Artifacts in Transmission Electron Microscopy - Sample Preparation Topic for Transmission Electron Microscopy - page 128

Glide planes : Plane defect (2D) corresponding to the dense atomic plane of a
crystal where dislocations propagate under the effect of a stress. This strong
pressure on the crystal causes movements of whole atomic planes.
Techniques involved: sawing, ultrasonic cutting, mechanical polishing, dim-
pling, tripod polishing, and ultramicrotomy.
Particle aggragation : Agglomerate of particles formed by poor dispersion
of isolated particles, or by migration of particles in solution during the
dessication process. This is due to attractive forces between particles.
Techniques involved: fine particles dispersion technique.
Twinning : Plane defect (2D) corresponding to a joint or perfect mirror interface
at the atomic scale. The atomic plane of the twin is common to the crystal
networks of two grains. Their formation can be caused by a thermal phase
transformation or mechanical stresses, a violent impact can cause twinning
in brittle materials.
Techniques involved: sawing, ultrasonic cutting, mechanical polishing, dim-
pling, tripod polishing, and ultramicrotomy.
Strain hardening : Change in microstructure due to mechanical stresses, which
induces a set of disturbances in the material involving dislocations and glide
planes.
Techniques involved: sawing, ultrasonic cutting, mechanical polishing, dim-
pling, tripod polishing, and ultramicrotomy.
Selective abrasion : Thinning of matter at different rates by mechanical pol-
ishing. It can reveal a phase or lead to its disappearance through the faster
abrasion of one phase over another. It can create surface roughness.
Techniques involved: mechanical polishing, dimpling, and tripod polishing.
Roughness : State of the non-plane surface revealing either scratches caused
by material tearing or variations in thin slice thickness caused by selective
abrasion or the tearing of matter.
Techniques involved: sawing, ultrasonic cutting, mechanical polishing, dim-
pling, tripod polishing, ultramicrotomy and cryo-ultramicrotomy.
Structural change : Partial or total change of the crystallographic organization
caused by mechanical stresses. It can lead to a change in form, amor-
phization of the crystal network, a change in network, crystallization, or
re-crystallization.
Techniques involved: mechanical polishing, dimpling, and tripod polishing.
Microstructural change : Partial or total change in the structural organization of
microstructural components that can be caused by mechanical effects. It can
result in changes in morphology, redistributions of phases, changes in crystal
structure, precipitation, chemical gradients, formation of new phases, etc.