Vanadium in Borosilicate Glass

• Published in: Journal of the American Ceramic Society Vol. 98; no. 1; pp. 88 - 96
• Main Authors: Sengupta, Pranesh, Dey, Krishna K., Halder, Rumu, Ajithkumar, Thalasseril G., Abraham, Geogy, Mishra, Raman K., Kaushik, Chetan P., Dey, Goutam K.
• Format: Journal Article
• Language: English
• Published: Columbus Blackwell Publishing Ltd 01.01.2015; Wiley Subscription Services, Inc
• Subjects: Addition polymerization; Borates; Borosilicate glasses; Ceramics; Glass; Networks; NMR; Nuclear magnetic resonance; Polymers; Silica; Silicates; Vanadium; Vanadium pentoxide
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.13303

Understanding the role of V2O5 within borosilicate glass matrices is important for the development of novel matrices toward immobilization of sulfate containing high‐level nuclear wastes. Present investigation shows, within sodium barium borosilicate glass matrix V2O5 can be homogeneously added up to 5 mol% and beyond which it separates out into three phases, for example, (i) silica (ii) Barium (Ba) – Vanadium (V) oxide, and (iii) glass matrix. 29Si MAS NMR (Nuclear Magnetic Resonance) studies of the samples show that below 5 mol% V2O5 addition, silicate network is dominantly constituted of Q2 and Q3 structural units, whereas above this, the network gets more polymerized through formation of Q3 and Q4 units. In case of borate network, 11B MAS NMR investigations revealed that the concentration of BO4 [(0B, 4Si)] unit increases gradually up to 5 mol% and then it decreases at the cost of BO4 [(1B, 3Si)], BO3 (symmetric) and BO3 (asymmetric) units. Micro‐Raman analyses of the samples showed that with additions of V2O5 in diluted concentrations, amorphous silicate network remained unaltered, whereas some amplification in signals corresponding to ring‐type metaborate and VO5 units exists. It is therefore apparent from both MAS‐NMR and micro‐Raman studies that with V2O5 additions within the solubility limit (≤5 mol%), borate network gets depolymerized leading to decrease in hardness from an average value of 5.0–4.2 GPa.