Pure metal and alloy

3. Pure Metals have the following physical properties …
High Density.
High Melting & Boiling Points.
Good Conductors Of Heat & Electricity.
Malleable.
Ductile.
Lustrous.

4. 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.

5. 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.

6. 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.

7. FORCE
FORCE

8. 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.

9. FORCE

11. 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

12. 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.

14. BRONZE
Composition
90% of copper & 10% of tin.
Properties
Hard, strong, does not corrode easily & shiny surface.

15. BRASS
COMPOSITION
70% of copper & 30% of zinc.
PROPERTIES
Harder than copper.

16. Cupro-nickel
COMPOSITION
75% of copper & 25% of nickel.
PROPERTIES
Beautiful surface, shiny, hard & does not corrode
easily.

17. STEEL
COMPOSITION
99% of iron & 1% of carbon.
PROPERTIES
Hard & Strong.

18. STAINLESS STEEL
COMPOSITION
74% Iron, 8% Carbon & 18% chromium.
PROPERTIES
Shiny, strong & does not rust.

19. DURALUMIN
COMPOSITION
93% of aluminium, 3% of copper, 3% of magnesium & 1%
manganese.
PROPERTIES
Light & strong.

20. PEWTER
COMPOSITION
96% of tin, 3% of copper & 1% of antimony.
PROPERTIES
Shiny, strong, & does not corrode.

21. 9-CARAT GOLD
COMPOSITION
37.5% of gold, 11% of silver & 51.5% copper.
PROPERTIES
Shiny, strong, & does not corrode.