No abstract

No 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 Various compositions are studied where SiO2 have been replaced by TiO2.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.

Brillouin light scattering (BLS) spectroscopy and molecular dynamic (MD) simulations allowed the identification of a relationship between the elastic properties and the structure of K-containing glasses of formula (K2O) x -(SiO2)1–x , having different K2O concentrations. Excellent agreement was observed between experimental data and simulations. The peculiar elastic properties observed for these potassium silicate glasses have been extensively discussed in terms of structural and energetic features of the materials. Elastic properties were shown to be strongly dependent on the asymmetry of potential energy in the K–BO interactions and the K–NBO interactions. A low K2O content (below 10–15% K2O) appeared to be in favor of K+–BO interactions and high asymmetry of potential energy, whereas a high K2O content (from 10 to 15% K2O) was in favor of K+–NBO interactions with lower asymmetry. Our results suggest a possible explanation to the observed anomalous dependence of elastic properties of potassium silicate glasses with K2O amount.

No abstract