Aluminium:

• Chemical element in the boron group symbol Al and atomic number 13 with
atomic mass 26.9815385.

Introduction:
• Third most abundant element and the most abundant metal in the
Earth’s crust.
• An inexpensive method was not developed until 1886
for producing pure aluminium.
• Silvery-white metal and non-magnetic.
• Light-weight, non-toxic and can be easily machined or
cast.
• Pure aluminium is soft and ductile , but can be strengthened by alloying with
small amounts of copper, magnesium, and silicion.
• Strongly reactive metal that forms a high-energy chemical bond with oxygen.
• Very active galvanically and will sacrifice itself to any other metal it contacts
directly and indirectly.
• Aluminium weathers far better than iron.
• Due to its versatility, it is the most widely used metal after steel.
Origin and occurrence:
• Firstly, named for one of its most important compounds, alum.
• Alum is a compound of potassium, aluminium, sulfur and oxygen.
• Chemical name is potassium aluminium sulfate, Kal(SO4)2.
• Occur naturally only in compounds, never as a pure metal.
• Occur in all types of clay.
• Available in various forms such as oxides, sulphates, silicates, phosphates, etc.
• Commercially, produced from the ore, bauxite.
• Removing aluminium from its compound is very difficult.
 ALUMINUM ALLOY CLASSIFICATION

Wrought Alloys Cast Alloys

• Both of these are subdivided into heat-treatable and non-heat-treatable types.

• Foundry workers form these alloy types in different ways, which significantly impacts their characteristics.
• Cast alloys are relatively inexpensive to produce because of their low melting point, but they tend to have
lower tensile strengths than their wrought counterparts.
 DIFFERENCE
Wrought and Cast Aluminum: What’s the Difference?

• There are many minor differences between wrought and cast aluminum alloys, such as that cast alloys can
contain more significant amounts of other metals than wrought alloys.
• But the most notable difference between these alloys is the fabrication process through which they will go to
deliver the final product.
• Aside from some surface treatments, cast alloys will exit their mold in almost the exact solid form desired,
whereas wrought alloys will undergo several modifications while in their solid state. This difference will
have a significant impact on the possible forms and physical properties of the final products.
 Al alloys may be classified as:

Non heat treatable alloys Heat treatable alloys

(No significant strengthening can be achieved (Capable of being Precipitation Hardening)
by heating & cooling)

Both types use heating to decrease ( ) and increase ductility

(annealing)( Full annealing and Partial annealing)
Physical Properties:
Atomic number 13
Atomic weight 26.9815384
Melting point 933.47K
Boiling point 2743K
Density 2.70 g/cm3
Heat of Fusion 10.71 KJ/mol
Heat of Vaporization 284 KJ/mol
Molar heat capacity 24.20J/(mol.K)
Vapor Pressure:
P(Pa) 1 10 100 1k 10k

At T(K) 1482 1632 1817 2054 2364

Properties of Aluminium:
• Good conductor of heat and electricity.
• Slivery white metal with a bluish tinge and exhibits bright luster on a freshly
broken surface.
• Non-magnetic substances.
• Highly resistant to corrosion.
• Light weight, malleable, very soft and ductile.
• Possesses great toughness and tensile strength.
• Readily dissolves in HCl.
Characteristics of Aluminium:
• Can be easily recycled easily.
• Almost, all are used in construction.
• High scrape value.
• Non corrosive and non toxic so used for both indoor and outdoor application.
• Resist corrosion by water, snow and moisture without coating.
• Does not strikes spark nor get brittle under extreme cold or heat.
Basic Chemical Properties:

1. Solubility: Aluminium hydroxide [Al(OH)3] is sparingly soluble in water, forming

a colloidal suspension known as aluminium hydroxide gel. This property is utilized
in the treatment of water and wastewater to remove impurities.

2. Combustibility: Aluminium reacts with oxygen in the air to form aluminium

oxide, releasing a significant amount of energy. However, due to the protective
oxide layer, aluminium metal does not combust readily in normal atmospheric
conditions.

3. Acid-Base Properties: Aluminium reacts with both acids and bases. In acidic
solutions, aluminium ions (Al3+) can form complex ions with water molecules. In
basic solutions, aluminium hydroxide [Al(OH)3] forms.
4. Conductivity: Aluminium is a good conductor of electricity and heat. It is
commonly used in electrical transmission lines, heat exchangers, and other
applications where conductivity is important.

5. Non-Magnetic: Aluminium is non-magnetic, which makes it suitable for

applications where magnetic interference needs to be minimized, such as in
electronics and sensitive instruments.

6. Resistance to Corrosion: The protective oxide layer formed on aluminium's

surface provides excellent resistance to corrosion, particularly in acidic
environments. However, aluminium can still corrode in certain conditions, such as
in the presence of strong alkalis or in environments with high humidity and salt
content.
Advanced Chemical Properties:

1. Reduction Potential: aluminium has a high reduction potential, meaning it

can readily donate electrons to other substances. This property makes
aluminium useful in various reduction reactions.

2. Amphoteric Nature: aluminium exhibits amphoteric behaviour, meaning it

can act as both an acid and a base. For example, in the presence of strong
bases, aluminium hydroxide [Al(OH)3]acts as an acid by donating protons.

3. Complex Formation: aluminium can form complex ions with ligands. For
instance, aluminium chloride (AlCl3) can form complex ions such as [AlCl4]-
when dissolved in appropriate solvents.
Electromagnetic Properties
ØElectrical Conductivity :
• The electrical conductivity of aluminum is
approximately 61% that of copper (most commonly
used conductor in electrical applications).
• The conductivity of aluminum is about 37.7 MS/m
(mega siemens per meter) at room temperature.
ØResistance :
• The resistance of aluminum is higher compared to
copper due to its lower conductivity.
• However, aluminum still offers sufficiently low
resistance for many electrical applications.
Magnetic Properties
ØDiamagnetic Material
• Aluminum is a diamagnetic material, which means it exhibits a weak repulsion to magnetic
fields.
• When exposed to a magnetic field, aluminum generates an opposing magnetic field, causing
it to repel from the magnet.
• This property makes aluminum non-magnetic and prevents it from being attracted to
magnets.
Applications of Aluminum
ØConstruction:
• Aluminum is widely used in the construction industry for windows, doors, and structural
components.
ØPackaging:
• Aluminum foil is commonly used for packaging food and beverages.
ØTransportation:
• Aluminum is used in the automotive and aerospace industries for its lightweight and
corrosion-resistant properties.
ØElectrical Wiring:
• Aluminum wiring is commonly used in residential and commercial buildings. It is a cost-
effective alternative to copper wiring and provides good conductivity for electrical currents.
ØElectromagnetic Shielding:
• Aluminum is used for electromagnetic shielding to protect electronic devices from
electromagnetic interference. It acts as a barrier, preventing external electromagnetic waves
from affecting the performance of sensitive components.
ØPower Transmission:
• Aluminum is widely used in power transmission due to its excellent conductivity and low
weight.
• It is an essential material for overhead power lines, allowing for efficient and reliable
electricity distribution.
ØMRI machines:
• Aluminum is used in the construction of MRI machines to minimize magnetic interference
and provide accurate imaging results.
LIMITATIONS

