Metals are characterized by their luster, strength, conductivity, and ability to form alloys. Metallic bonding occurs when valence electrons are delocalized and surround atomic nuclei, allowing metals to be malleable and ductile. Ferrous metals contain iron while non-ferrous metals do not. Common ferrous metals include steel alloys while common non-ferrous metals include aluminum and copper. Alloys combine metals to produce materials with improved properties for various applications.

2. METALS
Metals are chemical elements that are known
generally for their metallic luster, strength, hardness,
and ability to conduct heat and electricity. Metals are
generally not used in their pure state but as mixtures
of metals or metal and non-metal constituents
commonly referred to as alloys.

3. THE METALLIC BOND
Is a type of chemical bond formed between
positively charged atoms in which the free electrons are
shared among a lattice of cations. Metallic bonding is
the main type of chemical bond that forms between
metal atoms.

4. In metallic bonds, the valence electrons from the s and p orbitals
of the interacting metal atoms delocalize. That is to say, instead of
orbiting their respective metal atoms, they form a “sea” of electrons
that surrounds the positively charged atomic nuclei of the interacting
metal ions. The electrons then move freely throughout the space
between the atomic nuclei.

5. Properties of Metals
 Metals are lustrous in nature. They have shiny appearance.
 Metals are malleable. Metals are malleable because their atoms can
move past each without breaking the metallic bond, therefore
retaining the structure of the metal.
 Metals are ductile. Metals are ductile for the same reason that the
atoms of metals have the ability to move past each other without
breaking the metallic bond.
 Metals are good conductors of heat and electricity. Metals have
free electrons. They conduct electricity well.

6.  Most metals are hard. Metals tend to be strong because of the
metallic bond that keeps the atoms close together. The soft metals,
on the other hand, include tin, lead, sodium, and copper. Mercury,
which is liquid at room temperature, is also considered a soft metal.
 Most metals have high densities. Metals are generally dense since
their atoms are closely packed together because of the strong
attractive forces. Metals with low densities are sodium, lithium,
cesium, and rubidium.

7. Two types of metals
1. Ferrous Metal- are metals that consist mostly of iron and small
amounts of other elements. It is prone to rusting if exposed to
moisture. It can also be picked up by a magnet.
Commonly used examples of ferrous metals include steel, stainless
steel, carbon steel, cast iron and wrought iron:

8. a.) Steel
A combination of iron and carbon, steel is renowned for its strength
and machinability. It is widely used in construction, manufacturing
and industrial metal fabrication.
b.) Stainless Steel
Stainless steel is an alloy steel made with the addition of chromium
to steel, which provides resistance against rust. It is commonly seen as
kitchen accessories, cutlery, and cookware.
c.) Carbon Steel
Carbon steel contains a high carbon content that is added to iron to
create an exceptionally hard metal that is used for tools.

9. d.) Cast Iron
Cast iron is a hard and wear resistant metal that is widely used for
items including cookware, machine tools, engines, manhole covers
and water pipes.
e.) Wrought Iron
Unlike most other ferrous metals, wrought iron is able to resist
corrosion and oxidation. It is typically used for fences, railings and
gates.

10. 2. Ferrous Metals- are metals that do not have any iron in them at all.
This means that they are not attracted to a magnet and they also do not
rust in the same way when exposed to moisture.
Commonly-used non-ferrous metals include aluminum, lead, silver,
brass, gold, zinc, copper and tin:

11. a.) Aluminum
Lightweight and easy to machine, shape and weld, aluminum is
used for a range of applications from food cans and cookware to
airplane parts and cars.
b.) Copper
A good conductor of heat and electricity, copper is highly ductile
and malleable. It is widely used for electrical wiring as well as in
appliances and vehicles.
c.) Lead
With a low melting point and low tensile strength, lead is used in
electrical power cables, batteries, pipes, fuels, paint and for soldering.

12. d.) Tin
Soft and malleable with a low tensile strength, tin is used as a
coating to prevent steel from corroding.
e.) Silver
Silver is used for a range of applications, including jewelry, cutlery,
electrical contacts and in mirrors.
f.) Brass
Brass is used for fixtures and fittings including taps, hooks, and
doorknobs, as well as being used for light fittings and screws, among
other uses.

13. g.) Gold
Used for jewelry, gold also has applications including within the
medical industry, in computers and also electronics.
h.) Zinc
A medium strength metal with a low melting point, zinc is used to
galvanize iron and steel to prevent rusting.

