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Mössbauer spectroscopy, XRPD, and SEM study of iron‐containing Na 2 O‐B 2 O 3 ‐SiO 2 glasses
Author(s) -
Ko Marina,
Polyakova Irina,
Stolyar Sergey,
Simonenko Nikolay,
Simonenko Tatiana,
Zolotov Nikita,
Semenova Ekaterina,
Antropova Tatiana
Publication year - 2021
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17744
Subject(s) - alkali metal , crystallization , mössbauer spectroscopy , amorphous solid , magnetite , materials science , powder diffraction , analytical chemistry (journal) , spectroscopy , annealing (glass) , crystallography , valence (chemistry) , mineralogy , chemistry , metallurgy , physics , organic chemistry , chromatography , quantum mechanics
Glasses in the Na 2 O‐B 2 O 3 ‐SiO 2 ‐Fe 2 O 3 system are suitable for producing magnetic porous glasses—host matrices for multiferroic composite materials for spintronics applications. Successful synthesis of such materials is dependent on the knowledge of crystallization and immiscibility areas in this system. Here, we report new findings for such glasses with a constant SiO 2 concentration of 70 mol %, containing 7‐12 mol % Fe 2 O 3 , whose compositions lie in the low (2 mol % Na 2 O) and higher (8‐12 mol % Na 2 O) alkali regions, heat‐treated at 550°C. Glasses were studied using analytical chemistry methods and investigated by means of Mössbauer spectroscopy, XRPD and SEM. We outlined the immiscibility area boundary in the chosen silica cross‐section for 550°C, indicating the region of interconnected morphology and the crystallization fields of magnetite and FeSiO 3 , and correlated them with data on the valence and coordination state of iron in glasses. We find that both Fe 3+ and Fe 2+ ions in the low‐alkali region are octahedrally coordinated, in higher alkali area Fe 3+ and Fe 2+ are tetrahedrally and octahedrally coordinated, respectively. A significant amount of Fe 2+ in the low‐alkali region can be the cause of the FeSiO 3 formation. The usual crystalline phase in non‐X‐Ray amorphous glasses is magnetite, precipitating at the annealing stage.