2. CONTENTS
What is characterization of materials?
What is its significance?
Techniques of characterization.
Description
comparison
References
2
3. What is characterization of
materials?
Characterization , refers to the process by which a
material's structure and properties are determined
It is a fundamental process, without which no scientific
understanding of engineering materials could be
established
3
4. What is its significance?
It helps to increase the different degree of understanding
of materials showing different properties and behavior
Also, it helps to analyze and optimize the materials
4
5. Techniques of characterization.
There are several techniques of characterization for testing
various properties of material such as-
•Microscopy techniques
•Spectroscopy techniques
•Macroscopic techniques
5
6. Scanning Electron Microscope (SEM)
Microscope that produces images of
sample by scanning the surface with
focused beam of electrons
Produces various signal that reveals
the information about surface
composition and topography
Can produce very high resolution
images of sample surface
6
8. Surface of a kidney stone
Normal circulating human blood
(red blood cells)
Depth hoar snow crystal, viewed through light
microscope (left) and as an SEM image (right)
8
9. Application
1. Topographical, morphological and compositional information
2. Provides information in microstructure
3. Examine surface contaminations
4. Gives qualitative chemical analysis
5. Identify crystalline structures
9
10. Advantages Disadvantages
Detailed 3D and topographical imaging Expensive, large ( installed in area free
of electric, magnetic or vibration
interference
Easy to operate and user friendly High maintenance
Fast working Limited to solid, inorganic samples small
enough to fit inside vacuum chamber
Modern technology allow for generation
of digital data
Small risk of radiation exposure
SEM samples require minimal
preparation actions
Advantages & Disadvantages of SEM
10
15. Advantages Disadvantages:
Offers most powerful magnification Large and expensive
Provide information on element and
compound structure
Require special training
High quality and detailed images Samples are limited to those that
are electron transparent, able to
tolerate vacuum chamber and small
enough to fill in the chamber
Able to yield information of surface
features, shape, size and structure
Special housing and maintenance
Easy to operate Images are black and white
Advantages & Disadvantages of TEM
15
16. SEM TEM
1. SEM is based on scattered electrons TEM is based on transmitted electrons
Comparison b/w SEM & TEM
16
17. 2. SEM focuses on the sample’s surface
and its composition
TEM provides the details about internal
composition
17
19. 4. provides a 3-dimensional image provides a 2-dimensional picture
19
20. 8. picture is shown on monitor pictures are shown on fluorescent screens
5. there is no need of cutting thinner
sample
The sample has to be cut thinner
6. allows for large amount of sample to be
analyzed at a time
only small amount of sample can be
analyzed at a time
7. SEM is used for surfaces, powders,
polished & etched microstructures, IC
chips, chemical segregation
is used for imaging of dislocations, tiny
precipitates, grain boundaries and other
defect structures in solids
20
