Raman and X-ray photoelectron spectroscopy study on the influence of La2O3 on the melt structure of SiO2–CaO–Al2O3–MgO

• Published in: Ceramics international 2022-09, Vol.48 (18), p.25933-25939
• Main Authors: Guo, Wentao, Wu, Jun, Liu, Xinkun, Wang, Jingming
• Format: Article
• Language: English
• Subjects: La2O3; Raman spectroscopy; Si–O/Al–O tetrahedron; X-ray photoelectron spectroscopy
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2022.05.270

In order to gain more insights into the influence of rare earth elements on the melt structure of SiO2–CaO–Al2O3–MgO glass ceramics, Raman and X-ray photoelectron spectroscopy techniques were used to study the influence of La2O3 on the Si–O/Al–O tetrahedron structure within SiO2–CaO–Al2O3–MgO–quenched glass samples in this study. Results showed that some Raman peak shapes at low frequencies (200–840 cm−1) changed significantly after the addition of La2O3, compared to the high frequency (840–1200 cm−1) region that corresponds to the [SiO4] structure, suggesting that the depolymerization of the low-frequency T–O–T (T=Si or Al) structure was more prevalent with La3+ addition. Besides, the depolymerization extent of the Si–O/Al–O tetrahedral network varied when the melt composition altered. Most notably, depolymerization is the most significant at a low CaO/SiO2 ratio (0.25) and a high Al2O3 content (8%). Meanwhile, La3+ can promote the transformation of Si–O–Si and Al–O–Al bonds to the Si–O–Al ones, thereby forming a complex ionic cluster network interwoven with Si–O and Al–O tetrahedrons.