Activity of TiO2 in the system ZrO2-TiO2 and Gibbs energy of formation of ZrTiO4

K. T. Jacob, Saji Viswanathan, Y. Waseda

Research output: Contribution to journalJournal articlepeer-review

5 Scopus citations

Abstract

The activity of TiO2 in single and two-phase regions of the system ZrO2-TiO2 has been measured using solid state cells based on yttria-doped thoria (YDT) as the solid electrolyte at 1373 K. The cells used can be represented as: Pt, Ti0.07Pt0.93 + Zr1-xTixO2 / YDT / TiO2 + Ti 0.07Pt0.93, Pt Pt, Ti0.07Pt0.93 + Zr1-xTixO2 + ZrTiO4 / YDT / TiO 2 + Ti0.07Pt0.93, Pt In each cell the composition of Pt-Ti alloy was identical at both electrodes. The emf of the cell is therefore directly related to the activity of TiO2 in oxide phase or oxide phase mixture: αTiO2 = exp (-4FE/RT). The activity coefficient of TiO2 in the zirconia-rich solid solution with monoclinic structure (0.02 ≥ XTiO2 ≥ 0) can be expressed as: ln γTiO2 = 3.145 (1 - XTiO2)2 - 0.338 In the zirconia-rich solid solution with tetragonal structure (0.085 ≥ X TiO2 ≥ 0.03), the activity coefficient is given by: ln γTiO2 (± 0.012) = 2.354 (1 - XTiO2) 2 + 0.064 The standard Gibbs energy of formation of ZrTiO4 is -5650 (± 200) J/mol at 1373 K.

Original languageEnglish
Pages (from-to)203-208
Number of pages6
JournalHigh Temperature Materials and Processes
Volume25
Issue number4
DOIs
StatePublished - 2006
Externally publishedYes

Fingerprint

Dive into the research topics of 'Activity of TiO2 in the system ZrO2-TiO2 and Gibbs energy of formation of ZrTiO4'. Together they form a unique fingerprint.

Cite this