Synthesis and crystal chemical evolution of fresnoite powders

Journal Article · Thu Mar 15 00:00:00 EDT 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2011.12.031· OSTI ID:22012055

Madhavi, S ^[1]; Phonthammachai, N ^[2]

---

1. School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)
2. Institute of Materials Science and Engineering, 3 Research Link, Singapore 117602 (Singapore)

(Ba,Sr){sub 2}TiSi{sub 2}O{sub 8} fresnoite powders were prepared via a Pechini process in which citric acid and ethylene glycol were used as complexing agents. The resulting gel contained a homogeneous distribution of the metal ions that suppressed the formation of (Ba,Sr)TiO{sub 3} perovskite as a secondary phase during calcination. Phase development was examined as by isochronal and isothermal reaction analysis. A combination of thermo- and differential gravimetric analysis (TGA-DGA), quantitative X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed that calcination at 900 Degree-Sign C/12 h yielded finely crystalline ({approx}70 nm) Ba{sub 2}TiSi{sub 2}O{sub 8} (BTS) and Sr{sub 2}TiSi{sub 2}O{sub 8} (STS). The endmembers and compositional intermediates crystallized directly from the Pechini resin and indirectly through reaction of (Ba,Sr)CO{sub 3}, (Ba,Sr)TiO{sub 3} and a silica-rich glass intermediates. This new method for preparing fresnoite yields materials suitable for consolidation as dense monolithic dielectrics or for use as high surface area catalytic powders. - Graphical abstract: The Pechini synthesis of (Ba, Sr){sub 2}TiSi{sub 2}O{sub 8} titano-silicate fresnoites delivers finely divided precursors for applications as diverse as solid electrolytes and photocatalysis that exploit the unique Ti-O and Si-O bonding and structural morphology of these materials. Highlights: Black-Right-Pointing-Pointer A Pechini method for synthesizing (Ba,Sr){sub 2}TiSi{sub 2}O{sub 8} fresnoites is demonstrated. Black-Right-Pointing-Pointer The method minimizes a persistent glassy intermediate phase. Black-Right-Pointing-Pointer The Pechini process is generally applicable for tailoring fresnoites as functional materials.

• OSTI ID: 22012055
• Journal Information: Journal of Solid State Chemistry, Vol. . 187; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CALCINATION
CITRIC ACID
DIELECTRIC MATERIALS
FOURIER TRANSFORM SPECTROMETERS
FOURIER TRANSFORMATION
GLYCOLS
INFRARED SPECTRA
PEROVSKITE
PHOTOCATALYSIS
POWDERS
RESINS
SILICA
SILICATES
SOLID ELECTROLYTES
SURFACE AREA
SYNTHESIS
THERMAL GRAVIMETRIC ANALYSIS
TITANATES
TITANIUM OXIDES
X-RAY DIFFRACTION