1. Course Title: Automotive Tribology
Course Code: AUT 518b
Cr. Hours 3
Prerequisites : Fluid Mechanics, solid Mechanics , Material science
Target group: MSc 2nd year Automotive Technology Student
Semester I
Academic Year 2023/24
Periods : Monday Morning 8:00-12:00
Venue: Room_6
Instructor: Hailemariam N. (Ph.D.)
COURSE OUTLINE
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2. 2.Friction and Wear Nature of metal surfaces
2.1.Introduction to Solid Surface
Characterization
2.2. Friction
2.3. wear and wear mechanism
Deliverables
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4. 2.1. Introduction to Solid Surface Characterization
Three phases of matter:
• Solids
• Liquids
• Gases.
• Surface is the physical boundary of only one of these
phases, such as solid surface, liquid surface etc.
• A surface is made by a sudden termination of the
bulk structure. The bonding that was
involved in the bulk lattice is severed to produce the
interface.
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6. 2.1. Introduction to Solid Surface Characterization
A solid surface, (a solid-gas or solid-liquid interface)
has a complex structure and complex properties
dependent upon:
• Nature of solids,
• Method of surface preparation,
• Interaction b/n the surface and the environment.
• It is the surface which interfaces with its
environment, and the surface reactivity will
determine how well the material behavior in its
intended function. 6
7. 2.1. Introduction to Solid Surface Characterization
Many of the surfaces are chemically reactive:
• Chemical corrosion film (surface oxide layers or
other layers nitrides, sulfides and chlorides) in
the air.
• Adsorbed films that are produced either by
physisorption or chemisorptions of oxygen,
water vapor, & hydrocarbons from environment.
• The presence of surface films (greasy or oily film)
affect friction and wear.
• These films are worn out in the initial period of
running and subsequently have no effect. 7
8. 2.1. Introduction to Solid Surface Characterization
Characterization:
• The word describes those features of
composition and structure (including defects) of
a material that are significant for a particular
preparation, study of properties, or use, and
suffice for reproduction of the material.
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9. 2.1. Introduction to Solid Surface Characterization
• Solid surfaces (irrespective of the method of formation)
contain deviations or irregularities from the prescribed
geometrical form (Surface texture)
• solid surface itself consists of several zones having
physicochemical properties peculiar to the bulk material
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10. 2.1. Introduction to Solid Surface Characterization
Surface texture:
• The surfaces contain irregularities of various orders
ranging from shape deviations to irregularities of the
order of interatomic distances
• Surface texture is the repetitive / random deviation
from the normal surface Components of surface texture
(roughness, waviness and error of form
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11. 2.1. Introduction to Solid Surface Characterization
(a) Surface roughness (Nano-and micro-roughness)
• Formed by fluctuations in the surface of short
wavelengths
• characterized by hills & valleys of varying amplitudes
b) Waviness (macro roughness)
• Formed by fluctuations in the surface of longer
wavelengths
• may result from such factors as machine or work piece
deflections, vibration, heat treatment etc.
c) Error of form
• a gross deviations from nominal shape of very long
wavelength 11
13. 2.1. Introduction to Solid Surface Characterization
SEM :
• SEM is a type of electron microscope that images the
sample surface by scanning it with a high-energy beam
of electrons in a raster scan pattern.
• Three different imaging modes: secondary electrons
(low energy electrons from the surface of the material),
backscattered electrons (more from bulk) and x-rays
(from near-surface region).
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23. Reference books :
Reference Book:
1. Surface Analysis Methods in Material Science
• Edited by D.J. O’Connor, B.A. Sexton, R.St.C.
Smart (Springer, 1992)
2. An Introduction to Surface Analysis by XPS and
AES
• John F. Watts and John Wolstenholme (John
Wiley & Sons, 2003)
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