This document discusses material characterization testing techniques. It focuses on scanning electron microscopy (SEM) as one such technique. It provides an introduction to SEM, explaining that it produces images using a focused electron beam interacting with sample atoms. The principles of SEM are described. Sample preparation requirements are outlined, such as size, vacuum compatibility, and mounting. The document then describes the specimen loading, vacuum creation, magnification, and microstructure examination processes involved in SEM.

1. M.KARTHIKEYAN
ASSISTANT PROFESSOR
DEPARTMENT OF MECHANICAL ENGINEERING
AAA COLLEGE OF ENGINEERING & TECHNOLOGY, SIVAKASI
karthikeyan@aaacet.ac.in
OML751 TESTING OF MATERIALS

2. UNIT IV MATERIAL CHARACTERIZATION TESTING
1. Macroscopic observations
2. Microscopic observations
3. Optical microscopy
4. Electron microscopy (SEM)
5. Electron microscopy (TEM)
6. Diffraction techniques,
7. Spectroscopic Techniques,
8. Electrical Techniques
9. Magnetic Techniques
Principles, Types, Advantages and Limitations, Applications.

4. ELECTRON MICROSCOPY (SEM)
SCANNING ELECTRON MICROSCOPY
INTRODUCTION:
 A scanning electron microscope (SEM) is a type of electron
microscope.
 It produces images of a sample by scanning the surface with a
focused beam of electrons.
PRINCIPLE:
 The electrons interact with atoms in the sample, producing
various signals that contain information about the
surface topography and composition of the sample.

5. SAMPLE PREPARATION:
 SEM samples have to be small enough to fit on the specimen
stage.
 samples should have the capability to withstand the high
vacuum conditions and the high energy beam of electrons.
 Samples are generally mounted rigidly on a specimen holder or
stub using a conductive adhesive.

6. SPECIMEN LOADING

7. VACUUM CREATION

8. MAGNIFICATION

9. EXAMINATION OF MICROSTRUCTURE