Lower Melting Point Lower Hardness Higher Cost

Aluminum alloys' melting Aluminum’s relative softness In some applications,
point is lower than most other means it can’t withstand as aluminum alloys may not be as
structural metals, making them much wear as certain other cost-effective as other
potentially unsuitable for high- materials. materials.
temperature applications.
Copper
ØCopper is a chemical element with symbol Cu. Its name come from the
Latin name- cuprum .
ØIt is a ductile metal with very high thermal and electrical conductivity.
ØPure copper is soft and malleable.
ØCopper is present in the earth’s crust at a concentration of about 50
parts per million (ppm).
ØCopper is found as native metal and in minerals i.e. cuprite, azurite,
chalcopyrite and bornite. Sulphides, oxides and carbonates are the
most important ores.
ØIt is used as a conductor of heat and electricity, a building material and
a constituent of various metal alloys.
Physical properties
ØName, symbol :- copper, Cu
ØAppearance :- Red-orange metallic luster
ØMostly found :- Ore form
ØMetal :- Non ferrous metal
ØAtomic number :- 29
ØGroup, block :- Group II , d-block (of periodic table)
ØMelting point :- 1084.62 °C
ØBoiling point :- 2562 °C
ØDensity :- 8.96 g/㎤
ØStandard atomic wt :- 63.546 g/mol
Composition
ØCopper is a pure element with atomic number 29. That means
an atom of copper has 29 protons in the nucleus and 29
electrons surrounding it.
ØCopper has two stable isotopes 63cu and 65cu containing 34
and 36 neutrons respectively in the nucleus, as well as a number
of unstable radioactive atoms exists in copper.
Structure
ØCopper has a face centered cubic (FCC) crystal
structure.
ØIt has 6 atoms at the center of all 6 faces and 8
atoms at all 8 corner positions.
ØThis arrangement results in a close-packed structure
with a coordination number of 12, meaning each
copper atom is in contact with 12 neighboring
copper atoms.
Ores of copper
ØCopper ores are rocks or minerals from which copper can be
extracted.
ØThe main ore of copper is chalcopyrite. It is the most abundant
copper-bearing mineral and accounts for approximately 70-80% of
the world's known copper reserves.
Resistivity
ØThe resistivity of a conductor is defined as the resistance
offered by the material per unit length for a unit cross-
section.
Ø It is denoted by the symbol ρ
Ø Resistivity of copper = 16.78×10-9 nΩ•m at 20 °C.
Conductivity

ØElectrical conductivity is a measure of how well a material

transports an electric charge.
ØIs an essential property in electrical wiring systems.
ØConductivity annealed copper = (5.8001 x 107S/m) at
20°C .
Specific heat capacity
ØThe amount of heat required to raise the
temperature of 1kg of substance by 1 degree Celsius.
Ø(J/kg ∙ K, cal/g ∙ K, Btu/lbm ∙ °F).
ØC = (dQ /dT×m)
ØCapacity:- 0.4J/g.K in case of copper
Thermal conductivity
ØThermal conduction is the phenomenon by which heat is
transported from high- to low-temperature regions of a
substance.
ØThe property that characterizes the ability of a material to
transfer heat is the thermal conductivity.
ØQ= = −k dT dx
ØAt 300K thermal conductivity= 470W/m.K.
In case of copper
ØCopper itself is not magnetic.

ØA magnetic field is produced by a copper wire only

when it is carrying an electric current. The wire could
be straight, solenoid or toroidal.
In case of copper
ØCopper(i):- diamagnetic
Ø Copper(2+):- paramagnetic.

Why?
ØCu (I) is diamagnetic because its d-subshell is fully filled.
ØCu (2+) is paramagnetic because there is one unpaired
electron.
In case of copper
ØCopper cannot be ferromagnetic.
ØFor metals to be ferromagnetic they should have an unpaired electron.
Ø Because copper has a fully [3d] shell therefore it does not have an
unpaired electron and therefore it cannot be ferromagnetic material.
Application of copper
Øfor making electrical parts,
ØHeat exchangers,
ØScrew machining product,
ØFor making various copper alloys such as brass and bronze,
ØFor household utensils, etc.
What is Hastealloy?

Ø Trademark named for the high performance alloy developed by Hayes International

Ø Alloy made with nickel-chromium-molybdenum material with their excellent

corrosion resistance, high temperature resistance and strength

Ø Commonly used industries like aerospace, chemical processing, marine engineering

and nuclear power generation
General Properties of Hastealloy

Ø It possess 1%- 25% chromium, 5% - 30% molybdenum,0 – 30% iron and balance
amount of nickel.
Ø Microelements like cobalt, tungsten, vanadium, titanium and other elements are added to
according to requirements.
Ø Generalize Properties of hastealloy
Excellent corrosion resistance
Density: 8.89 g/cm^3
Melting Range: 1323-13710C
Tensile Strength: 690 to 783 MPa
Good weldability
High-Resistance against oxidizing agents and acids
Electrical Properties
Hastelloy alloys are moderately good conductors of electricity, with
electrical resistivity values typically ranging from 114 to 130 microhm-cm
at room temperature.

Source: Researchgate.com
Electrical properties(continued)
• The electrical properties of haste alloys can vary depending on their specific composition and
processing.
• Some haste alloys may exhibit good electrical conductivity, while others may have lower
conductivity due to the presence of alloying elements that hinder electron flow.
• In applications where electrical conductivity is a significant consideration, haste alloys may not be
the optimal choice compared to other materials specifically designed for electrical conductivity,
such as copper or aluminum.
• However, haste alloys are often chosen for their mechanical properties in high-temperature and
corrosive environments, with electrical conductivity being a secondary consideration.
Mechanical Properties of Hastealloy

Hastelloy alloys are prized for their combination of corrosion resistance and
mechanical properties, making them suitable for use in a wide range of demanding
applications, including chemical processing, aerospace, marine, and oil and gas
industries.

https://lkalloy.com/a-
complete-introduction-
of-hastelloy-bcg-alloy-
for-chemical-industrial/
 Mechanical Properties(continued)
Ø Tensile Strength: Hastelloy alloys typically exhibit high tensile strength, often ranging from
around 600 MPa (87 ksi) to 1000 MPa (145 ksi) or higher, depending on the alloy composition
and heat treatment.
Ø Yield Strength: The yield strength of Hastelloy alloys is typically in the range of 250 MPa (36
ksi) to 700 MPa (101 ksi) or higher. This is the stress level at which the material begins to
deform plastically.
Ø Elongation: Hastelloy alloys generally have good ductility, with elongation values ranging
from approximately 20% to 50% or more. This indicates the material's ability to deform before
fracture under tensile loading.
Ø Hardness: Hastelloy alloys typically have a hardness ranging from around 150 to 300 on the
Brinell hardness scale (HB), depending on the specific alloy and heat treatment. This provides
resistance to abrasion and wear.
Ø Fatigue Strength: Hastelloy alloys often exhibit good fatigue strength, allowing them to
withstand repeated loading and unloading cycles without failure. The fatigue strength can vary
depending on factors such as alloy composition, heat treatment, and testing conditions.
Ø Creep Resistance: Hastelloy alloys are known for their excellent creep resistance, enabling
them to maintain their mechanical integrity under sustained load at elevated temperatures over
time. This property is crucial in high-temperature applications.
MAGNETIC PROPERTIES
• Hastelloy alloys, like many other nickel-based alloys, typically exhibit weak
magnetic properties. In general, nickel-based alloys are known for their low
magnetic permeability, meaning they are not strongly attracted to magnets and do
not retain magnetism when the magnetic field is removed.
• The low magnetic permeability of hastelloy alloys is due to their specific
composition, which often includes significant amounts of nickel and other non-
magnetic elements such as chromium, molybdenum, and cobalt. These alloying
elements help to stabilize the austenitic structure of the alloy, which contributes to
its low magnetic susceptibility.
• However, it's important to note that the magnetic properties of hastelloy alloys can
vary depending on their exact composition, processing conditions, and any
subsequent heat treatments. Some variations of hastelloy alloys may
 THERMAL PROPERTIES

v Hastelloy alloys are renowned for their excellent thermal properties, which make them highly
suitable for use in high-temperature environments.
v Some of the key thermal properties of Hastelloy alloys include:

v High Temperature Resistance: Hastelloy alloys are designed to withstand high temperatures
without significant degradation. They can maintain their mechanical
strength and structural integrity even at elevated temperatures, often up to 1000°C
(1832°F) or higher, depending on the specific grade.

v Thermal Expansion: Like most metals, Hastelloy alloys expand when heated and contract when
cooled. The coefficient of thermal expansion (CTE) of Hastelloy alloys
is relatively low compared to some other materials, which means they experience minimal
dimensional changes with temperature variations. This property is crucial for applications
where dimensional stability is critical.
v Thermal Conductivity: Hastelloy alloys generally have moderate to high thermal
conductivity, which allows them to efficiently transfer heat. This property is
beneficial in applications where heat dissipation or thermal management is
important, such as in heat exchangers and high-temperature processing equipment.
v Thermal Stability: Hastelloy alloys exhibit excellent thermal stability, meaning
they do not undergo significant phase changes or microstructural alterations at high
temperatures. This stability contributes to their reliability and longevity in
demanding thermal environments.
v Resistance to Thermal Fatigue: Hastelloy alloys are highly resistant to thermal
fatigue, which occurs due to repeated heating and cooling cycles. This resistance is
crucial in applications subjected to cyclic thermal loading, such as gas turbines,
exhaust systems, and chemical processing equipment.

