# Investigation of Phosphate Glasses with the General Formula $A_xB_yP_30_{12}$ where A = Li, Na or K and B = Fe, Ga, Ti, Ge, V or Nb

Sobha, KC and Rao, KJ (1996) Investigation of Phosphate Glasses with the General Formula $A_xB_yP_30_{12}$ where A = Li, Na or K and B = Fe, Ga, Ti, Ge, V or Nb. In: Journal of Non-Crystalline Solids, 201 (1-2). pp. 52-65.

 PDF Investigate.pdf Restricted to Registered users only Download (987kB) | Request a copy

## Abstract

Physical and thermal properties, crystallization behaviour and dc conductivity of glasses with the general formula $A_xB_yP_30_{12}$ where A is an alkali ion and B = Fe, Ga, Ti, Ge, V or Nb have been investigated. Glasses of compositions $A_3B_2P_3O_{12}$, $A_5BP_3O_{12}$ and $A_4BP_3 0_{12}$ have been prepared by quenching the melts. Molar volumes of these glasses change considerably on inter alkali substitution (by 30-40% on going from Li to K). The glass transition temperatures are within the small range of 30 K for the Li, Na and K members, except in the vanadium containing glasses. The glasses with B = Fe, Ti or Ge are found to crystallize immediately above the glass transition temperature. Iso-compositional crystallization was observed in $Na_3Fe_2P_30_{12}$. The DSC crystallization exotherms are often not simple, indicating stages of crystallization. Crystallization kinetics of the $Na_3Fe_2P_30_{12}$ glass reveal a lower activation energy for isothermal crystallization than for the non-isothermal crystallization. The dc conductivities estimated from impedance plots are in the range of $10^{-9}\omega^{-1},cm^{-1}$to $10^{-7}\omega^{-1}cm^{-1}$ at 298 K and the conductivity activation energies are in the range 0.5-0.8 eV, with no variation between $Li^+$ and $K^+$ containing glasses, greater than errors of measurement.

Item Type: Journal Article Copyright of this article belongs to Elsevier. Division of Chemical Sciences > Materials Research Centre nazneen khan 21 Nov 2006 13 Apr 2011 07:32 http://eprints.iisc.ac.in/id/eprint/8396