U5 PART A.docx

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Course Code & Name: CME397 Surface Engineering
Branch/ Semester: Mechanical Engineering/VI Semester
Course Instructor Name & Department: M.Karthikeyan, Assistant Professor/Mech
1. Enumerate the applications of nanotribology [UN, CO5]
1. Precision Engineering: Nanotribology helps in
understanding friction, wear, and lubrication at
the nanoscale.
It is important for designing precise and durable
mechanical components such as micro-electromechanical
systems (MEMS) and nano-electromechanical systems
(NEMS).
2. Material Science: It helps in developing advanced
materials with enhanced friction and wear
properties, benefiting industries like aerospace,
automotive, and biomedical engineering by improving
the performance and lifespan of components.
2. Discuss the materials used for prosthetics [RE, CO5]
Materials used for prosthetics include:
1. Titanium: Known for its strength, durability, and
biocompatibility, titanium is often used in
prosthetic components such as joint replacements
and bone implants.
2. Carbon Fiber: Lightweight and strong, carbon fiber
is utilized in prosthetic limbs.
3. What are the materials used for implants [RE, CO5]
Materials used for implants include:
1. Titanium: Due to its excellent biocompatibility,
corrosion resistance, and strength, titanium is widely
used in various implants such as dental implants,
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Unit 5 – Part A

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joint replacements, and bone fixation plates.
2. Ceramics: Materials like alumina and zirconia are
used in dental and orthopedic implants due to
their biocompatibility, wear resistance, and ability to
mimic natural bone structure.
4. List out the examples for low friction materials [RE, CO5]
1. Polytetrafluoroethylene (PTFE): Commonly known
as Teflon, PTFE exhibits excellent lubricating
properties due to its low friction coefficient, making it
suitable for various applications including coatings,
seals, and bearings.
2. Molybdenum Disulfide (MoS2): This solid lubricant
has a lamellar structure that reduces friction
between surfaces, making it useful in applications
such as automotive lubricants, aerospace
components, and manufacturing machinery.
5. List out the examples for high friction materials [RE, CO5]
1. Rubber: Due to its high coefficient of friction, rubber
is often used in applications where grip and traction
are important, such as tires, conveyor belts, and
shoe soles.
2. Brake Pads: Materials like semi-metallic compounds
or ceramics are used in brake pads to create high
friction when pressed against a rotor, allowing for
effective braking in automotive and industrial
applications.
6. Enumerate the types of ceramic oxides [RE, CO5]
• Alumina (Aluminum Oxide, Al2O3)
• Boron trioxide
• Zirconia (Zirconium Dioxide, ZrO2)
• Silica (Silicon Dioxide, SiO2)
• Magnesia (Magnesium Oxide, MgO)

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• Titanium Dioxide (TiO2)
• Ferric Oxide (Iron(III) Oxide, Fe2O3)
• Calcium Oxide (Quicklime, CaO)
• Beryllia (Beryllium Oxide, BeO)
• Tin Oxide (SnO2)
7. Enumerate the examples for Biomaterials [RE, CO5]
1. Hydroxyapatite: This calcium phosphate compound
is found naturally in bone and teeth and is
commonly used as a coating for implants to promote
osseointegration.
2. Collagen: A protein found in connective tissues,
collagen is used in various biomaterial applications
such as wound dressings, tissue engineering
scaffolds, and drug delivery systems.
8. What is Biomaterial? [RE, CO5]
A biomaterial is any substance that has been engineered
to interact with biological systems for medical
purposes, such as treating, repairing, or replacing
tissues, organs, or functions of the body.
9. Define Tribology [RE, CO5]
Tribology is the study of friction, wear, and lubrication.
10. Define Nano Tribology [RE, CO5]
Nanotribology is the study of friction, wear, and
lubrication at nanoscale.

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1. List out the examples for prosthetics. [RE, CO5]
1. Prosthetic Limbs: Artificial limbs designed to
replace lost or missing body parts, such as arms,
legs, hands, or feet.
2. Dental Implants: Tooth replacements used to
restore the function and appearance of missing teeth,
often made of materials like titanium or ceramics.
2. List out the various implants. [RE, CO5]
1. Dental Implants: Used to replace missing teeth and
provide support for dental prostheses like crowns,
bridges, or dentures.
2. Orthopedic Implants: These include joint
replacements (such as hip or knee replacements),
bone plates, screws, and pins used to stabilize
fractures or replace damaged joints.
3. Enumerate the clinical reasons to remove the implants [UN, CO5]
(1) infection
(2) fracture
(3) wear and
(4) loosening.
Among these, fracture wear and loosening related to
biotribological reactions.
4. What are the essential characteristics of a biomaterial? [RE, CO5]
Bio compatibility
Non toxic
Non corrosive
Excellent strength
5. What are superalloys [RE, CO5]
Superalloys are high-performance materials designed to
withstand extreme temperatures and mechanical
stresses, commonly used in aerospace, gas turbine

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engines, and other demanding applications.
6. Name the materials used as a filler in teeth [RE, CO5]
Materials used as a filler in teeth include:
1. Dental Amalgam: A mixture of metals (usually
silver, tin, copper, and mercury) that has been used
for over a century to fill cavities in teeth.
2. Composite Resin: A tooth-colored material
composed of glass or quartz filler particles suspended
in a resin matrix, used for aesthetic dental fillings.
7. Name the materials used for teeth implant [RE, CO5]
Materials used for teeth implants include:
1. Titanium: Widely used due to its biocompatibility
and ability to integrate with bone tissue, providing a
strong foundation for dental implants.
2. Zirconia: Recognized for its biocompatibility and
tooth-like appearance, zirconia implants are
increasingly popular, especially for patients
concerned about metal allergies or aesthetics.
8. Name the various studies involved in nanotribology [RE, CO5]
• atomic-scale interactions,
• surface roughness,
• molecular dynamics, and
• nanoscale wear mechanisms.
9. Define the term implants [RE, CO5]
Implants are artificial devices or materials surgically
inserted into the body to replace missing biological
structures, support damaged tissues, or enhance bodily
functions.
10. Define the term prosthetics [RE, CO5]
A prosthesis is a device designed to replace a missing part

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of the body or to make a part of the body work better.