Overall, Hastelloy alloys are prized for their exceptional thermal properties, making
them indispensable materials in industries where high-temperature performance and
reliability are paramount, such as aerospace, chemical processing, power generation,
and oil and gas.
APPLICATIONS OF HASTELLOY
Hastelloy alloys find extensive applications across various industries due to their
exceptional combination of corrosion resistance, high-temperature strength,
and durability. Some common applications of Hastelloy alloys include:

1. Chemical Processing: Hastelloy alloys are widely used in the chemical processing
industry for equipment such as reactors,
heat exchangers, piping systems, and valves. They resist corrosion from a wide range of
aggressive chemicals, including acids,
chlorides, and oxidizing agents.
Source: Serenik.com
2. Aerospace: In aerospace applications, Hastelloy alloys are used in components subjected to
high temperatures, such as gas turbine engines, combustion chambers, and exhaust systems.
Their high-temperature strength and resistance to oxidation make them ideal for these
demandingenvironments.

Source: Haynes international

3. Oil and Gas: Hastelloy alloys are employed in oil and gas exploration, production, and refining operations. They
are used in downhole equipment, valves, pumps, and pipelines where exposure to corrosive fluids and high
temperatures is common.

Source: Titan image

4. Power Generation: Hastelloy alloys play a vital role in power generation facilities, including
nuclear, fossil fuel, and renewable energy plants. They are used in steam turbines, boilers, heat
exchangers, and other critical components exposed to high temperatures, steam, and
corrosive environments.

Source: power.org
5. Petrochemical Processing: In petrochemical plants, Hastelloy alloys are utilized in
equipment for refining, distillation, and chemical synthesis. Their resistance to corrosion from
sulfuric acid, hydrochloric acid, and other aggressive chemicals makes them suitable for these
applications.

Source: power.org
6. Marine and Offshore: Hastelloy alloys are used in marine and offshore structures where corrosion
resistance is essential due to exposure to seawater and harsh environmental conditions. They are
employed in marine equipment, seawater desalination plants, and offshore drilling rigs.

Source: marine.pic
7. Pharmaceutical and Biotechnology: Hastelloy alloys are utilized in pharmaceutical and
biotechnology manufacturing processes where corrosion resistance and cleanliness are
critical. They are used in reactors, vessels, and piping systems for the production of
pharmaceuticals, specialty chemicals, and biopharmaceuticals.

Source: doc.org
8. Environmental Protection: Hastelloy alloys are employed in pollution control systems, waste
treatment facilities, and scrubbers for the removal of corrosive gases and pollutants from
industrial exhaust streams.

Source: doc.org
 What is PVC (PolyVinyl Chloride)?
• Polyvinyl Chloride (PVC or Vinyl) is an economical and versatile thermoplastic
polymer.
• It is widely used in the building and construction industry to produce door and
window profiles.
• It also finds use in:
Ø drinking and wastewater pipes,
Ø wire and cable insulation,
Ø medical devices, etc.
• It is the world’s third-largest thermoplastic by volume after polyethylene and
polypropylene.
 General properties
Polyvinyl chloride (PVC) is a versatile and widely used synthetic polymer.

• Chemical structure:
PVC is a type of thermoplastic polymer made
from vinyl chloride monomers.
• Flammability:
when it does burn, it releases hydrogen
chloride gas, which can be harmful.
• Water Resistance:
PVC is resistant to water and moisture,
 • Colorability:
PVC can be easily colored during the
manufacturing process,

• Recyclability:
PVC is recyclable, but its recycling process can
be challenging due to the presence of
additives.

• Chemical Resistance:
PVC is resistant to a wide range of chemicals,
acids, alkalis, and oils.
Eectrical properties of PVC
Polyvinyl chloride (PVC) is widely used in the electrical industry due to its excellent
electrical insulation properties.
• Dielectric Constant (ε):
The dielectric constant is a measure of a material's ability
to store electrical energy in an electric field.
• Dielectric Strength:
PVC exhibits high dielectric strength so crucial for
insulating electrical components and cables.
• Surface Resistivity:
PVC also has high surface resistivity, which is important for
preventing current leakage along the surface of electrical
insulating materials.
 • Electrical Insulation:
used for electrical cable insulation, pipes, and various other
applications in the electrical industry.
• Arc Resistance:
it can resist the formation and propagation of electric arcs.
• Flame Resistance:
While PVC itself is inherently flame-resistant, the additives
used in its formulation can affect its flame-retardant
properties.
• UL Ratings:
PVC materials used in electrical applications often carry
Underwriters Laboratories (UL) ratings, ensuring they meet
specific safety and performance standards.
 Due to these electrical properties
PVC is used for
Øinsulation
Øjacketing in electrical cables
Øwiring, and
Øvarious electrical components.
It provides a cost-effective solution with good
overall performance in electrical applications.
Thermal properties of PVC
 Mechanical properties of pvc
• Tensile Strength:
PVC has a good tensile strength, providing it with the ability to withstand stretching
forces without breaking.
• Elongation at Break:
PVC can exhibit a relatively low elongation at break, indicating limited stretchability.
However, the addition of plasticizers can enhance its flexibility, increasing the
elongation at break.
• Flexural Strength:
PVC is known for its high flexural strength, making it resistant to deformation under
applied bending loads,structural material.
 • Hardness:
• PVC is inherently a rigid material,The addition of plasticizers can make PVC more
flexible, while rigid formulations are used for applications requiring hardness.
• Shear Strength:
• PVC has good shear strength, indicating its ability to resist forces applied parallel to
its surface.
• Abrasion Resistance:
• PVC exhibits good resistance to abrasion, making it suitable material is exposed to
wear or friction.
• Creep Resistance:
• PVC generally has low creep, meaning it resists deformation over time when
subjected to constant load or stress.
 • Flexural Modulus:
• PVC has a high flexural modulus, reflecting its stiffness and rigidity. The flexural
modulus is an important parameter under bending stress.
• Compressive Strength:
• PVC exhibits good compressive strength, making it capable of withstanding loads that
tend to squeeze or crush the material.

