Pure Metals have the following physical properties …

High Density.

High Melting & Boiling Points.

Good Conductors Of Heat & Electricity.

Malleable.

Ductile.

Lustrous.

High Density

Pure metals is made up of one type of atoms, thus all atoms are of the same size.

The atoms in a pure metals are orderly arranged & closely packed together.

High Melting & Boiling Points

The forces of attraction between the very closely-packed atoms are very strong, thus a large amount of energy is required to overcome these forces.

Ductile

Although the forces of attraction of the atoms are very strong, they are not rigid.

So, when a force is applied, the layers of atoms can slide over one another.

This is why metals are ductile @ can be stretched.

FORCEFORCE

FORCEFORCE

Malleable

The arrangement of atoms in pure metals are not perfect because there are some empty spaces in between the atoms.

So, when a metal is knocked @ pressed, groups of atoms may slide & then settle into new positions.

FORCEFORCE

Alloy is a mixtures of two or more elements with a certain fixed composition in which the major component is a metal.

Characteristics of alloy are, :

Stronger

Harder

Resistant to corrosion

Have a better finish

&

Lustrous

Why Make Alloys ?

To increase the strength and hardness of a pure metal.

To increase the resistance to corrosion of a pure metal.

To improve the appearance of a pure metal.

BRONZE

Composition90% of copper & 10% of tin.

PropertiesHard, strong, does not corrode easily & shiny surface.

BRASS

COMPOSITION70% of copper & 30% of zinc.

PROPERTIESHarder than copper.

Cupro-nickel

COMPOSITION75% of copper & 25% of nickel.

PROPERTIESBeautiful surface, shiny, hard & does not corrode easily.

STEEL

COMPOSITION99% of iron & 1% of carbon.

PROPERTIESHard & Strong.

STAINLESS STEEL

COMPOSITION74% Iron, 8% Carbon & 18% chromium.

PROPERTIESShiny, strong & does not rust.

DURALUMIN

COMPOSITION93% of aluminium, 3% of copper, 3% of magnesium &

1% manganese.

PROPERTIESLight & strong.

PEWTER

COMPOSITION96% of tin, 3% of copper & 1% of antimony.

PROPERTIESShiny, strong, & does not corrode.

9-CARAT GOLD

COMPOSITION37.5% of gold, 11% of silver & 51.5% copper.

PROPERTIESShiny, strong, & does not corrode.