Vitrification of Phosphates of Nasicon-Type Structure
About: This article is published in Advanced Materials Research.The article was published on 1994-09-01. It has received 2 citations till now. The article focuses on the topics: Vitrification.
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TL;DR: In this article, the structural and physical properties of glass with formula Na 3-x Li x CaTi(PO 4 ) 3 [10(3-x) mol] were characterized by thermal analysis, density measurements, Raman and impedance spectroscopy.
Abstract: Glasses with formula Na 3-x Li x CaTi(PO 4 ) 3 [10(3-x) mol. % Na 2 O - 10x mol. % Li 2 O - 20 mol. % CaO - 20 mol. % TiO 2 - 30 mol. % P 2 O 5 ] (0 ≤ x ≤ 3) were prepared by standard melt-quenching technique, and their structural and physical properties were characterized by thermal analysis, density measurements, Raman, and impedance spectroscopy. When Na + is gradually replaced by Li + , molar volume, glass transition temperature (T g ) and ionic conductivity values decrease, pass through a minimum around the composition x = 1.5, then increase, while density values increase, pass through a maximum, then decrease. The non-linear variation of these physical properties is a result of the classical mixed alkali effect. Powder X-ray diffraction shows that crystallization of the glasses leads to the formation of a Nasicon phase for the compositions x = 0 and x = 0.5, and to a mixture of phases for the other compositions. Raman spectroscopy study shows that the glass structure contains P 2 O 7 and PO 4 groups, and short -Ti-O-Ti-O-Ti- chains , formed by TiO 6 octahedra linked to each other through corners. These chains are linked by phosphate tetrahedra to form -O-Ti-O-P-O- linkages.
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