• Impact Strength:
• PVC has relatively good impact strength, but it can vary depending on the specific
formulation. The addition of impact modifiers can enhance the material's ability to
resist sudden blows or impacts.
 • Fatigue Resistance:
• PVC has reasonable fatigue resistance, allowing it to withstand repeated cycles of
stress without significant degradation.
• Stiffness:
• PVC is known for its stiffness, which is a result of its high modulus of elasticity. This
property contributes to its use in applications where dimensional stability and rigidity
are important.
• Dimensional Stability:
• PVC tends to maintain its shape and dimensions under various conditions,
contributing to its dimensional stability.
Application of PVC

§ Construction
§ Automotive
§ Medical
§ Clothing and Footwear
§ Synthetic Leather
§ Sports and Leisure
§ Signage and Graphics
§ Packaging
§ Waterproofing
§ Furniture
 What Is the Purpose of Polyvinyl Chloride?
• Polyvinyl chloride (PVC) does not have one
specific purpose as
it is a versatile material used for various
applications.
• For example :
Ørigid PVC is often used for piping
systems, whereas
Øflexible PVC is often used for chemically
resistant personal protective equipment
like raincoats and gloves.
 Is PVC recyclable?
• Products made from PVC are 100% recyclable. They
can be identified as recycling code #3.
• Adopting an appropriate recycling pathway for PVC
is of economic value and has an environmental
benefit.
 Is PVC recyclable?
Key methods for PVC recycling
• Mechanical Recycling
Ømechanically separated
Øground
Øwashed and
Øtreated
• Chemical Recycling
ØMonomers
ØOther substances
• Feedstock Recycling
Recycled PVC can be used

Ø to produce packaging,
Ø film and sheet,
Ø loose-leaf binders,
Ø pipes,
Ø carpet backing,
Ø electrical boxes,
Ø cables and more, etc.
Is polyvinyl chloride toxic?
Limitations of PVC

• Poor heat stability

• Environmental impact
• Temperature Sensitivity:
• Flammability:
ØHydrogen Chloride Emission

• Recycling Challenges
• Limited Transparency
• Properties can change with time, due
to plasticizer migration
 TEFLON
• Teflon is a synthetic fluoropolymer made up of tetrafluoroethylene monomer. Its
chemical name is poly (1,1,2,2 tetrafluoroethylene) and its chemical formula is
(C2F4) n.
• Teflon is a thermoplastic polymer, which means it can be melted and reshaped and has
a melting point of 327 °C.
• Teflon has a very low coefficient of friction, which makes it an excellent non-stick
coating for pans and other cookware.
• It is also very unreactive, which makes it suitable for containers and pipework for
corrosive chemicals.
 MANUFACTURE OF PTFE
• PTFE is a linear polymer of tetrafluoroethylene (TFE). It is manufactured by a free-
radical polymerization mechanism in an aqueous media via the addition
polymerization of TFE in a batch process.
• The net equation is:
 PHYSICAL PROPERTIES
• PTFE is a white solid at room temperature
• Density: 2200kg/m3
• Melting point: 327oC (600 K)
• Undergoes depolymerisation above 650-700oC
• Coefficient of friction: teflon has extremely low coefficient of friction of about 0.05 to
0.10 (third lowest of any known solid material) making it very slippery
• Has low Surface energy of about 19.1mJ/m2 meaning a weak molecular attraction,
therefore harder to bond.
 PHYSICAL PROPERTIES
• Hydrophobicity: PTFE being a fluorocarbon solid, is hydrophobic in nature(i.e.
neither water nor water-containing substances wet PTFE) due to high electronegativity
nature of fluorine and low electric polarizability of fluorine
 CHEMICAL PROPERTIES
• Chemical inertness: Teflon is a non-polar, hydrophobic material does not react with
most chemicals and is resistant to a wide range of chemicals, including acids, bases,
and organic solvents.
• Inert to solvents: it is inert to most solvents, which contributes to its chemical resistance
and non-stick properties
• Non-reactive with food: doesn’t impart any taste or odor to food items cooked on it
• Resistance to oxidation: maintains its properties even in the presence of oxygen at
elevated temperatures
 ELECTRICAL PROPERTIES
• Dielectric strength: refers to the measure of a material’s ability to sustain high-voltage
differences without current breakdown. Teflon has high dielectric strength of 60MV/m
• Dissipation factor: refers to the measure of electrical energy absorbed and lost when a
electrical current is applied to a material. It indicates the inefficiency of material to hold
energy or behave as an insulating material. The lower the dissipation factor, the more
efficient the insulator system. Teflon has a low dissipation factor of 0.0004
 ELECTRICAL PROPERTIES
• Dielectric constant: refers to the ability of a material to store electrical energy. Teflon has
a low dielectric constant of 2.1.

High dielectric strength, low dissipation factor and low dielectric constant collectively make
Teflon an excellent electrical insulator.
 THERMAL PROPERTIES
• Thermal conductivity: refers to measure of the ability of a material to conduct heat.
Teflon has low thermal conductivity off 0.25 W/m.K making it a good thermal insulator.
• High thermal stability: retains its properties over a wide range of temperatures.
• Heat resistance: it can withstand high temperatures without significant degradation.
 MAGNETIC PROPERTIES
• Magnetic permeability: This is a measure of how well a material responds to a magnetic
field. Teflon has a very low magnetic permeability of about 1.000000021, which is close
to that of vacuum. This means that it is not suitable for use in applications where
magnetic properties are important, such as in transformers, motors, or generators.

• Magnetic susceptibility: This is a measure of how easily a material can be magnetized by

an external magnetic field. Teflon has a negative magnetic susptibilityof about -9.1 *
10^-62, which means that it is weakly repelled by a magnetic field. This is a property of
diamagnetic materials, which have no permanent magnetic moments.
 MAGNETIC PROPERTIES
• Magnetic moment: Teflon has no magnetic moment, which means that it does not have a
north or a south pole. This is because it does not have any electric currents or magnetic
dipoles in its structure.
 MECHANICAL PROPERTIES
Tensile Strength
• Typically between 2800-6000 psi depending on specific grade and processing method
• Measures how much tensile stress Teflon can withstand before failure
Hardness
• Shore D hardness of 50-60
• Measurement of material's resistance to indentation; higher values indicate harder
materials
Compressive Strength
• Can withstand compressive stresses exceeding 6500 psi
• Measures maximum compressive load material can handle before deforming
 MECHANICAL PROPERTIES
Ductility
• Ductility measures how much a material can stretch or elongate before it fractures.
• Teflon is highly ductile for a fluoropolymer, with elongation at break values ranging
from 200-600%.
• This indicates it can stretch to 2-6 times its original length when pulled under tension
before breaking.
Creep Resistance:
• Creep refers to the tendency of a material to slowly deform under sustained loading over
time.
• Teflon has extremely high creep resistance.
• Very low creep strain rates on the order of 10-4 % per hour for Teflon at room
temperature and at elevated temperatures between 200-250°C under applied stresses of
500-2000 psi over thousands of hours.
 MECHANICAL PROPERTIES
Fatigue Strength
• Fatigue strength measures how well a material withstands repeated applied stresses
without failure.
• Teflon maintains excellent fatigue strength, retaining over 90% of its initial 2800-6000
psi tensile strength after being subjected to more than 10 million stress cycles from 0 to
2000 psi.
 APPLICATIONS OF TEFLON
Non-stick cookware: Teflon’s superior non-stick properties make it a popular choice for
cookware coatings, ensuring effortless food release and easy cleaning.

Electrical appliances: Teflon has excellent electrical insulation and heat resistance properties,
making it suitable for wire coatings, cable jackets, connectors, and circuit boards.

Personal care products: Teflon is used to make dental floss, hair curlers, hair dryers, and
cosmetic brushes, as it reduces friction and static electricity.

Fabric: Teflon is used to make stain-resistant and water-repellent fabrics, such as carpets,
upholstery, clothing, and outdoor gear.

Aerospace industry: Teflon is used to make seals, gaskets, hoses, bearings, and other
components that can withstand high temperatures and pressures, as well as corrosive
chemicals and fuels.
 APPLICATIONS OF TEFLON
• Semiconductors: Teflon is used to make protective coatings and films for semiconductor devices, as it has
low dielectric constant and high chemical resistance.

• Musical instruments: Teflon is used to make slides, valves, and pads for brass and woodwind instruments, as
it reduces friction and noise, and improves durability.

• Ski bindings: Teflon is used to make anti-friction devices for ski bindings, as it reduces the risk of injury by
allowing the skier to release from the binding in case of a fall.

• Food industry: Teflon is used to make conveyor belts, baking trays, molds, and packaging materials for the
food industry, as it prevents sticking and contamination, and facilitates cleaning.
 Titanium
• Titanium is a transition metal found in nature only as a oxide.
• It is two times stronger than aluminium and 45%lighter than
steel with comparable strength
• Titanium's natural resistance to corrosion allows for
applications in harsh environments, including under sea water.
As a metal, titanium is recognized for its high strength-to-
weight ratio. It is a strong metal with low density that is quite
ductile (especially in an oxygen-free environment), lustrous,
and metallic-white in color.
• The relatively high melting point makes it useful as a
refractory metal.
NATURAL FORM
• Not found in its free pure metal form in nature but as oxides, i.e., ilmenite(FeTiO3)and
rutile (TiO2).
•It can form several oxides – TiO, Ti2O3, TiO2 – of which TiO is the
most common and stable form.

