Diffraction SADP

Fig.6 AJIoy AlZn78 quenched from 643K to room temperature water, (a) Transmission electron micrograph, (b) Corresponding Selected Area Diffraction Pattern (SADP).

Figure 13 SADP in [001] orientation for (a) the sample annealed in (a) N2 (b) in 02. The patterns are at the same magnification, (c) [001] convergent beam diffraction pattern of the sample annealed in oxygen. HOLZ is arrowed.

Figure 5. (a) TEM microstructure of Cr-35 at. % Re alloy deformed at 20 °C, e = 71% cell structure has formed, (b) Corresponding selected area diffraction pattern (SADP). 

EDX Energy dispersion X-ray (analysis) SADP Selected-area diffraction pattern... 

Convergent beam electron diffraction (CBED) strictly refers to diffraction using an electron probe in a TEM with very large convergence angle. When this convergence angle becomes small the conditions are similar to the spot pattern obtained with parallel illumination in the conventional Selected Area Diffraction Patterns (SADP) as is shown in Fig. 1. 

This type of small angle patterns are termed as microdiffraction patterns (MDP). In practice, the convergence of the probe usually is controlled by the second condenser aperture [1, 2]. Table 1 gives the comparison between both diffraction procedures, SADP and CBED. 

Insert the selected area diffraction aperture, focus the image and switch the diffraction mode. Thus, a conventional SADP is obtained as starting point for the next operations. 

In the case of advanced ceramics and powders of nanometric size, the use of the classical selected area diffraction Patterns (SADP) by using different apertures in the electron path in the TEM is very short. In these cases and similarly for Zr02/mullite materials, the very small size of intragranular zirconia formed in the reaction sintered process inside the matrix, reaching 50-300 nm sizes, makes it fully necessary to use higher resolution in the electron diffraction analysis. 

The closest packed (110) planes of vanadium antimonate lattice form the best developed faces of vanadium antimonate crystals. The selected area diffraction pattern (SADP) with [110] zone axis taken from vanadium antimonate crystal is presented in Fig. 6. The high catalyst selectivity of the oxidized catalyst should be mainly connected with evolution of (110) surface of the vanadium antimonate crystals occurring in oxidizing atmosphere. 

Figure 7. TEM photomicrographs showing BaTiOg formation from the anatase precursor as a function of reaction time (a) 5 min (b) 25 min (c) 60 min and (d) SADP from 60 minutes. The AN and BT represent diffraction spots for ihc anatase and BaTiO, respectively.

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