Atomic resolution TEM images of an identical location showing Al-matrix, Mg2Si and the interface between them, (a) prior to immersion, and following immersion in 0.1 M NaCl for (b) 3 s, (c) 30 s and (d) 30 min. (b′) shows atomic resolution Mg2Si following immersion in 0.1 M NaCl for 3 s. (d′) shows higher magnification image of d. Double arrowed dotted lines in (a-d, d′) and solid lines in (b and b′) indicate interfaces between the phases. Whilst single arrowed solid line in (b) and (b′) indicate the direction of corrosion propagation.

Contexts in source publication

Context 1

... resolution TEM imaging was performed along the [001] Al // [011] Mg2Si direction to understand the onset of corrosion at atomic scale and any influence of the SiOrich remnant on the surrounding Al-matrix, and the results are provided in Fig. 3. Such a resolution is essential because the electron diffraction and chemical composition analysis will not be able to reveal significant details when the extent of corrosion is at the atomic scale. In the pristine condition, clear atomic columns or lattice fringes of the Mg 2 Si particle and the Al-matrix were observed (Fig. 3 (a)). ...

Context 2

... are provided in Fig. 3. Such a resolution is essential because the electron diffraction and chemical composition analysis will not be able to reveal significant details when the extent of corrosion is at the atomic scale. In the pristine condition, clear atomic columns or lattice fringes of the Mg 2 Si particle and the Al-matrix were observed (Fig. 3 (a)). Following immersion for 3 s (Fig. 3 (b)), the lattice structure within the Mg 2 Si particle transformed to amorphous, which was revealed to be of SiO-rich phase from the chemical composition analysis (Fig. 1 (a′-g′)), and the lattice structure of the Al-matrix did not ...

Context 3

... is essential because the electron diffraction and chemical composition analysis will not be able to reveal significant details when the extent of corrosion is at the atomic scale. In the pristine condition, clear atomic columns or lattice fringes of the Mg 2 Si particle and the Al-matrix were observed (Fig. 3 (a)). Following immersion for 3 s (Fig. 3 (b)), the lattice structure within the Mg 2 Si particle transformed to amorphous, which was revealed to be of SiO-rich phase from the chemical composition analysis (Fig. 1 (a′-g′)), and the lattice structure of the Al-matrix did not ...

Context 4

... the corrosion did not initiate uniformly upon the Mg 2 Si particle at its periphery ( Fig. 2 and 3 (b)). In fact, corrosion initiated randomly at few of the interfaces of the Mg 2 Si particle and the Al-matrix, and propagated to completely dealloy the Mg 2 Si particle. The direction of corrosion propagation was marked by a single arrowed line in Fig. 3 (b, b′). It is evident that with the propagation of corrosion, the crystalline Mg 2 Si structure transforms to amorphous SiOrich phase (Fig. 3 (b′)). Following complete dealloying of the Mg 2 Si particle, i.e., after 30 s and 30 min immersion, the lattice structure of the Al-matrix at the interface of the amorphous SiO-rich phase remained ...

Context 5

... at few of the interfaces of the Mg 2 Si particle and the Al-matrix, and propagated to completely dealloy the Mg 2 Si particle. The direction of corrosion propagation was marked by a single arrowed line in Fig. 3 (b, b′). It is evident that with the propagation of corrosion, the crystalline Mg 2 Si structure transforms to amorphous SiOrich phase (Fig. 3 (b′)). Following complete dealloying of the Mg 2 Si particle, i.e., after 30 s and 30 min immersion, the lattice structure of the Al-matrix at the interface of the amorphous SiO-rich phase remained unaffected (Fig. 3 (c, d and d′)), revealing that the SiO-rich remnant became electrochemically inert and did not initiate corrosion in the ...

Context 6

... b′). It is evident that with the propagation of corrosion, the crystalline Mg 2 Si structure transforms to amorphous SiOrich phase (Fig. 3 (b′)). Following complete dealloying of the Mg 2 Si particle, i.e., after 30 s and 30 min immersion, the lattice structure of the Al-matrix at the interface of the amorphous SiO-rich phase remained unaffected (Fig. 3 (c, d and d′)), revealing that the SiO-rich remnant became electrochemically inert and did not initiate corrosion in the Al-matrix even at the atomic scale. The electrochemical behaviour of Mg 2 Si in Al-alloys following extended period of exposure to 0.1 M NaCl at different pH was provided elsewhere [41]. In that study, it was revealed that the ...