Magnesium thermodynamic parameters

The surface-phase layers will difier in character depending on the stractures of metal and oxide. On certain metals (zinc, cadmium, magnesium, etc.), loose, highly porous layers are formed which can attain appreciable thicknesses. On other metals (aluminum, bismuth, titanium, etc.), compact layers with low or zero porosity are formed which are no thicker than 1 pm. In a number of cases (e.g., on iron), compact films are formed wfiicfi fiave a distorted lattice, owing to the influence of substrate metal stracture and of the effect of chemical surface forces. The physicochemical and thermodynamic parameters of such films differ from tfiose of ordinary bulk oxides. Because of the internal stresses in the distorted lattice, such films are stable only when their thickness is insignificant (e.g., up to 3 to 5 nm). 

Application of SPD techniques to metal hydrides is a new field of research. Skripnyuk and Rabin were the first to use ECAP to improve the hydrogen storage properties of Mg-based alloys [254, 255]. The first study on ECAP-processed magnesium alloy ZK90 showed an improvement in sorption kinetics without loss of hydrogen capacity or change in thermodynamic parameters [254]. figure 4.12 shows comparable results for the Mg-Ni eutectic alloy [255]. 

Both the chemical shift and the relaxation rate may serve as an experimental observable in studies directed towards obtaining structural and thermodynamic information on cation binding. There are very few such studies in the literature making use of direct observation of alkaline earth resonances. The choice of the two possible experimental parameters depends on the sensitivity of either quantity to environmental changes. From early studies of the concentration dependence of shieldings in aqueous magnesium salts (104)... 

A thermodynamic model developed by Barba, Brandani and di Giacomo (1982) described the solubility of calcium sulphate in saline water. A system of equations based on Debye Hiickel and other models was used to describe isothermal activity coefficients of partially or completely dissociated electrolytes. Using binary parameters, good agreement was claimed between experimental and predicted values of calcium sulphate solubility in sea water and brackish brines including those with a magnesium content. 

Table 9.5. Thermodynamic and Kinetic Parameters for Magnesium Binding to Phosphate Containing Ligands by Mg NMR Spectroscopy ...

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