Vaporisation studies on Sn-Te-O system by Knudsen effusion mass spectrometry: Thermodynamic properties over (SnO2+SnTe3O8) biphasic region. (March 2019)

• Record Type: Journal Article
• Authors: Trinadh, V.V.; Manikandan, P.; Jain, Ashish; Narasimhan, T.S. Lakshmi; Ananthasivan, K.
• Is Part Of: Calphad. Volume 64(2019)
• Page Start: 347
• Page End: 353
• Publication Date: 2019-03
• Subjects: Vaporisation -- KEMS -- Sn-Te-O -- Enthalpy -- Gibbs energy; Phase diagrams -- Data processing -- Periodicals; Thermochemistry -- Data processing -- Periodicals; Diagrammes de phases -- Informatique -- Périodiques; Thermochimie -- Informatique -- Périodiques; Thermodynamica; Electronic journals; 541.363
• DOI: 10.1016/j.calphad.2019.01.008
• Languages: English
• ISSNs: 0364-5916

Abstract

Abstract: Vaporisation studies along the pseudo binary line of SnO2 –TeO2 (SnTe3 O8 + SnO2 ) in the Sn-Te-O system were conducted by using Knudsen effusion mass spectrometry in the temperature range 843–968 K. SnTe3 O8 vaporises incongruently and TeO2 (g), TeO(g), Te2 (g) and O2 (g) were the neutral species observed over the equilibrium vapour. Partial pressure – temperature (p-T) relations of TeO2 (g), TeO(g), Te2 (g) over (SnTe3 O8 + SnO2 ) "two phase" region were determined in the temperature range 843–968 K. Partial pressures of O2 (g) were calculated by considering gas phase equilibrium reactions involving this species and TeO2 (g), TeO(g), Te2 (g). Using the p-T relations, enthalpy changes of the following reactions were evaluated: SnTe3 O8 (s) ⇌ SnO2 (s) + 3TeO2 (g); SnTe3 O8 (s) + 2TeO(g) ⇌ 4TeO2 (g) + 0.5 Te2 (g) + SnO2 (s) and 0.5Te2 (g) + TeO2 (g) ⇌ 2TeO(g). Subsequently, the enthalpy and Gibbs energy of formation of SnTe3 O8 phase at 298.15 K were deduced as Δf H m ° = −1613.7 ± 67.8 kJ mol −1 and Δf G m ° = −1386.7 ± 67.8 kJ mol −1 . Knudsen effusion mass spectrometric studies on this system are being reported for the first time.