Page 155 - Materials Science and Engineering An Introduction

4.10 Microscopic Techniques • 127

Dimensions of structural feature (m)
10 14 10 12 10 10 10 8 10 6 10 4 10 2
Subatomic particles

Atom/ion diameters
Unit cell edge lengths

Dislocations (width)
Second phase particles

Grains
Macrostructural features
(porosity, voids, cracks)
10 6 10 4 10 2 1 10 2 10 4 10 6 10 8
Dimensions of structural feature (nm)
(a)

Useful resolution ranges (m)
10 12 10 10 10 8 10 6 10 4 10 2 1
Scanning probe microscopes

Transmission electron microscopes
Scanning electron microscopes

Optical microscopes

Naked eye
10 2 1 10 2 10 4 10 6 10 8
Useful resolution ranges (nm)
(b)
Figure 4.16 (a) Bar chart showing size ranges for several structural features found in materials. (b) Bar chart
showing the useful resolution ranges for four microscopic techniques discussed in this chapter, in addition to the
naked eye.
(Courtesy of Prof. Sidnei Paciornik, DCMM PUC-Rio, Rio de Janeiro, Brazil, and Prof. Carlos Pérez Bergmann, Federal
University of Rio Grande do Sul, Porto Alegre, Brazil.)

to and stored in a computer, which then generates the three-dimensional surface
image.
These new SPMs, which allow examination of the surface of materials at the atomic
and molecular level, have provided a wealth of information about a host of materials,
from integrated circuit chips to biological molecules. Indeed, the advent of the SPMs has
helped to usher in the era of nanomaterials—materials whose properties are designed by
engineering atomic and molecular structures.

Figure 4.16a is a bar chart showing dimensional size ranges for several types of struc-
tures found in materials (note that the axes are scaled logarithmically). The useful dimen-
sional resolution ranges for the several microscopic techniques discussed in this chapter