Ans1.

• Engineering Materials : Materials to which concepts of science,

Technology are applied and converted to useful products, helps
to satisfy our needs, improve our life style, comfort……
• Have some commercial value/ importance (because engineering
is performed with this material, improves its usefulness, fulfill
our needs).

Here are explanatory notes on some common engineering materials:

Metals:
Properties: Metals are characterized by high strength, ductility, thermal and
electrical conductivity.
Applications: Structural components, electrical conductors, heat exchangers.
Types: Ferrous (iron-based - steel, cast iron) and non-ferrous (aluminum,
copper, brass).

Polymers:
Properties: Polymers are lightweight, have low density, and are excellent
insulators.
Applications: Plastics, rubbers, fibers used in packaging, automotive parts,
and insulating materials.
Types: Thermoplastics (can be melted and re-molded) and thermosetting (retain
shape after curing).

Ceramics:
Properties: Ceramics are hard, brittle, and have high-temperature stability.
Applications: Structural components, electronic components, insulators.
Types: Oxides, nitrides, carbides.

Composites:
Properties: Composites are a combination of two or more materials to obtain
unique properties.
Applications: Aircraft components, sporting goods, automotive parts.
Types: Fiber-reinforced composites, particle-reinforced composites.

Semiconductors:
Properties: Semiconductors have intermediate conductivity, crucial in
electronics.
Applications: Integrated circuits, transistors, diodes.
Examples: Silicon, germanium.

Fluids:
Properties: Fluids include liquids and gases.
Applications: Hydraulic systems, cooling systems, lubrication.
Types: Water, hydraulic fluids, air.

Ans2.

The "Structure-Properties-Uses" relationship is a fundamental concept in materials

science and engineering.
It describes the interdependence between the internal structure of a material, its
resulting properties, and how these properties influence its practical applications
or uses.This relationship is crucial because it guides engineers and material
scientists in selecting the most appropriate materials for specific applications
based on desired performance criteria.

Let's break down the significance of each component in this relationship:

Structure:
The internal arrangement of atoms, molecules, or crystals in a material.
Different materials have distinct structures, such as crystalline, amorphous, or
composite structures.

Properties:
The physical, mechanical, thermal, electrical, and chemical characteristics of a
material.
Properties are influenced by the material's structure and composition.
Examples include hardness, strength, conductivity, thermal expansion, etc.

Uses (Applications):
The practical applications or functions for which a material is employed.
Materials are chosen based on their properties to meet specific engineering
requirements.
Examples include structural components, electrical conductors, insulators, thermal
barriers, etc.

Example - Steel:
Structure:
Steel is an alloy of iron and carbon, often with other alloying elements. The
carbon atoms are interstitially positioned in the iron lattice, forming a strong
crystalline structure.

Properties:
High strength, durability, and ductility.
Excellent thermal conductivity.
Magnetic properties.
Resistance to corrosion when alloyed with elements like chromium.

Uses:
Structural components in buildings, bridges, and infrastructure due to its high
strength.
Automotive industry for the production of chassis and body parts.
Cutlery and tools due to hardness and sharpness.
Magnetic applications in transformers and electric motors.

Significance:

Material Selection: Engineers can choose materials based on the required properties
for a specific application. For instance, in building construction, high-strength
materials like steel are chosen for load-bearing structures.
Performance Optimization: Understanding the structure allows engineers to
manipulate materials to enhance specific properties. Alloying, heat treatment, or
other processes can optimize performance.
Failure Analysis: When materials fail in service, understanding the structure-
properties relationship aids in identifying the root cause of failure and devising
preventive measures.
Innovation: Engineers can develop new materials with tailored properties for novel
applications by manipulating the material's structure.
Cost Efficiency: Choosing materials with the right properties for a given
application ensures cost-effective solutions and minimizes the risk of material
failure.

Ans3.

(from Ans1)

Ans4.
Composite materials are engineered materials composed of two or more distinct
phases with significantly different physical or chemical properties. These
materials are designed to combine the desirable characteristics of each constituent
phase, resulting in a material with improved overall performance. The components of
a composite material are typically referred to as the matrix and the reinforcement.

