Structural and thermal influence of niobia in aluminoborosilicate glasses

Costa-silva, D.L.; Bartolomé, José F.; Silva, A.C.; Mello-Castanho, Sonia Regina Homem de

doi:10.1016/j.ceramint.2022.03.112

Cited by 6 publications

(3 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…showed the presence of NbO 4 in a glass when Nb 2 O 5 < 15 mol%, due to the size of Nb 5+ ions, tetrahedral coordination is extremely rare and Nb 5+ usually forms highly distorted octahedral units in a glass 28,29 . The integration of NbO 6 in a SiO 4 network is further substantiated by Costa‐silva et al 26 . who showed that the addition of Nb 2 O 5 to borosilicate glasses ruptures the SiO 4 tetrahedral network while also increasing the amount of corner‐sharing NbO 6 octahedra.…”

Section: Resultsmentioning

confidence: 75%

See 1 more Smart Citation

Dielectric polarizability of SiO₂ in niobiosilicate glasses

2023

View full text Add to dashboard Cite

Understanding the mechanisms contributing to dielectric properties of glasses is critical for designing new compositions for microwave frequency applications.In this work, dielectric permittivity was measured using a cavity perturbation technique at 10 GHz for a series of niobiosilicate glasses with the compositions (100-2x)SiO 2 -xNb 2 O 5 -xLi 2 O where x = 32.5, 30, 25, and 15 mol%. Permittivity measurements and glass compositions were used to calculate the polarizability of each cation-anion unit in the glass network using the Clausius-Mossotti equation. The SiO 2 polarizability in niobiosilicates was calculated to be 6.16 Å 3 , which is much higher than the SiO 2 polarizability in fused silica glass (5.25 Å 3 ), alkali modified silicates (5.37 Å 3 ), and aluminosilicates (5.89 Å 3 ). The increasing trend in SiO 2 polarizability is attributed to the disruption in the connectivity of the SiO 4 tetrahedral network as it accommodates different network formers. The high SiO 2 polarizability of 6.16 Å 3 accurately predicts measured dielectric permittivity when Nb 2 O 5 = 25, 30, and 32.5 mol%, but overpredicts measured permittivity when Nb 2 O 5 ≤ 15 mol%, which is attributed to a decrease in SiO 2 polarizability as the percentage of corner sharing SiO 4 tetrahedra with NbO 6 octahedra goes down. This work demonstrates that SiO 2 polarizability depends on chemistry and connectivity of the glass, which has important implications in designing glass compositions for microwave frequency applications.

show abstract

Section: Resultsmentioning

confidence: 75%

“…This is due to the high polarizability of Nb 5+ ions and the role Nb 2 O 5 plays in a glass network. It is known that Nb 2 O 5 can be both a network modifier 5,25 and network former 26 . While work by Gao et al 27 .…”

Section: Resultsmentioning

confidence: 99%

Dielectric polarizability of SiO₂ in niobiosilicate glasses

2023

View full text Add to dashboard Cite

show abstract

“…In contrast, the formation of neutral BO 3 units at a higher GeO 2 concentration could break the conduction pathways and reduce the mobility of the ions. According to the literature [ 69 , 70 , 71 ], the competition for charge compensation between highly charged cations is the fundamental reason for boron coordination. The field strength of different modifier cations such as Na + , Ba 2+ , and Ca 2+ [ 72 ] affects the enhanced stabilization of tetraborate groups by involving higher field strength cations in NBO-rich glasses.…”

Section: Resultsmentioning

confidence: 99%

Raman and Infrared Spectroscopy of Barium-Gallo Germanate Glasses Containing B2O3/TiO2

et al. 2023

View full text Add to dashboard Cite

Modified barium gallo-germanate glass hosts are still worthy of attention in studying structure–property relationships. In this work, two different series of glass systems based on (60-x)GeO2-xTiO2-30BaO-10Ga2O3 and (60-x)GeO2-xB2O3-30BaO-10Ga2O3 (x = 10, 30, 50 mol%) were synthesized, and their properties were studied using spectroscopic techniques. X-ray diffraction (XRD) patterns revealed that all fabricated glasses were fully amorphous material. The absorption edge shifted toward the longer wavelengths with a gradual substitution of GeO2. The spectroscopic assignments of titanium ions were performed with excitation and emission spectra compared to the additional sample containing an extremely low content of TiO2 (0.005 mol%). On the basis of Raman and FT-IR investigations, it was found that increasing the TiO2 content caused a destructive effect on the GeO4 and GeO6 structural units. The Raman spectra of a sample containing a predominantly TiO2 (50 mol%) proved that the band was located near 650 cm−1, which corresponded to the stretching vibration of Ti-O in TiO6 unit. The deconvoluted IR results showed that the germanate glass network consisted of the coexistence of two BO3 and BO4 structural groups. Based on the experimental investigations, we concluded that the developed materials are a promising candidate for use as novel glass host matrices for doping rare-earth and/or transition metal ions.

show abstract

New approach to niobia-modified borosilicate glasses for Cs waste immobilization

Costa-Silva,

Araujo,

Fungaro

et al. 2024

Journal of Materials Research and Technology

View full text Add to dashboard Cite

Structural and thermal influence of niobia in aluminoborosilicate glasses

Cited by 6 publications

References 44 publications

Dielectric polarizability of SiO₂ in niobiosilicate glasses

Dielectric polarizability of SiO₂ in niobiosilicate glasses

Raman and Infrared Spectroscopy of Barium-Gallo Germanate Glasses Containing B2O3/TiO2

New approach to niobia-modified borosilicate glasses for Cs waste immobilization

Contact Info

Product

Resources

About

Structural and thermal influence of niobia in aluminoborosilicate glasses

Cited by 6 publications

References 44 publications

Dielectric polarizability of SiO2 in niobiosilicate glasses

Dielectric polarizability of SiO2 in niobiosilicate glasses

Raman and Infrared Spectroscopy of Barium-Gallo Germanate Glasses Containing B2O3/TiO2

New approach to niobia-modified borosilicate glasses for Cs waste immobilization

Contact Info

Product

Resources

About

Dielectric polarizability of SiO₂ in niobiosilicate glasses

Dielectric polarizability of SiO₂ in niobiosilicate glasses