Introduction to Materials - Sample Preparation Topic for Transmission Electron Microscopy - page 4

Regardless of the material's complexity, properties, or functions, it is necessary
to master all steps of the preparation techniques for the TEM. It is equally important
to know the limits of each technique, its drawbacks, and especially the artifacts that
it may induce in order to be sure that the analysis reveals the true nature of the
material.

1.3 General Problems Presented by Microstructure Investigations

When studying a material, the microscopist is confronted by the relationships
between its physical, chemical, thermal, and dynamic histories. The conditions
the material was subjected to will dictate its particular microstructure formation
at different scales, and thus its physical, chemical, and/or biological properties.
Regardless of the material type, three main parameters can be presented in the
form of a triangular diagram. Figure 2.1 shows these parameters: (i) microstructure,
(ii) growth related to its surroundings, and (iii) properties, which are interdependent.
If just one of these parameters changes, then the other two are disrupted, sometimes

Physical, chemical, thermal
and dynamic history
of the material (ii)
Natural evolution, type of synthesis, growth mechanisms,
behavior at variable temperature, dynamic behavior,
atomic, ionic, and molecular diffusion

- Physical State of the Material
Compact, porous, with liquid solution
- Hardness-Brittleness of the
Material
Soft, hard, brittle, resistant

Organization of the Material
Bulk, Single-Layer
Multilayer, Single Particles
Single-phase, Multiphase
Cristallinity of the Material
Amorphous, Poorly-Organized
Microcrystalline, Polycrystalline
or Monocrystalline

Metal
Semiconductor
Ceramic
Mineral
Polymer
Biological Material
Mixed-Composite Material

Metal
Semiconductor
Ceramic
Mineral
Polymer
Biological Material
Mixed-Composite Material

Physical Properties (iii)
Mechanical, magnetic, electrical,
electronic, optical
Chemical Properties
Oxidoreduction, ionic transport
synthesis, degradation, polymerization
Biological Properties
Organic chemistry of carbonaceous
compounds, Biosynthesis, catabolism,
enzymatic activities, self-replication

(iii)

Microstructure (i)
- Organization of the structure
at different scales
Chemical and Structural Distribution
- Nature and distribution of defects
- Type of chemical bonds
- Functional Sites

Fig. 2.1 Schematic representation of the problems to be resolved in materials science and biology
when studying the microstructure of a material and the relationship between (i) its microstructure,
(ii) the history of the material, and (iii) its properties