making it easier to shape and sharpen to

produce a better cutting edge. It was also less brittle than stone.

Iron Age: (1000 BCE to 1 CE)

Extraction of iron from ion oxide using charcoal requires a higher temperature than the extraction of copper. It was not

until 1200 BCE that humans developed a method of obtaining iron and of forging iron into tools and weapons. It was

necessary to blow air into the fire to get a sufficiently high temperature, first to extract the iron and then to soften it

enough to forge it.

Tools and weapons made of iron were harder than bronze ones therefore iron had largely replaced bronze for tools and

weapons.

Iron weapons were heated and hammered into shape rather than cast, making them stronger, less brittle, and more reliable

than bronze weapons.

Iron's importance rested in the fact that unlike bronze, which required the use of relatively rare tin to manufacture, iron

was commonly and widely available almost everywhere.

The technology to achieve the higher temperatures needed to extract iron was first developed in Asia, spreading from

there to the Middle East and Europe. An open fire cannot achieve the high temperatures needed, so a furnace must be

built and air pumped in.

The realisation that iron was much more plentiful than copper and thus cheaper, meant that by about 1000 BC iron had

come into general use and replaced bronze for tools and weapons. Today, iron is still the most widely used and useful

metal in the world.

Copper's main use is in electrical appliances and wiring, although it also has many applications in the areas of

construction, engineering and transport. Properties that contribute to its usefulness include its good conductivity of heat

and electricity, resistance to corrosion and pleasing appearance. Its toxicity to marine organisms, combined with its

resistance to corrosion, has made it very good as a sheathing material for ship hulls and offshore platforms. In the future it

may be used more extensively in superconductors, computer chips and electric vehicles.

Aluminium is well known and has many applications. Its useful properties, such as low density, strength, availability and

ease of recycling, may lead to its increased importance in the future, extending its uses in transport, packaging,

construction, electric cables and as a solid fuel in powdered form.

Window frames – because it’s resistant to corrosion. Aircraft – because it has low density and it’s lightweight. Drink containers

because it’s malleable and resists corrosion

Titanium, present as oxides in beach sands, is a strong, light, silvery metal with many uses ranging from construction of

aeroplanes and surgical implants to paint pigment manufacture. Has the highest strength to weight ratio of any metal as it

is very hard and very resistant to corrosion. Alloyed with small amounts of Aluminium and vanadium it is even stronger

and harder. Titanium is widely used in the aerospace industry (both for outer cladding and in engines), for medical

implants (artificial hips and knees) and for bicycles and other sporting appliances.

Titanium can also produce strong lightweight alloys for aerospace, medical prostheses, orthopedic implants, dental and

endodontic instruments, dental implants, jewelry, mobile phones, and other applications.

An alloy is a mixture containing a metal and one or more other elements. Usually the other elements are metals; however,

non-metals can be used, such as in carbon steel. The substances to be alloyed are melted, mixed and allowed to cool.

Alloys, being mixtures, can vary in composition—they do not have constant composition or properties.

An alloy is a homogenous mixture of a metal with one or more other metals.

Adding small amounts of a metal to another metal can change its properties.

Pure metal: A metal that does not intentionally contain any other material.

Name of alloy Properties of alloy Uses

Stainless steel Resistant to corrosion, Hard, resists abrasion, Shiny Cutlery, Building

Tungsten steel Hard, even when heated Tools for cutting and grinding- blades, drill bits

Zinc-aluminium Resists corrosion Coating on steel for roofs, Wall cladding

Brass Strong Easily worked Resists corrosion (including

effects of salt water), Can be polished

Boats, Musical instruments

Decorative uses, Screws and bolts

Cupro-nickel Resists corrosion, Shiny, silvery appearance Coins—50c, 20c, 10c and 5c coins

Bronze Durable Lower melting point than copper, Easy to cast,

Harder than pure copper

Statues , Medals

Ship propellers

Aluminium bronze Gold colour, Relatively low density $1 and $2 coins

Solder Relatively low melting point of lead, Adheres firmly to

other metals when molten

Joins metals, especially in electronics and

plumbing

An alloy is a metal blended with some other metallic or non-metallic substance to give it special qualities ranging from

the resistance to corrosion, greater inflexibility, or tensile strength. The atoms in a metal are held together by the metallic

bond. In a pure metal the atoms are all the same size and can slip over each other if a force is applied. In an alloy, the

presence of different sized atoms prevents such dislocations from weakening the metal.

Future alloys : Adding a variety of arsenic compounds to a beaker of water containing magnesium (solid magnesium

alloys containing 0.37 per cent arsenic) dramatically reduces rates of corrosion in magnesium. Cars, planes and portable

devices could be much lighter. The researchers found that arsenic acts as a cathodic poison by restricting the ability of

hydrogen atoms to form magnesium Therefore, this new development will make a strong, lightweight structural materials,

capable of reducing fuel consumption and carbon emissions

Ceramic coatings will be used more to protect metals from high temperatures, and to increase the lifetime of tools. New,

radiation-resistant alloys will allow nuclear power plants to operate longer, and thus lower the cost of nuclear energy.

Steel will continue to be the most commonly used metal for many years to come, due to its very low cost and the ability to

customize its properties by adding different alloying elements.

A superalloy, or high-performance alloy, is an alloy that exhibits excellent mechanical strength and resistance to creep

(tendency for solids to slowly move or deform under stress) at high temperatures; good surface stability and corrosion. A

superalloy’s base alloying element is usually nickel, cobalt, or nickel-iron. Typical applications are in the aerospace,

industrial gas turbine and marine turbine industries.

Titanium metal: it has a low density, is strong, lustrous and withstands corrosion. Titanium can be alloyed with iron,

aluminum and vanadium, among other elements, to produce strong lightweight alloys for aerospace, medical prostheses,

orthopedic implants, dental and endodontic instruments, dental implants, jewelry, mobile phones, and other applications. It

is often called the “space age metal” of the future.

Zirconium metal: It is very corrosion resistant and is utilised extensively by the nuclear power industry for containment

tubing and by chemical industry where corrosive agents are used. It is also used to produce getter suspensions in lamps and

vacuum tubes, as an igniter paste for the production of flash tubes and to produce highly reactive and quick fuse

compositions in pyrotechnics for use in ammunition, explosives and airbags. Zirconium metal is a hard, lustrous, greyish-

white metal. It is very corrosion resistant.

The furnace was made of stones and lined with clay. A mixture of charcoal crushed copper ore and iron ore was added and

ignited. The charcoal lined the furnace and covered the top. Air would have been blown in by pipes or pumped in by

bellows, operated by hand or foot. Blowing in air increased the temperature of combustion, making it hot enough to convert

the iron oxide to iron. The copper ore was added to act as a flux, a substance that would combine with waste rock and form

slag. After smelting, the less dense slag would be floating on top so it could be run off, leaving relatively pure iron at the

base of the kiln.

First metal to be extracted from an ore was copper. This occurred in Middle East in about 6000 BCE.

Copper Oxide was heated with charcoal (mainly Carbon) and globules of copper resulted. This copper was used to make

ornaments and possibly a few domestic utensils.

Humans discovered that heat could be used to extract copper from malachite (a green copper containing mineral.)