PhD Thesis_RuiMSMartins.pdf - RUN UNL

In-situ XRD studies during growth of Ni-Ti SMA films and their complementary ex-situ characterization
Characteristics of the equipment:
• TEM CM300 (300 kV) with LaB 6 - cathode and SuperTWIN-α lens (line resolution
0.14 nm);
• CCD Multi Scan Camera (GATAN) for digital imaging (including image processing);
• EDX unit (EDAX), S-UTW-window and Si-detector suitable down to Z = 5.
The TEM equipment is appropriate for high-resolution (HR) thus offering the
possibility for lattice-fringe imaging of single-crystalline regions. For phase identification,
electron diffraction, lattice imaging and imaging processing by FFT are used. The
identification of elements in selected small regions as well as the element mapping of
extended regions can be done using the supplementary analytical EDX-device. In this work,
TEM observations were especially relevant for the study of the interface morphology,
allowing the identification of the phases present resultant of interfacial reactions.
2.6. SCANNING ELECTRON MICROSCOPY (SEM)
Scanning Electron Microscopy (SEM) has been used in some cases to characterize the
surface morphology of the films. It is known that when a Ni-Ti film undergoes a phase
transformation, both its surface roughness and its refractive index change. A different surface
morphology is thus expected for the B2, R and B19’ phases. Energy dispersive X-ray
spectroscopy (EDX) was also useful in some cases for a fast rough control of the film
composition as well as to analyse the target’s material composition and to detect possible
impurities.
Fig. 2.16: Scanning electron microscope Hitachi S-4800 II.
Chapter 2 – Experimental Details 96