Rutile
Ilmenite
GENERAL
INFORMATION
•Symbol: Ti
•Electronic configuration: [Ar] 3d² 4s²
•Atomic number: 22
•Atomic mass: 47.867amu
•5 stable isotopes
•4 unstable isotopes

Fig: electronic configuration of

titanium
PHYSICAL PROPERTIES
••Boiling point:3287 °Celsius
•Melting point:1668 °Celcius
•Density:4.54g/cc
•Appearance: Shiny, dark-gray metal
•Oxidation States:4,3
COMPOSITION
Natural titanium consists of five stable isotopes:
•titanium-46 (8.0 percent),
• titanium-47 (7.3 percent),
• titanium-48 (73.8 percent),
• titanium-49 (5.5 percent),
•titanium-50 (5.4 percent).
STRUCTURE

Pure titanium can crystallize in two crystal

structures:
• α titanium :
When titanium crystallizes at low temperatures
(room temperature), the hexagonal close-packed
(HCP) structure of alpha titanium is formed.

• β titanium: Fig a: α Fig b:β titanium

While titanium crystallizes at high temperatures, the titanium
body-centered cubic (BCC) structure of beta titanium
is formed. The complete transformation from one to
another crystal structure is called allotropic
transformation. The respective transformation
temperature is called the transus temperature.
 KEY FEATURES
•Corrosion Resistant: Titanium is highly resistant to corrosion from seawater, chlorine, and many other
corrosive agents, making it useful in marine, and chemical processing applications.
•Lightweight: Titanium has a low density compared to many other metals. It is ideal for use in
lightweight structures and components in the aerospace and automotive industries.
•High Strength: Titanium’s strength rivals that of steel. A titanium structure of equivalent strength,
however, weighs approximately 45% less than the corresponding steel structure because of titanium’s
lower density. Because of its high strength and high strength-to-weight ratio, titanium is often used in
aerospace, automotive, medical, and marine applications.
•Biocompatible: Titanium is considered the most biocompatible metal due to its inertness, its resistance
to corrosion by bodily fluids.
•Heat Resistant: Titanium has low thermal conductivity. This makes titanium ideal for high-heat
applications in machining, spacecraft, jet engines, missiles, and automobiles.
• Nonmagnetic: Titanium is nonmagnetic, but becomes paramagnetic in the
presence of a magnetic field.
• Ductile: Titanium is a ductile metal whose ductility improves with increased
temperatures. Additionally, alloying titanium with other ductile metals like
aluminum significantly improves its ductility.
• Low Thermal Expansion: Titanium has a low coefficient of thermal expansion.
At extreme temperatures, titanium will not expand or contract as much as
other materials such as steel. Its low thermal expansion properties make
titanium ideal for structural applications that experience high temperatures
such as in aerospace and spacecraft or large buildings and skyscrapers in the
event of a fire.
• Excellent Fatigue Resistance: Titanium has excellent fatigue resistance. This
makes titanium ideal for aerospace applications where structural parts of
aircraft such as landing gear, hydraulic systems, and exhaust ducts are
subjected to cyclic loading.
MECHANICAL
PROPERTIES
•Strength: Tensile strength ranging from 550 MPa to 950 MPa
•Ductility: Moderately ductile metal
•Hardness: Relatively high,36 to 43 on Rockwell C scale(HRC)
•Elastic modulus: low (105 Gpa)
•Fatigue Strength: Excellent (50% to 60% of its tensile strength)
•Toughness: Demonstrates good toughness, resistance to cracking and fracture under
impact
 ELECTRICAL PROPERTIES
•Electrical Conductivity: Low (3.1% IACS)
•Resistivity:42 micro-ohm centimeters at room temperature
•Temperature Coefficient of Resistance: positive temperature coefficient of resistance
•Super conductivity: Not a superconductor at standard temperatures and pressures
•Corrosion Resistance: Excellent corrosion resistance
•Oxidation: Forms protective oxide layer on its surface which acts as an electrical
insulator
•Electronic and ionic conduction: Metallic bonding enables electronic conduction while
titanium itself does not exhibit ionic conduction.
THERMAL PROPERTIES

•Thermal conductivity: Low(21.9W/m-k at room temperature)

•Coefficient of thermal expansion: Moderate (8.6*10^-6/ ° Celcius)
•Heat resistance: Excellent heat resistance properties
•Thermal stability: Retains its properties and does not undergo significant changes under
thermal stress
•Thermal Shock Resistance: Can withstand rapid temperature changes without underdoing
damage
•Specific Heat Capacity: 26.06 J/Mol °c
MAGNETIC
PROPERTIES
ØParamagnetic material
•Titanium is considered to be weakly paramagnetic, meaning it exhibits a very weak
attraction to magnetic fields.
•This property arises from the presence of unpaired electrons in its atomic structure.
•it has four unpaired electrons in its 3d orbital, which makes it exhibit paramagnetic
behavior.
APPLICATIONS

ØJewellery
•Titanium is commonly used in jewelry to make piercings, wristwatches, necklaces, rings,
and other items due to its durability, light weight, and corrosion resistance. Additionally,
titanium is sometimes mixed with gold to make 24-karat gold alloys which are harder and
more durable than pure gold alternatives.
•
ØAerospace
•Titanium is highly valued in aerospace for its low density, exceptional strength-to-weight
ratio, corrosion resistance, and fatigue resistance. It's a top choice for critical components
like landing gear, firewalls, and hydraulic systems, often constituting around 50% of an
aircraft's total weight.
ØMedical
•Titanium is often used in surgical and dental tools, implants, and joint
replacements. Osseointegration, the ability of a bone and artificial implant to
form a structural and functional connection, is possible with titanium

ØIndustrial
• Titanium's strength, fatigue resistance, corrosion resistance, light weight, and
durability make it a popular choice across various industries. It's used in a wide
range of applications such as heat exchangers, tanks, reactors, valves, pipes,
connecting rods, pumps, and more.

ØArchitecture
•Titanium finds favor in architectural applications like glass frames, facades,
roofs, interior walls, and ceilings because of its corrosion resistance and
impressive strength-to-weight ratio, though steel remains the primary choice
for frames.
ØAutomotive industry
•It's commonly used in engine parts, crankshafts, valve seats, connecting rods,
exhaust and suspension systems, as well as automotive frames. These properties
not only enhance aerodynamics and performance but also contribute to cost-
effectiveness by requiring less material for specific applications.
•
ØChemical processing
•Titanium is favored in the chemical processing industry for its corrosion
resistance and chemical inertness. Although its reactivity rises at higher
temperatures (>700 °F), it remains stable and unreactive at lower
temperatures. Commonly used in pipes, flanges, tubing, tanks, pumps, and heat
exchangers, titanium provides durability and reliability in corrosive
environments.
LIMITATIONS OF TITANIUM

•Reactive at High Temperatures: Titanium is usually inert because of its protective oxide layer, but it
becomes reactive at temperatures above 700°F. Thus, the fabrication of pure and alloyed titanium is
complex and requires meticulous control, necessitating production in oxygen-free environments.
•Expensive: Refining raw rocks and minerals to obtain pure titanium is expensive and complex. This is
due to titanium’s reactivity at high temperatures and the breadth of processes within the Kroll process
needed to isolate titanium.
•Difficult to Machine: Titanium can be difficult to machine due to its low thermal conductivity. The heat
generated during machining builds up in the tool rather than the workpiece. This can lead to reduced tool
life and machining quality.
•Low Unstable Creep Resistance: Titanium has low creep resistance at high temperatures above 570 °F.
Creep is the slow deformation of a material when subjected to constantly applied loads and is more
prevalent in high-temperature environments.
Steels

Steels are iron-carbon alloys that may contain appreciable

concentrations of other alloying elements with iron (Fe) as the base
metal.

