Pure metal and alloy
Transcript of Pure metal and alloy
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.