Classification of Composite Materials:

1. FRC – Fiber Reinforced Composites

Tyres are made of nylon fibers/ steel fibers embedded in
Rubber to improve overall strength, durability, life, safety (user
satisfaction) of tyres.
2. LRC – Laminated Reinforced Composites
Your 12th class mark sheet paper is laminated with plastic film
to improve its overall properties (required) .
Wind shields of car, Bullet proof glass etc…..
Dr. Dheeraj Mandloi 18
3. PRC – Particulate Reinforced Composite
SiC refractory + W metal = Cermets, Super Refractories

Advantages and Usefulness in Modern Technologies:

-High Strength-to-Weight Ratio

-Corrosion Resistance
-Design Flexibility
-Electrical and Thermal Insulation
-durability
-cost-Efficient

Ans5.

Material Testing
• Material testing is done to evaluate various properties of the
material, performance of the material, uses of the material,
capabilities.
Informations obtained from Material testing-
1. Identification of unknown material .[ Qualitative Testing]
2. Quantification, amount, how much.[ Quantitative Testing]
3. Analyses of Mixtures. [Both Qualitative and Quantitative]
4. Impurities/ defects / flaws (often present, affecting properties
of material)
Sources of impurities/ defects -
Natural, during handling, deliberately added
5. Tolerance limit / permissible limit
But who will guide us regarding these limits (for effective use)
Some standard agencies like
-ASTM (American Society for Testing and Materials)
-BIS (Bureau of Indian Standards)

Ans6.

Classification of Material Testing:

Different Material Testing methods provides different type of
information.
Very big class, various types of material testing procedures, so
classification is essentially required.
Each type of classification have its own importance.

I. On the basis of methodology:

1. Physical testing: Glass slab, prism, density, mp, bp, weight
etc…..
2. Chemical testing: Titration, organic functional group test etc…
Both these testing methods are very old but still very much useful,
in practice
3. Instrumental methods: combination of above using
sophisticated instruments, electronics, computers, softwares
Eg. pH meter, Spectroscopy etc.

II. On the basis of nature of information obtained:

1. Qualitative testing: identification, quality……
Functional group test,Litmus paper test etc.
2. Quantitative testing: quantity, amount……
Titration, Viscosity of oil, pH value, %C in steel etc

III. On the basis of what happens with the sample:

1. Destructive test: sample gets destroyed during/after testing
(looses its properties, usefulness) and can not be used again.
Eg. Water hardness determination by EDTA titration etc.
Destructive tests are usually slow, tedious, sample gets destroyed,
uneconomical for costly samples
2. Non-Destructive test (NDT): sample retains its properties and
can be used again after testing.
Eg. pH determination by digital pH meter, Viscosity of oil etc

IV. On the basis of testing environment:

1. Laboratory test: Test performed under standard, well
defined, well documented (ASTM, BIS) set of
conditions.
2. Field test: Test performed under practical, real world
conditions. User have no/very less control over testing
conditions.
Used to know performance of sample in real world,
practical conditions.

Ans7.

A refractory material is a type of material that possesses high resistance to heat

and thermal stress, making it suitable for use in environments with extreme
temperatures and conditions. These materials are designed to withstand intense
heat, corrosion, and mechanical wear, making them essential in applications where
other materials would degrade or fail under such conditions.

Furnaces and Kilns:

Refractories are extensively used in the construction of furnaces and kilns in
industries such as steel, glass, ceramics, and cement manufacturing. These
materials line the interior of these units to withstand the extreme temperatures
generated during various processes.

Power Plants:
Refractory materials are employed in the construction of boilers, incinerators, and
other high-temperature equipment in power plants.

Glass Industry:
Glassmaking involves high temperatures, and refractory materials are used to line
the melting furnaces and other equipment in the glass industry.

Ceramics Industry:
Kilns used in the production of ceramics and pottery are lined with refractory
materials to withstand the heat required for the firing process.

Space Exploration:
Refractories are used in the construction of spacecraft heat shields and components
that need to withstand the intense heat during atmospheric re-entry.

Automotive Industry:
Refractories are used in the manufacturing of catalytic converters and other
components in the automotive industry that are exposed to high temperatures.

High-Temperature Laboratories:
Research facilities and laboratories involved in high-temperature experiments use
refractory materials to construct furnaces and equipment.

Ans8.

Characteristics/ Properties of Refractory

1. Temp tolerance should be more than working temperature,determined using Seger

Cone test
2. should also resist load of the surroundings .
3. should not chemically react with surroundings.
4. should have high resistance to abrasion.
5. should expand and contract minimum and uniform with rise and fall in temp .
6. should resist cracking, breaking and fracturing during working.
7. Should have minimum porosity .

ANS9.