Depending on the temperature, it can take two crystalline forms (allotropic

forms): body-centered cubic (BCC), and face-centered cubic (FCC).

an FCC reduced-sphere unit cell BCC tetragonal unit cell for martensitic steels
showing iron atoms (circles) & sites that may be
occupied by carbon atoms (xs)
General Properties of Steel

Steel, characterized by its strength and durability, owes its remarkable properties to its
composition. Typically comprised of iron and carbon, with traces of other elements such
as manganese, phosphorus, sulfur, and silicon, steel undergoes various manufacturing
processes to achieve distinct grades and properties.

Density and Melting Point: The density of steel varies depending on its composition,
but generally falls within the range of 7,750 to 8,050 kg/m³.
This density lends steel its renowned weight-to-strength ratio, making it an ideal choice
for construction and engineering applications.

In terms of melting points, steel typically melts at around 1,370°C (2,500°F), making it
malleable under controlled conditions, allowing for precise shaping and fabrication.
Types of
Steels
Low-Carbon Steels

Of all the different steels, those produced in the greatest quantities fall
within the low-carbon classification and contain less than about 0.25
wt.% C and are unresponsive to heat treatments.

Consequently, these alloys are soft and weak but have outstanding
ductility and toughness; in addition, they are soft and machinable,
weldable, and, of all steels, are the least expensive to produce.

Another group of low-carbon alloys are the high-strength, low-alloy

(HSLA) steels. They contain other alloying elements such as copper,
vanadium, nickel, and molybdenum in combined concentrations as
high as 10 wt.% with higher strengths than the plain low-carbon steels. In
normal atmospheres, the HSLA steels are more resistant to corrosion
than the plain carbon steels.
 Medium-Carbon
Steels
The medium-carbon steels have carbon concentrations between
about 0.25 and 0.60 wt.%. They are most often utilized in the
tempered condition.

These heat-treated
alloys are stronger
than the low-carbon
steels, but at a
sacrifice of ductility
and toughness.

Applications include railway wheels and tracks, gears, crankshafts, and other
machine parts and high-strength structural components calling for combination of
high strength, wear resistance, and toughness.
 High-Carbon Steels

The high-carbon steels, normally having carbon contents

between 0.60 and 1.4 wt.%, are the hardest, strongest, and yet
least ductile of the carbon steels.

These steels are utilized as cutting tools and dies for forming
and shaping materials, as well as in knives, razors, hacksaw
blades, springs, and high strength wire.
Stainless Steel

Stainless steels are highly resistant to corrosion in a variety of environments wherein the
predominant alloying element is chromium (<11 wt.% Cr) and the corrosion resistance may also
be enhanced by the addition of molybdenum and nickel.

Stainless steels are divided into three classes on the basis of predominant phase constituent of the
microstructure- martensitic, ferritic, or austenitic.

Some stainless steels are frequently used at elevated temperatures and in severe environments
because they resist oxidation and maintain their mechanical integrity under such conditions.
Physical
Properties-
Development of
Microstructures
in Steel Alloys
Phase changes that occur upon passing from the γ region into the α+ Fe3C phase field are relatively
complex. For example, an alloy of eutectoid composition (0.76 wt.% C) as it is cooled from a temperature
within the γ phase region, say, 800°C - that is, beginning at point a in the figure and moving down the
vertical line xx’ line. The alloy, initially, is composed entirely of austenite phase having a composition of
0.76 wt.% C and corresponding microstructure. As the alloy is cooled, there will occur no changes within until
the eutectoid temperature (727 °C) is reached. Upon crossing the temperature to point b, austenite
transforms according as:

The alternating α and Fe3C layers in pearlite form because the composition of the parent phase [ austenite
(0.76 wt.% C)] is different from either of the product phases [ ferrite (0.022 wt.% C) and cementite (6.7 wt. %
C)], and the phase transformation requires that there be a redistribution of the carbon by diffusion.

Carbon atoms diffuse away from the 0.022 wt.% ferrite regions and to the 6.7 wt.% cementite layers, as
pearlite extends from the grain boundary into the unreacted austenite grain. The layered pearlite forms
because carbon atoms need diffuse only minimal distances with the formation of this structure.
Phase Transformations
& Heat Treatment

Materials scientists delve into the phase transformations of

steel, particularly the transitions between ferrite, austenite,
and martensite. Engineers exploit these transformations
through heat treatment processes, manipulating the
microstructure to enhance mechanical properties.

Quenching and tempering, for instance, are employed to

achieve desired hardness and toughness in specific steel
components, such as gears or cutting tools.
Chemical Properties- Corrosion Resistance & Alloying Elements

The chemical properties of steel, especially its susceptibility to corrosion, are addressed through strategic
alloying.

Engineers carefully choose alloying elements like chromium, nickel, and molybdenum to impart
corrosion resistance.

Stainless steel, for instance, owes its corrosion resistance to the formation of a passive oxide layer.
Understanding the interplay of these chemical elements is crucial for designing materials with enhanced
durability in harsh environments.
Magnetic Permeability

Magnetic permeability refers to a material's ability to respond to an applied magnetic field by becoming
magnetized. Steel, being ferromagnetic, exhibits a high magnetic permeability compared to non-
magnetic materials. This property makes steel a preferred choice for the cores of transformers and inductors,
where efficient magnetic flux propagation is crucial.

Hysteresis Loss & Magnetic Saturation

Engineers closely study the hysteresis loop of steel. This loop illustrates hysteresis loss, a critical factor in
the design of magnetic components like transformers.

Understanding the material's magnetic saturation point is equally vital. Beyond this point, further increases in
the magnetic field strength do not result in proportional increases in magnetization, affecting the
efficiency of magnetic devices.
 Applications in
Electronic Devices
The unique electromagnetic properties of steel find applications in the design of
electromagnetic devices. Electromagnets, crucial components in various industrial
applications, capitalize on steel's ability to become highly magnetized when an
electric current is applied.

From magnetic locks to electric motors, the controlled and predictable magnetic
response of steel plays a pivotal role in optimizing the performance of these
devices.
Low-Carbon Steel Medium-Carbon Steel
Properties
Properties
∙ Carbon Content: 0.30% to 0.60%
∙ Carbon Content: 0.05% to 0.30%
∙ Weldability: Medium to Low (Susceptible to weld
∙ Weldability: High
hardening, 1060 also requires heating and stress
∙ Hardenability: Low relief if welded)

∙ Machinability: Low (high ductility requires high spindle speeds) ∙ Hardenability: High to Medium (Surface
hardening)
∙ Workability: High
∙ Machinability: High (1030) to Medium or Low
∙ Wear Resistance: Low
(1060)
∙ Specific Strength (strength to weight ratio): Low
∙ Workability: High to Medium or Low (1060 is
∙ Cost: Low susceptible to work hardening)

Material Examples ∙ Wear Resistance: Medium

∙ A36 ∙ Specific Strength (strength to weight ratio): High

to Medium
∙ 1006
∙ Cost: Medium
∙ 1009
Material Examples
∙ 1018
∙ 1030
∙ 1020
∙ 1040
Use Examples
∙ 1045
∙ Civil Structures (Bridges and Buildings)
∙ 1060
∙ Car Bodies
Use Examples
∙ Ships
∙ Crankshafts
∙ Consumer Product Applications
High-Carbon Steel Stainless Steel

Material Properties & Benefits

Properties
∙ High Corrosion Resistance
∙ Carbon Content: 0.60% to 1.00%
∙ Moderate Strength
∙ Weldability: Very Low
∙ Easily Sterilized
∙ Hardenability: Very High
∙ Low Out-gassing Rate (304 Stainless)
∙ Machinability: Low (Susceptible to work hardening)
Material Use Examples
∙ Workability: Low (Susceptible to work hardening)
∙ Cookware
∙ Wear Resistance: High
∙ Surgical Equipment
∙ Specific Strength (strength to weight ratio): High
∙ Industrial Equipment
∙ Cost: High
∙ Storage Tanks
Material Examples
∙ Vacuum Vessels (304 Stainless)
∙ 1080

