Introduction to Materials - Sample Preparation Topic for Transmission Electron Microscopy - page 15

Amorphous Materials

Amorphous

Local order
Few 0.1nm
Chemical and structural homogeneity

Poorly Organized

Poorly-Organized Materials

Start of crystal growth
Ranging from 1 nm to 100 nm
Distribution in organized domains Multilayer

Poorly Organized

Nano - Micro Crystallized Material s

Nano-Micro
Crystallized

100nm < crystallites <1µm
Distribution and crystal/matrix relations
Amorphous-crystal structural transition

Classic
Polycrystalline

Polycrystalline Materials

Crystal size > 1µm
Relation of orientation, texturation
Ordinary, special interfaces
Extended defects (dislocations,
twins, second phases, precipitates,
cracks, etc.)
Point defects

Textured
Polycrystalline

Monocrys t alline Materials

Size: few µm few mm
Defects tied to crystal growth:
dislocations, twins, point defects, etc.
Structural homogeneity
Chemical homogeneity
Boundary and boundary plane orientation

Monocrystalline

Bulk Bi c rystal

Size: few µm few mm

Detects tied to crystal growth:
Structural homogeneity
Chemical homogeneity
Orientation of the boundary and
boundary plane

Bicrystalline

Fig. 2.2 Different types of organization of bulk 3D materials at the microscopic scale

Amorphous materials have a short-range order, which is the interatomic distance.
The result is that there is no crystalline order. The analysis of these materials will
focus mainly on chemical composition and chemical and structural homogeneity.
Crystal growth will be limited to the growth caused by the local crystallization of
the nanoparticles present, as can be observed in fluoride glasses, which are used
for their optical properties. These are bulk materials and may be either compact or
porous.
Poorly organized materials are materials whose crystal growth extends over dis-
tances of up to 100 nm. Examples of poorly organized materials often include
natural organic materials derived from the alteration of trees, forests, algae, etc.,