Classification of REFRACTORY
I. On the basis of temp toleranceLow heat duty, moderate heat duty, high heat
duty,
super high heat duty.
II. On the basis of Chemical nature
1. Acidic refractory- Fire clay, silica, alumina etc.
2. Basic refractory- Dolomoite, Magnesia etc.
3. Neutral refractory- SiC, Chromite, Zirconia etc.

ANS10.

Portland Cement:

Definition: Portland cement is a hydraulic cementitious material composed of finely

ground clinker, mixed with a small amount of gypsum to control the setting time. It
is the key ingredient in concrete and is used as a binder in the construction
industry.
Composition: The primary components of Portland cement are clinker (calcined
limestone and clay), gypsum, and small amounts of other additives.
Properties: It hardens and gains strength over time through a chemical reaction
known as hydration. It forms the basis for making concrete and mortar.

Concrete:
Definition: Concrete is a composite material composed of aggregates (such as sand
and gravel), cement (usually Portland cement), and water. It is a versatile
construction material that can be shaped and molded into various forms.
Composition: Concrete consists of a mixture of cement, aggregates (sand and gravel
or crushed stone), water, and, sometimes, additional additives or admixtures.
Properties: When mixed, poured, and cured, concrete hardens and forms a durable
structure. Its properties can be adjusted by varying the proportions of its
components.

Mortar:
Definition: Mortar is a workable paste used to bind building blocks, such as
bricks, stones, or concrete masonry units, together. It is a mixture of cement,
fine aggregates, and water.
Composition: Mortar typically contains Portland cement, sand, and water. The ratio
of cement to sand determines the strength and workability of the mortar.
Properties: Mortar provides a strong bond between masonry units, creating a
cohesive structure. It is applied in layers to secure and stabilize building
elements.

Reinforced Concrete (RCC):

Definition: Reinforced Concrete (RCC) is a type of concrete in which steel
reinforcement (rebar) is embedded to enhance its tensile strength. The combination
of concrete's compressive strength and steel's tensile strength results in a
versatile and strong building material.
Composition: RCC consists of concrete, typically made with Portland cement, and
embedded steel reinforcement in the form of bars or mesh.
Properties: RCC combines the compressive strength of concrete with the tensile
strength of steel, resulting in a material suitable for a wide range of structural
applications. It is commonly used in building construction, bridges, dams, and
other infrastructure.

Differentiation:

Application:
Portland Cement: Used as a binder in concrete and mortar.
Concrete: Used as a building material for structures.
Mortar: Used for binding masonry units.
RCC: Used in structural applications where both compressive and tensile strength
are required.

Composition:
Portland Cement: Mainly clinker and gypsum.
Concrete: Mixture of cement, aggregates, water, and additives.
Mortar: Mixture of cement, sand, and water.
RCC: Combination of concrete and embedded steel reinforcement.

Purpose:
Portland Cement: Provides the binding property in concrete and mortar.
Concrete: Used for structural construction.
Mortar: Binds masonry units.
RCC: Combines strength and durability for structural applications.

ANS11.
ANS12.

High Silica Cement:

Composition: High Silica Cement, also known as Silicate Cement, contains a higher
percentage of silica (SiO2) than other types of cement. It typically has low lime
content and is made by fusing silica with bauxite or similar materials.
Properties:
High resistance to chemical attacks.
Low heat of hydration.
Suitable for refractory applications.
Uses:
Primarily used for making refractory bricks for furnaces and kilns.
Used in construction projects where resistance to chemical attack is crucial.
High Alumina Cement:

Composition: High Alumina Cement, or Calcium Aluminate Cement, is made by fusing

bauxite and limestone. It contains a high percentage of alumina (Al2O3).
Properties:
Rapid hardening and setting.
High early strength.
Resistant to sulfate attacks.
Uses:
Suitable for rapid construction projects.
Used in marine environments and sewage treatment plants.
High-temperature applications, such as in the construction of chimneys and
industrial furnaces.
White Cement:

Composition: White Cement is similar to Portland cement but contains a lower amount
of iron oxide and manganese. The color is achieved by using raw materials with low
iron content.
Properties:
White color allows for a range of aesthetic finishes.
Similar strength properties to ordinary Portland cement.
Uses:
Decorative and architectural applications.
Used when a light-colored finish is desired, such as in precast concrete elements,
tiles, and architectural concrete.
Suitable for coloring with pigments to achieve various shades.
Differentiation:

Composition:

High Silica Cement: High silica content, low lime content.