∙ 1095

Use Examples

∙ Music Wire

∙ Springs

∙ Cutting Tools
Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It
is one of the most abundant elements on Earth and plays a crucial role
in various biological and industrial processes. This metal belongs to the
transition metals group and is known for its strength, malleability, and
conductivity.
Physical Properties:

• State of Matter:
At room temperature, iron is a solid metal.
• Density:
The density of iron is approximately 7.87 grams per cubic centimeter (g/cm³).
It is relatively dense, contributing to its strength and weight.
• Melting Point:
Iron has a high melting point of 1,538 degrees Celsius (2,800 degrees
Fahrenheit). This characteristic makes it suitable for applications requiring
resistance to high temperatures, such as in the production of steel.
• Boiling Point:
The boiling point of iron is much higher, at 2,862 degrees Celsius (5,184
degrees Fahrenheit). However, iron is not commonly used in a gaseous state
in everyday applications.
• Color:
In its pure form, iron has a silver-gray or metallic luster. However, when iron
corrodes, it forms iron oxide (rust), which gives a reddish-brown color.
• Malleability and Ductility:
Iron is both malleable and ductile, meaning it can be easily shaped and
formed into different structures without breaking. These properties make it a
valuable material in construction and manufacturing.
• Conductivity:
Iron is a good conductor of electricity. This property is essential in various
applications, including the production of electrical wires and components.
• Magnetic Properties:
Iron is strongly magnetic, and it can be easily magnetized. This magnetic
property is the basis for the use of iron in the production of magnets and its
presence in Earth's magnetic field.
• Crystal Structure:
At room temperature, iron has a body-centered cubic crystal structure. This
arrangement of atoms contributes to its strength and stability
• Hardness:
Iron is relatively hard, but its hardness can be modified through alloying with other
elements. Steel, which is an iron-carbon alloy, can have varying levels of hardness
depending on the carbon content and heat treatment.
• Tensile Strength:
Iron has high tensile strength, making it suitable for applications where materials
need to withstand pulling or stretching forces.
Chemical properties:
• Reaction with Oxygen:
Iron readily reacts with oxygen in the presence of moisture,
forming iron oxide. This process is commonly known as rusting.
The general equation for the reaction is:
4Fe+3O2​→2Fe2​O3​

• ​Oxidation States:
Iron can exist in different oxidation states, with the most
common being ferrous (Fe^2+) and ferric (Fe^3+) ions.
Ferrous ions have a +2 oxidation state, while ferric ions have a +3
oxidation state.
• Reaction with Acids:
• Iron reacts with various acids, such as hydrochloric acid (HCl) or sulfuric
acid (H₂SO₄), to produce hydrogen gas and the corresponding iron salts.
• For example​:
Fe+2HCl→FeCl2​+H2
• Complex Formation:
• Iron can form complex ions by interacting with ligands. This property is
often utilized in coordination chemistry.
• For instance, iron forms complexes with molecules like water, ammonia,
and cyanide.
• Redox Reactions:
• Iron participates in redox reactions, where it undergoes changes in oxidation
state.
• One example is the reaction between iron and copper(II) sulfate, where iron is
oxidized while copper is reduced:
Fe+CuSO4​→FeSO4​+Cu
• Solubility of Iron Salts:
• The solubility of iron salts can vary. For example, ferrous sulfate (FeSO₄) is
soluble in water, while ferric hydroxide (Fe(OH)₃) is insoluble and forms rust.
• Reaction with Carbon Monoxide:
• Iron can react with carbon monoxide to form iron carbonyl complexes, which
are important in certain industrial processes like the Mond process for nickel
refining.
• The reaction can be represented as:
Fe+5CO→Fe(CO)5​

• Catalytic Activity:
• Iron can act as a catalyst in various chemical reactions, such as the Haber-
Bosch process for ammonia synthesis and the Fischer-Tropsch synthesis for
the production of hydrocarbons.
• Electronic Configuration:
Iron has an atomic number of 26, meaning it has 26 electrons. The
electronic configuration of iron is [Ar] 3d^6 4s^2. The presence of
unpaired electrons in its outer electron shell contributes to its magnetic
properties, which are crucial in various electrical applications.
• Crystal Structure:
At room temperature, iron has a body-centered cubic (BCC) crystal
structure. This arrangement of atoms in a regular pattern contributes
to its electrical conductivity. The metallic lattice allows electrons to
move freely, carrying electric charge
Electrical properties

The electrical properties of iron are primarily influenced by its atomic and
crystalline structure, as well as its electronic configuration. The key factors
that contribute to the electrical properties of iron:
• Metallic Bonding:
Iron belongs to the group of metals, and like other metals, it has metallic bonding.
In metallic bonding, electrons are delocalized, meaning they are not bound to
specific atoms but are free to move throughout the metal lattice. This delocalized
electron sea allows for the efficient movement of electric charge, resulting in high
electrical conductivity.
Flow of current in iron
Iron consists of a lattice of atoms, each with an outer shell
of electrons that freely dissociate from their parent atoms
and travel through the lattice. This is also known as a
positive ionic lattice. This 'sea' of dissociable electrons
allows the metal to conduct electric current. When an
electrical potential difference (a voltage) is applied across
the metal, the resulting electric field causes electrons to
drift towards the positive terminal. The actual drift velocity
of electrons is typically small, on the order of magnitude of
m/hr. However, due to the sheer number of moving
electrons, even a slow drift velocity results in a large current
density. The mechanism is similar to transfer of momentum
of balls in a Newton's cradle but the rapid propagation of an
electric energy along a wire is not due to the mechanical
forces, but the propagation of an energy-carrying
electromagnetic field guided by the wire.
Magnetic properties

• Ferromagnetism:
• Iron is a ferromagnetic material, meaning it can be easily magnetized in
the presence of an external magnetic field. When exposed to a
magnetic field, the magnetic moments of individual iron atoms align in
the same direction, leading to the formation of magnetic domains.
These domains contribute to the overall magnetization of the material.
• Magnetic Domains:
• In its natural state, iron consists of numerous small regions
called magnetic domains. Within each domain, the magnetic
moments of the atoms are aligned. However, in the absence of
an external magnetic field, these domains are randomly
oriented, resulting in a net magnetization of zero for the entire
material.
• Alignment of Magnetic Moments:
When an external magnetic field is applied to iron, the magnetic moments
within the domains tend to align with the field. As the alignment progresses,
the magnetic domains grow in size, leading to an increase in the overall
magnetization of the iron.
• Saturation Magnetization:
Iron can reach a state of saturation magnetization, where nearly all magnetic
moments within the material are aligned with the applied magnetic field.
This saturation level depends on factors such as temperature and impurities.
• Retentivity and Coercivity:
• Retentivity (remnant magnetization) is the ability of iron to retain its
magnetization even after the removal of the external magnetic field.
Coercivity is the amount of magnetic field required to demagnetize the
material. Iron has relatively low coercivity, making it easy to magnetize and
demagnetize.
• Hysteresis:
• Iron exhibits hysteresis, which is the lag in the magnetization response when
the external magnetic field changes. Hysteresis in iron results in energy losses
in the form of heat, and it is a consideration in the design of magnetic
components like transformers and inductors.
• Temperature Dependence:
• The magnetic properties of iron are temperature-dependent. Above a certain
temperature called the Curie temperature (around 770 degrees Celsius for
pure iron), ferromagnetic materials lose their magnetization. At temperatures
above the Curie temperature, iron becomes paramagnetic, meaning it has a
weak attraction to an external magnetic field.
• Magnetic Permeability:
• Iron has a high magnetic permeability, which means it easily allows the flow
of magnetic flux. This property makes iron a preferred material for use in
magnetic circuits, such as in the cores of transformers and inductors.
Allotropes of Iron

Iron primarily exists in two allotropic forms at normal pressures and temperatures:
alpha iron (α-iron) and gamma iron (γ-iron).
Alpha Iron (α-iron):
At temperatures below 912 degrees Celsius (1,674 degrees Fahrenheit), iron exists
in the alpha phase, which has a body-centered cubic (BCC) crystal structure.
Alpha iron is stable at lower temperatures and undergoes a phase transition to
gamma iron at 912 degrees Celsius.
It is also known as ferrite and is a relatively soft and ductile form of iron.
• Gamma Iron (γ-iron):
At temperatures above 912 degrees Celsius (1,674 degrees Fahrenheit), iron
transforms into the gamma phase, which has a face-centered cubic (FCC) crystal
structure.
Gamma iron is stable at elevated temperatures and exhibits higher ductility
compared to alpha iron.
This allotrope is also known as austenite, and it is commonly found in high-
temperature applications, such as during the heating and processing of iron and
steel.
Classification of Iron

On basis of its composition, structure, and properties.

