Neutron diffraction has been used to study the structure in two series of xCaO center dot(2 - x)MgO center dot 2SiO(2) and xK(2)O center dot(2 - x) MgO center dot 4SiO(2) glasses and the effect of Ca-Mg and K-Mg mixing, showing a different chemical dependence of the structure of these mixed glasses. The data are consistent with a random mixing of CaSiO3 and MgSiO3 structures for the Ca/Mg substitution. The coordination of Ca and Mg remains constant in Ca-Mg silicate glasses but a decrease of Mg coordination is observed in the K-Mg silicate glasses with the addition of K2O. In these latter glasses, the medium range order is also significantly affected by the K/Mg substitution, due to the distinct structural role played by K and Mg in these glasses. (C) 2010 Elsevier B.V. All rights reserved.
Cormier, L. Calas, G. Cuello, G. J. 12th International Conference on the Physics of Non-Crystalline Solids (PNCS12) SEP 06-09, 2009 Foz do Iguacu, BRAZIL Sp. Iss. SI