Comparisons of Techniques - Sample Preparation Topic for Transmission Electron Microscopy - page 218

Fig. 8.32 TEM image of the
same sample as shown in
Fig. 8.31. This image shows
thick interfaces over the
entire surface as well as the
porosities maintained in the
PZT film observed in SEM.
( V. Radmilovic, J. Ayache
NCEM, Berkeley )
3.2.5 Comparison of “Tripod Polishing” and “Tripod Polishing + Ion Milling”
Techniques
Tripod Polishing Technique (“Techniques” Chapter 4, Section 3) - Tripod
Polishing + Ion Milling (“Techniques” Chapter 3, Section 5)
Bulk composite ceramic material: YBa 2 Cu 3 O 7 /Y 2 BaCuO 5
Comparison discussion : In both of these examples, the tripod polishing technique
produces the best results for studying the microstructure of the interfaces.
In fact, the tripod polishing technique can be used to analyze all interfacial
defects (dislocations, stacking faults, etc.) without irradiation damage and over a
large area.
The ion bombardment technique never results in completely observable inter-
faces around a precipitate because of preferential etching and because of the
material's sensitivity to irradiation under the ion beam, which promotes diffusion
and selective loss of atoms. On this type of preparation, the electron beam provides
annealing following diffusion and stabilizes the defects formed that are extrinsic to
the starting microstructure.
In the case of tripod polishing technique, there is no annealing phenomenon
under the electron beam, and the structure remains stable during observation
(Figs. 8.33 and 8.34) .