14. Properties of Ferrous and Non-Ferrous Metals Comparison
Ferrous and non-ferrous metals typically have differing properties,
although there are some exceptions to some of these general rules:
1. Resistance to Rust and Corrosion
Ferrous metals are vulnerable to rust when exposed to the elements
due to their high carbon content. Exceptions to this rule include
stainless steel and wrought iron, which resists rust because of its high
iron content.
Non-ferrous metals have a naturally higher resistance to rust and
corrosion because of the lack of iron content, making them good for
applications including roofing and gutters.

15. 2. Magnetic Properties
Most ferrous metals have magnetic properties. Non-ferrous metals
are not magnetic.
3. Weight
Non-ferrous metals are lighter than ferrous metals.
4. Cost
Non-ferrous metals tend to be more expensive than ferrous metals
due to rarity, although this is not always the case.

16. 5. Recycling
Both ferrous and non-ferrous metals can be recycled. Non-ferrous
metals can be recycled repeatedly as they don’t lose chemical
properties or degrade during recycling. By contrast, ferrous scrap
metals need to be melted, purified and then compacted into solid
blocks.

17. ALLOYS
A metal that is normally very soft and malleable, such as
aluminum, can be altered by alloying it with another soft metal, like
copper. Although both metals are very soft and ductile, the resulting
aluminum alloy will be much harder and stronger. Gold when
combined with copper becomes suitable to make jewels.
The mechanical properties will often be quite different from those
of its individual constituents. Hence alloys play an important role in
engineering materials.
Alloy
Alloys are homogeneous mixture of two or more metals.
Ex. Brass, Bronze, Stainless steel.

18. Purpose of alloying
1. To increase the hardness of the metal.
2. To increase the tensile strength of the metal.
3. To make it corrosion resistant.
4. To enhance the malleability and ductility.
5. To get attractive surface and appearance.
6. To make it abrasion resistant.
7. The machinability of the metal can be improved.
8. Melting point of the metal can be decreased.
9. The color and metallic luster can be improved.

19. Types of alloys
Alloys are classified into two types.
1. Ferrous alloys
2. Non-ferrous alloys
 Ferrous alloys
Alloys which contain containing iron as the main (major)
constituent are called as ferrous alloys.
Examples: Stainless steel, chromium steel and vanadium steel.

20. Name of the alloy Composition Uses
Stainless steel
Chromium = 14%
Carbon = 1%
Nickel = 1%
Iron = 84%
1. Used for making kitchen utensils.
2.Used for making surgical instruments
3.Used for making automobile parts
Chromium steel
Chromium = 0.5-18%
Carbon = 0.15 - 1.3%
Iron = 80.7 - 99.35%
1.Used for making rock cutting machines
2.Used for making files
3.Used for making ball bearings
4.Used for making connecting rods
Vanadium steel
Chromium = 1.1 - 1.5%
Vanadium = 0.5%
Carbon = 0.4 - 0.5%
Iron = 97.5 - 98%
1.Used for making gears and bearings
2.Used for making axles
3.Used for making springs and pistons

21.  Non-ferrous alloys
Alloys which do not contain containing iron as the main
constituent are called as non-ferrous alloys.
Examples: Nichrome, Dutch metal, German silver, gun metal and
duralumin
Name of the
alloy
Composition Uses
Nichrome
Manganese = 02%
Chromium = 12%
Nickel = 60%
Iron = 26%
1.Used in making resistance coils
2.Used for making heating elements in stoves,
electric irons, water heater and toasters

22. Dutch metal
Copper = 80%
Zinc = 20%
1. Used for making cheap jewelry
2. Used for making musical instruments
3. Used for making battery caps
4. Used for making flexible hoses
German
silver
Copper = 50%
Nickel = 30%
Zinc = 20%
1. Used for making coins
2. Used for making ornaments
3. Used for making decorative materials
Gun metal
Copper = 88%
Tin = 10%
Zinc = 02%
1. Used for making bearings
2. Used for making coins
3. Used for making hydraulic Fittings
4. Used in foundry works
Duralumin
Aluminum = 95%
Copper = 04%
Magnesium = 0.5%
Manganese = 0.5%
1. Used in building aircrafts
2. Used for making automobile parts and locomotive
parts
3. Used for making surgical instruments
4. Used for making cables