Phase and Morphology Control of Magnesium Nanoparticles via Lithium Doping

Abstract

We present experimental phase stability and particle morphology changes of metallic magnesium powders with the incorporation of lithium and gold as dopant and oxidation barrier coating, respectively. The crystal structure of the magnesium powders changes from hexagonal close-packed to body-centered cubic as the concentration of lithium dopant is increased. The phase change influences powder morphology and results in a modification of the powder shape from spherical to elongated rods, as confirmed by transmission electron microscopy. The crystallite size also decreases from around 100 to 30 nm. Differential scanning calorimetry analyses show that the powders with lithium transform from amorphous to crystalline at a lower temperature in comparison to powders without lithium. The results provide important insights into the formation of body-centered cubic magnesium alloys.

Phase and Morphology Control of Hexagonal MoO3 Crystals via Na+ Interactions: A Raman Spectroscopy Study

“…The presence of needle-like structures and incomplete elongated crystals shows the presence of α-MoO 3 , which agrees with the XRD and Raman results. Thus, from SEM, it is seen that powder morphologies − can be controlled by varying the phases in this material. The darker rectangular structures from samples AP10 and AP15 were analyzed by EDS and are depicted in Figure .…”

Predicting the Geometry of Core–Shell Structures: How a Shape Changes with Constant Added Thickness

“…Solid nanoparticles can be observed using techniques such as electron microscopy. 1,16,[20][21][22][23][24][25]28 Similarly, protein structures, and thus their shapes, may be experimentally determined using, for example, X-ray diffraction, NMR, and cryo-electron microscopy. 29−31 However, for both nanoparticles and proteins, we are limited to measurements of shape only after fully determining their structure with very little a priori understanding of the shape.…”

“…In all of these cases, little is known about how the interior and exterior shapes of core/shell-type objects are related. Solid nanoparticles can be observed using techniques such as electron microscopy. ,,− , Similarly, protein structures, and thus their shapes, may be experimentally determined using, for example, X-ray diffraction, NMR, and cryo-electron microscopy. − However, for both nanoparticles and proteins, we are limited to measurements of shape only after fully determining their structure with very little a priori understanding of the shape. This strictly post hoc view precludes a broader understanding of the shape and the impact of a shell.…”

Morphology Control of Tantalum Carbide Nanoparticles through Dopant Additions

“…Studies have explored the shape control of transition metal carbide nanoparticles to exploit the high surface area-to-volume ratio in applications such as gas adsorption and chemical sensing whereby specific facets, such as those with steps and kinks, will better facilitate chemical reactions. , Modeling studies have looked at the molecular adsorption of H 2 O on ZrC, to obtain cubes and octahedrons, and carbon adsorption on Ru to produce nanorods . Strain effects have also been explored as parameters for morphological modification of copper and nickel particles, and doping has been applied for obtaining nanorods of magnesium . In addition, modeling − and experimental techniques − have been applied for exploring the behavior of borides of cubic and other morphologies.…”

“…9 Strain effects have also been explored as parameters for morphological modification of copper and nickel particles, 10 and doping has been applied for obtaining nanorods of magnesium. 11 In addition, modeling 12−17 and experimental techniques 18−23 have been applied for exploring the behavior of borides of cubic and other morphologies. Moreover, experimental efforts have investigated shape change in cubic carbides as a function of carbon stoichiometry, which influences the relative growth rate of the dominant {111} and {100} facets.…”