• Pure Iron:
Pure iron refers to iron that contains only the element itself and minimal
impurities. It is relatively soft and has limited industrial use. Most iron used
in various applications is not pure but is often alloyed with other elements.
• Wrought Iron:
Wrought iron is a type of iron with a very low carbon content (usually less
than 0.1%). It is characterized by its fibrous structure, high ductility, and
resistance to corrosion. Wrought iron was historically used for decorative and
ornamental purposes, as well as in the construction of bridges and buildings
• Cast Iron:
Cast iron is an iron-carbon alloy with a higher carbon content than wrought iron,
typically between 2% and 4%. It has excellent casting properties, high hardness,
and is brittle. Cast iron is commonly used in the construction of pipes, engine
blocks, and cookware.
• Steel:
Steel is an iron-carbon alloy with a carbon content typically ranging from 0.2% to
2%. It is one of the most widely used materials in the world due to its versatility,
strength, and formability. Various types of steel are produced by adjusting the
alloying elements and heat treatment processes.
• Alloy Steels:
Alloy steels are steel grades that contain additional alloying elements such as
chromium, nickel, manganese, or molybdenum. These elements are added to
enhance specific properties like hardness, corrosion resistance, or heat
resistance.
• Stainless Steel:
Stainless steel is a corrosion-resistant alloy of iron, chromium, and, in some
cases, other elements like nickel or manganese. It is known for its resistance to
rust and staining, making it suitable for applications in harsh environments,
such as kitchen appliances and chemical processing plants.
• Tool Steel:
Tool steels are specially designed to have high hardness, wear resistance,
and heat resistance. They are used in the production of cutting tools,
molds, and dies.
• Ductile Iron:
Ductile iron, also known as nodular cast iron or spheroidal graphite iron,
is a type of cast iron alloyed with small amounts of magnesium or cerium.
This results in a more ductile and less brittle material, making it suitable
for applications where toughness is essential.
 INTRODUCTION

Fiber optics deals with the light propagation through thin glass fibers. Fiber
optics plays an important role in the field of communication to transmit voice,
television
and digital data signals fro one place to another. The transmission of light along
the thin
cylindrical glass fiber by total internal reflection was first demonstrated by John
Tyndall
in 1870 and the application of this phenomenon in the field of communication is
tried
only from 1927. Today the applications of fiber optics are also extended to medical
field in the form of endoscopes and to instrumentation engineering in the form of
optical
General Properties

Structure of Optical fiber

The optical fiber mainly consists the following six parts as shown in figure
Core
A typical glass fiber consists of a central core material. Generally core
diameter is
50. The core is surrounded by cladding. The core medium refractive is always
greater than the cladding refractive index.

Cladding

Cladding refractive index is lesser than the cores refractive index. The over
alldiameter of cladding is 125 to 200.

Silicon Coating

Silicon coating is provided between buffer jacket and cladding. It improves the
quality of transmission of light.

Buffer Jacket

Silicon coating is surrounded by buffer jacket. Buffer jacket is made of plastic

Strength Member

Buffer jacket is surrounded by strength member. It provides strength to the fiber cable.

Outer Jacket

Finally the fiber cable is covered by polyurethane outer jacket. Because of this
arrangement fiber cable will not be damaged during pulling, bending, stretching and
rolling through the fiber cable is made up of glasses.
 ELECTRICAL PROPERTIES
Optical fibers are primarily used for transmitting light signals over long distances with
minimal loss. However, they also possess certain electrical properties, though they are not
the primary focus of their functionality. Here are some electrical properties of optical fibers:
• Resistance: Optical fibers have a very low resistance to electrical current flow. This is
because they are typically made of materials like silica glass or plastic, which are
insulators and do not conduct electricity. Therefore, they are not used to transmit
electrical signals directly.
• Dielectric constant: The dielectric constant of the materials used in optical fibers affects
their capacitance and impedance characteristics. Higher dielectric constants can lead to
higher capacitance, which may affect signal transmission in certain applications.
• Inductance: While optical fibers themselves do not exhibit inductance, they may be
bundled with electrical conductors within a cable assembly. The presence of conductors
can introduce inductance, which may affect the overall electrical performance of the
cable.
• EMI/RFI Immunity: One of the advantages of optical fibers over electrical conductors is
their immunity to electromagnetic interference (EMI) and radio frequency interference
(RFI). This is because they do not conduct electrical signals and are not affected by
 • Lightnening Protection
Optical fiber cables are not susceptible to damage from lightning strikes in the same way that
electrical conductors are. This makes them advantageous in outdoor and high-risk environments
where lightning protection is a concern
• Grounding:
While optical fibers do not require grounding for electrical purposes, grounding may still be
necessary for safety reasons, such as to prevent static buildup or to ensure proper equipment
bonding in a telecommunications or data networking installation.
 Working
Principle
The basic principle of optical fiber in the transmission of optical signal is total internal
reflection
Total Internal Reflection
When the light ray travels from denser medium to rarer medium the refracted ray
bends away from the normal. When the angle of incidence is greater than the critical
angle, the refracted ray again reflectsinto the same medium. This phenomenon is called
total internal reflection.

The refracted ray bends towards the normal as the ray travels from rarer medium to
denser medium. The refracted ray bends away from the normal as it travels from denser
medium to rarer medium.
 When the angle of incidence is greater than the critical angle (i > qC ), the refracted ray
again reflects into the same medium. This phenomenon is called total internal reflection

When (i < qC ) , then the ray refracts into the secondary medium
When (i = qC ), then the ray travelsalong the interface
When (i > qC ), then the ray totally reflects back into the same medium
Classification of fibers:-

Based on the refractive index of core medium, opticalfibers are classified into two
categories.
i. Step index fiber
ii.Graded index fiber

Based on the number of modes of transmission, optical fibers are classified into two
categories
i.Single mode fiber
ii.Multi mode fiber

Based on the materialused, optical fibers are may broadly classifiedinto four categories
i.All glass fibers
ii.All plastic fibers
iii.Glass core with plastic cladding fibers
iv.Polymer clad silica fibers.
Optical fiber communication system:-
Receiver
An optical fibercommunication system mainlyconsists of the following
parts as shown in figure.
• 1.Encoder
• 2.Transmitter
• 3.Wave guide.
• 4.Receiver.
• 5.Decoder
Applications of optical fibers

• Optical fibers are extensively used in communication system.

• Optical fibers are in exchangeof information between different computers
• Optical fibers are used for exchangeof information in cable televisions, space vehicles,
submarines etc.
• Optical fibers are used in industry in security alarm systems, process control and
industrial auto machine.
• Optical fibers are used in pressuresensors in biomedical and engine control.
• Optical fibersare used in medicine, in the fabrication in endoscopy for the
visualization of internal parts of the human body.
• Sensing applications of optical fibers are Displacement sensor
• Fluid level detector Liquid level sensor
• Temperature and pressure sensor Chemical sensors
Medical applications of optical fibers are Gastroscope
• Orthoscope Couldoscope Peritonescope Fiberscope