Computational insights into the structure of barium titanosilicate glasses

Abstract

Understanding the role of TiO2 in BaO‐TiO2‐SiO2 (BTS) glasses is one of the keys to develop new glasses and glass‐ceramics for different technological applications. For the first time, molecular dynamics simulations were conducted to get new insights into the atomic structure of the BTS glasses and their elastic moduli. Various compositions are studied where SiO2 have been replaced by TiO2. The calculated mechanical properties of our models are observed to depend linearly on TiO2 content. However, the structure‐induced changes are far from such dependence. The structural results indicate that BTS glasses are mainly built on four types of basic units: SiO4, TiO4, TiO5 and TiO6. This high structural heterogeneity induced by the three coordination states of Ti is found to have an impact on the medium range order by increasing the rings number, the polymerized regions, and by transforming Q3‐Q4 and Q2 without neglecting the increase in Q5 and Q6 species. Those structural modifications of the BTS glass network features have been found to be consistent with available experimental data.

Atomic Structure and Modifiers Clustering in Silicate glasses: Effect of Modifier Cations

“…As illustrated in Fig. 6(b) the bridging oxygen have the highest population in the present silicate glasses; this is in agreement with previous experiments and molecular dynamics [6,7,13,47,48]. Moreover, the existence of NBO in all glasses indicates that the network is depolymerized to some extent.…”

“…The addition of network modifiers results in depolymerization of the glass network, by breaking the Si-O-Si bonds and transforming the BO to nonbridging oxygen (NBO) linked to only one silicon and free oxygen (FO) and sometimes to oxygen triclusters (TBO), as in the case of alkaline and alkaline-earth aluminosilicates. This depolymerization affects remarkably the properties of the glass [6][7][8][9][10][11][12].…”

“…In order get some insights into the atomic structure of the glass, we use molecular dynamics (MD) simulations, which is an effective method to help to investigate and understand the atomic-scale behavior of materials and have been applied in studying and oxide glasses [6,7,[34][35][36]. We study the effect of the modifier type on the structural properties of a series of modified silicate glasses were the concentration of the modifiers was fixed to 25 mol%.…”

“…We used on the well-established potential developed by Pedone et al [37]. This potential gives a realistic agreement with available experimental data, as mentioned in the literature [3,7,13,34,[37][38][39][40]. Potential parameters and partial charges are given in the reference ( [37]).…”

Atomistic insights into the mixed-alkali effect in phosphosilicate glasses

“…In this potential, the particles are treated as charge points interacting via Coulomb forces, a Morse function to describe the short-range interactions between pairs of atoms, and an additional r −12 repulsive contribution necessary to model the interactions at high pressure and temperature. This potential gives a realistic agreement with available experimental data as mentioned in the literature [6,17,[22][23][24][25][26] as it was designed to reproduce structural and mechanical properties of a wide range of oxide glasses. Potential parameters and partial charges are given in the Ref.…”