Influence of Fe3+ ions on optical, structural, thermal and mechanical properties of Li2O–Na2O–K2O–ZnO–B2O3 based glass system

• Published in: Ceramics international 2020-03, Vol.46 (4), p.5213-5222
• Main Authors: Subhashini, Shashikala, H.D., Udayashankar, N.K.
• Format: Article
• Language: English
• Subjects: Alkali borate glasses; Fracture toughness; FTIR and Raman spectroscopy; Thermal stability; Vickers microhardness
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2019.10.269

The effect of addition of Fe3+ ions in Li2O–Na2O–K2O–ZnO–B2O3 based glass system have been studied. The melt quenching technique is used to prepare the glass samples. The X-ray diffraction studies confirmed the amorphous nature of the samples. DSC thermographs indicate that the Tg is decreasing as the addition of Fe2O3 content. Increase in thermal stability is observed upon adding K2O to the F0 sample and increase in the Fe2O3 content further enhanced the thermal stability up to 187 °C. Optical band gap energy (Eg) of the studied glass system is found to reduce with increasing Fe2O3 content. A band observed around 450 nm in UV absorption spectra is due to the d-d transition of 6A1g(S) → 4T2g(G) which indicates the presence of iron ion in trivalent state (Fe3+) with distorted octahedral symmetry. The oxide ion polarizability values determined using the refractive index and optical band gap energy are found to be increasing monotonically with partial incorporation of K2O content and with increasing Fe2O3 content. The FTIR and Raman spectroscopy studies confirmed the network modifier role of Fe2O3. The radial-median cracks produced due to Vickers indentation were studied and it confirmed the enhancement in brittleness of the samples as Fe2O3 content increased. Further efforts have been made to analyse and establish correlation between the physical and mechanical properties with the structural modification of the studied glass system.