High Alumina Cement: High alumina content, fusing bauxite and limestone.
White Cement: Low iron oxide content, similar to Portland cement.
Properties:
High Silica Cement: Resistant to chemical attacks, low heat of hydration.
High Alumina Cement: Rapid hardening, high early strength, sulfate-resistant.
White Cement: White color for decorative finishes, similar strength to Portland
cement.
Uses:

High Silica Cement: Refractory applications, resistance to chemical attacks.

High Alumina Cement: Rapid construction, sulfate-resistant applications, high-
temperature environments.
White Cement: Aesthetic finishes, architectural and decorative applications,
coloring options.

ANS13.

1. Mixing of Raw materials- Dry or Wet mixing in required composition (BIS code) to
get slurry.

2. Burning in Rotary Kiln- most important, sensitive, longest step.

Heating zone- gradual heating of slurry
Calcination zone- CaCO3 converted to CaO
Clinker zone- actual chemical reactions between lime, silica and alumina forming
mixture of Calcium silicates and Calcium aluminates as C3S, C2S, C3A, C4AF as
solidified balls (clinkers).

3. Collection, cooling and grinding of clinkers and addition of Gypsum- Now cement
is ready.

4. Testing of Cement- quality check as per BIS Physical testing- fineness,

soundness, initial and final setting time.
Chemical testing- to check chemical composition as per BIS.
Mechanical testing- hardness, abrasion resistance, strength.

ANS14.

Setting and Hardening of Cement

SETTING is stiffening of original concrete paste due to initial gel
formation followed by crystallization. This is due to fast hydration
reaction between C3A, C4AF with water resulting in initial strength
and hardness. Completed within few hours. (pin test). Followed by
hardening.

HARDENING is gradual development of strength and hardness. This

is due to slow hydration reaction between C2S, C3S with water
resulting in formation of crystalline products. Almost completed
within 28 days, so curing must continue up to 28 days. There is
very strong interlocking between theses crystalline products
resulting in very hard, strong, rigid, compact, high load tolerable,
durable structures.
ANS15

Polymers:
Polymers are large molecules composed of repeating structural units called
monomers. These long-chain molecules have high molecular weights and exhibit unique
properties due to their structure. Polymers play a crucial role in various
industries, providing materials with diverse properties and applications.

Three Commercially Useful Polymers:

Polyethylene (PE):
Properties:
Structure: Linear, high molecular weight hydrocarbon chain.
Types: High-Density Polyethylene (HDPE), Low-Density Polyethylene
(LDPE).
Properties: Lightweight, chemically resistant, excellent electrical
insulator.
Uses:
HDPE: Packaging materials, containers, pipes.
LDPE: Plastic bags, films, squeeze bottles.

Polyvinyl Chloride (PVC):

Properties:
Structure: Repeating units of vinyl chloride.
Properties: Versatile, durable, resistant to chemicals and
weathering.
Types: Rigid PVC (uPVC) and Flexible PVC.
Uses:
Rigid PVC: Construction pipes, window frames, electrical conduits.
Flexible PVC: Hoses, inflatable structures, cable insulation.

Polyethylene Terephthalate (PET):

Properties:
Structure: Repeating units of ethylene glycol and terephthalic acid.
Properties: Transparent, lightweight, strong, excellent gas barrier.
Uses:
Packaging: PET bottles for beverages, food containers.
Textiles: Polyester fibers for clothing, carpets.

ANS16.

Glass:
Glass is a solid material that exhibits a non-crystalline, amorphous structure. It
is commonly produced by melting raw materials such as silica, soda ash, and
limestone, and then cooling the molten mass rapidly to prevent crystallization.
Glass is known for its transparency, hardness, and brittleness.
1]Soda-Lime Glass:

Composition: It is the most common type of glass and consists of silica (sand),
soda ash (sodium carbonate), and limestone.
Properties:
-Transparent and colorless (or slightly greenish).
-Economical and widely used in windows, bottles, and containers.
-Softens at a relatively low temperature.
Applications: Bottles, containers, windows, and common glassware.

2]Lead Glass (Lead Crystal):

Composition: It includes a significant amount of lead oxide (PbO) which enhances

its optical properties.
Properties:
-High refractive index, brilliance, and sparkle.
-Heavier and more resonant than soda-lime glass.
Applications: Fine glassware, decorative items, chandeliers, and jewelry.

3]Tempered Glass:

Production: It undergoes a controlled thermal or chemical treatment to increase its

strength compared to normal glass.
Properties:
-Increased strength and impact resistance.
-When broken, it shatters into small, less harmful pieces.
Applications: Automobile windows, shower doors, safety glass for building windows.