Bi2O3 BaO Research Articles

Influence of TiO2 addition on the sealing performance of Bi2O3–BaO–SiO2–RxOy (R[dbnd]K, Ca, etc.) glass

A series of Bi2O3–BaO–SiO2–RxOy (designated BiBaSi glass) glass sealants doped with different contents of TiO2 were prepared by conventional melting and annealing technique. The onset of crystallization temperature was determined by differential thermal analysis. The CTEs along with transition temperature (Tg) and softening temperature (Tf) were determined from dilatometric measurement. X-ray diffraction was used to determine the crystal phases. Scanning electron microscopy was used to study the microstructure and an associated energy dispersive X-ray spectroscopy was used to study element distribution. The good matching of thermal properties and the strong adherence to the electrolyte and connector indicate that the composite glass with 7.3mol% TiO2 (BAS3) appeared to be a good candidate for SOFC sealing.

Influence of Al2O3 addition on the properties of Bi2O3–BaO–SiO2–RxOy (R = K, Zn, etc.) glass sealant

A series of Bi2O3–BaO–SiO2–RxOy (designated BiBaSi glass) glass sealants doped with different contents of α-Al2O3 have been investigated. Al2O3 was added as a modifier to affect the structure and the behavior of the glass. The thermal properties such as glass transition temperature (Tg), softening temperature (Tf) and coefficient of thermal expansion (CTE) were measured by a dilatometer. The sealing performance was investigated by sealing a SOFC single cell stack and measuring its open circuit voltage (OCV). Tg, Tf and suitable usage temperature of the sealants increased with increasing Al2O3 content in the glass, while CTE decreased. When the Al2O3 content was lower than 10wt.%, excellent sealing performance was observed.

Study of stoichiometrich glass ceramics formation in the BaO–Bi2O3–B2O3system

Study of stoichiometrich glass ceramics formation in the BaO–Bi₂O₃–B₂O₃system

Evolution of nanocrystalline BaBi2Nb2O9 in Li2B4O7–BaO–Bi2O3–Nb2O5 glass system

Transparent glasses and glass nano crystal composites (GNCs) of various compositions in the system (100−x)Li2B4O7–x(BaO–Bi2O3–Nb2O5) (where x=10, 20, and 30 in molar ratio) were fabricated via splat-quenching technique. The glassy nature of the as-quenched samples was established by differential thermal analyses. X-ray powder diffraction and transmission electron microscopic (TEM) studies confirmed the formation of layered perovskite BBN via a fluorite like phase. TEM studies revealed the presence of 10nm sized spherical crystallites of fluorite like BaBi2Nb2O9 phase in the glassy matrix of Li2B4O7 (LBO). The influence of composition on the dielectric and the optical properties (transmission, optical band gap) of these samples has been investigated.

Development of novel ternary tellurite glasses for high temperature fiber optic mid-IR chemical sensing

The properties of novel ternary tellurite glasses, based on the TeO2–BaO–Bi2O3 system, are reported for their applications in on-line chemical sensing and process control by characterizing the fundamental frequencies of molecular vibrations in the 2–5μm spectral region of mid-IR. The chemical sensing for process control also requires above room temperature operation (>100°C) for prolonged periods of time. Bulk samples of ternary tellurite glasses with a number of different compositions were prepared using heavy molecular weight oxides of TeO2, BaO, and Bi2O3. Infrared and Raman spectroscopic analysis was carried out together with differential thermal analysis to study the relationship between glass structure and thermal and viscosity properties. The temperature dependence of the viscosities of the glasses is also reported. The compositional dependence of Raman frequency shifts and the corresponding change in the coordination of Te–O structure is discussed. The results from the IR edge, reflection spectroscopic, and wavelength dependence of refractive index are also reported.

Novel bismuthate glasses

New bismuthate glasses have been obtained in the system Bi2O3BaOLi2O. The glass-forming region is wide and extends to fairly high Li2O content. These glasses are transparent from the visible to 9 μm. The electrical conductivity of the glass increases with Li+ ion concentration and a relatively high conductivity, 3.5 × 10−8 S cm−1, was obtained at room temperature.