Mechanical properties rare earth elements

The periodicity of chemical properties arises from filling of successive quantum mechanical shells of electrons. For example, filling of the s,p shells, with capacities of 8 electrons each, and the d shells, which can hold up to 10 electrons, is associated with the main group and transition elements, respectively (Fig. 1.1). Before the advent of quantum theory, two classes of elements were known that seemed not to fit the Mendeleyevian scheme an uncertain number of rare earth elements or lanthanides— metallic elements, discovered throughout the 1800s, that form oxides of... 

TABLE 2. MECHANICAL, ELECTRICAL, AND OXIDE PROPERTIES OF RARE-EARTH ELEMENTS... 

On the other hand, the rare earth elements constitute about one fourth of all existing metals. They form a group of elements closely related in their chemical, physical and metallurgical properties. In particular, most rare earth metals possess a similar electronic structure while other relevant properties often vary in a gradual, systematic manner. Thus, it appears that the rare earth metals constitute, potentially at least, favorable systems for the study of some of the basic factors which determine diffusion mechanisms in metallic systems. 

Sno84] Snow, D.B., Structure and Mechanical Properties of Laser-Consolidated Ti-6A1-4V and Ti-6Al-2Sn-4Zr-6Mo with Rare Earth Element Additions, in Laser Processing of Materials, K Mukheijee and J. Mazumder, Ed., The MetaUurgical Society, 1984, p. 83-89... 

Lanthanum is the first element of the sixth-period transition metals. Its properties are close to those of the other rare earth elements and, as a consequence, the catalytic behavior of the lanthanum triflate is also very close to that of the entire series. An important example concerning the stability of these compounds in water is that indicating the capability of metal triflates, such as Yb(OTf)3, Eu(OTf)3, Sc(OTf)3 or La(OTf)3, to catalyze the hydration of alkynes to the corresponding ketones [56]. However, the interest in water-compatible lanthanide triflate-based catalysts is much larger and mainly includes the carbon-carbon bond-forming reactions. To increase the utility of these catalysts understanding of their aqueous mechanism is very important. For such a purpose, dynamic measurements of the water... 

In recent years, a number of Mg alloys have been tested under in vitro and in vivo conditions to understand their corrosion behaviour and mechanisms (Witte et al. 2006 Kannan and Raman, 2008, 2010 Kannan, 2010 Walter and Kannan, 2011). AZ series alloys show a lower corrosion current than that of pure Mg. However, aluminium-containing Mg alloys may not be the ultimate choice, simply because of the potentially toxic effects of high aluminium levels in body fluid. The influence on corrosion properties of calcium and rare-earth elements added to Mg and its alloys has been investigated, but the improvement was not significant. 

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