Local Al site distribution in aluminosilicate glasses by 27Al MQMAS NMR

Environment of titanium and aluminum in a magnesium alumino-silicate glass

“…27 Al 1D NMR experimental spectra and the fitting models obtained with parameters given in table 2 (top) and contour plots of 27 Al MQ-MAS NMR spectra (bottom) for the (a) 2MgO-2Al 2 O 3 -5SiO 2 (COR) glass and for the (b) 2MgO-2Al 2 O 3 -5SiO 2 -TiO 2 (Ti-COR) glass. and [6] Al exist in this glass, as is observed in other Ca-aluminosilicate glasses [35] and Mg-alumino-silicate glasses [36,37]. When introducing titanium in the melts, we observe a slight increase of the chemical shift (δ iso ) and of the quadrupolar coupling constant (C Q ) of each site that can be correlated to an increased distortion of the Al environment.…”

“…Such an affinity for NBO to be linked with Si atoms has already been determined in calcium alumino-silicate glasses [44]. Recent studies have shown that the presence of NBO for such composition results from the presence of highly coordinated Al that are favored in the liquid state [35,42]. In the present case highly coordinated Ti species also promote the formation of NBO.…”

“…27 Al NMR results show a modification of the aluminosilicate network with the formation of highly coordinated aluminum atoms, mainly [5] Al, as TiO 2 is introduced. The presence of highly coordinated aluminum atoms is well established in alkaline-earth alumino-silicate glasses because alkaline-earth cations are less good charge compensators than alkalis [35][36][37]. However, quantitative evaluation of these species gives lower [5] Al and [6] Al content for the COR glass than for the Ti-COR glass.…”

Detailed Structure Elucidation of the Blast Furnace Slag by Molecular Dynamics Simulation

“…Several experimental techniques such as X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Raman and infrared (IR) spectroscopies, and nuclear magnetic resonance (NMR) spectroscopy have been applied for the purpose. [1][2][3][4][5][6][7] Also, viscosity and thermal expansivity of the molten slags have been measured by several researchers. 8,9) Molecular dynamics (MD) simulation can provide the unique information on the structural properties as well as dynamic properties such as diffusion, thermal expansion, etc., from an atomistic point of view.…”

Microstructural and Dynamical Heterogeneity Characteristics in Al2O3- 2SiO2 Liquid

“…At low pressure, Al atoms incorporate into Si-O network via non bridging oxygens. The Al-O bond is weaker in comparison to Si-O bond so that Al is more mobile than Si [18]. This leads to the bond easy to break into AlO 3 units and SiO 4 units.…”