Artifacts in Transmission Electron Microscopy - Sample Preparation Topic for Transmission Electron Microscopy - page 134

Techniques involved: electropolishing, chemical polishing, twin-jet electrolytic
thinning, full-bath electrolytic thinning, twin-jet chemical thinning, and full-
bath chemical thinning.
Changes in phase distribution : Aggregation of chemical elements caused by
thermal diffusion or aggregation of several elements of a microstructure that
might lead to the disappearance of the initial phases.
Techniques involved: electropolishing, chemical polishing, twin-jet electrolytic
thinning, full-bath electrolytic thinning, twin-jet chemical thinning, and full-
bath chemical thinning.
2.4 Physical Preparation-Induced Artifacts
Deformation : Change in shape caused by the formation of ice crystals in a
sample that should contain only vitreous ice.
This artifact can generate a change in the conformation and distribution of the
matter.
Techniques involved: cryo-fixation and frozen hydrated film
Microstructural changes : Partial or total change in the structural organiza-
tion of the components of a microstructure, caused by thermal effects (low
temperatures). It can result in changes in morphology, phase redistribution,
changes in crystal structure, precipitation, chemical gradients, formation of
new phases, etc.
Techniques involved: cryo-fixation, substitution-infiltration-embedding in cry-
ogenic mode, cryo-ultramicrotomy, and frozen hydrated film.
Segregation of liquid phases : Migration of a solution in a solvent during a
change of physical state that occurs too slow.
Techniques involved: fine particle dispersion Technique, cryo-fixation.
2.4.1 Secondary Thermal Damage Induced During Physical Preparation
Deformation : Change in shape due to heating during physical preparation, lead-
ing to the re-crystallization of vitreous ice. This artifact can generate a change
in matter conformation and distribution.
Techniques involved: cryo-fixation, substitution-infiltration-embedding in cry-
ogenic mode, cryo-ultramicrotomy, frozen suspension film.
Particle aggregation : Agglomeration of particles caused by the mobility of
metallic particles deposited on the sample surface, which is created by a ther-
mal effect or charge effect between ionic particle interaction. This leads to
the creation of larger particles through coalescence.