Enthalpy of formation and thermodynamic insights into yttrium doped BaZrO3

Autor(es)

Goncalves, M. D. ^{[1, 2, 3]} ; Maram, P. S. ^{[2, 3]} ; Muccillo, R. ^[1] ; Navrotsky, A. ^{[2, 3]}

Afiliação do(s) autor(es)

^[1] Energy & Nucl Res Inst, Ctr Sci & Technol Mat, BR-05508900 Sao Paulo - Brazil

^[2] Univ Calif Davis, NEAT ORU, Davis, CA 95616 - USA

^[3] Univ Calif Davis, Peter A Rock Thermochem Lab, Davis, CA 95616 - USA

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF MATERIALS CHEMISTRY A; v. 2, n. 42, p. 17840-17847, NOV 14 2014.
• Citações Web of Science: 15

Resumo

The enthalpies of formation from binary oxide components at 25 degrees C of Ba(Zr1-xYx)O3-delta, X = 0.1 to 0.5 solid solutions are measured by high temperature oxide melt solution calorimetry in a molten solvent, 3Na(2)O center dot 4MoO(3) at 702 degrees C. The enthalpy of formation is exothermic for all the compositions and becomes less negative when increasing yttrium content from undoped (-115.12 +/- 3.69 kJ mol(-1)) to x = 0.5 (-77.09 +/- 4.31 kJ mol(-1)). The endothermic contribution to the enthalpy of formation with doping content can be attributed to lattice distortions related to the large ionic radius difference of yttrium and zirconium and vacancy formation. For 0.3 <= x <= 0.5, the enthalpy of formation appears to level off, consistent with an exothermic contribution from defect clustering. Raman spectra indicate changes in short range structural features as a function of dopant content and, suggests that from x = 0.3 to 0.5 the defects begins to cluster significantly in the solid solution, which corroborates with the thermodynamic data and the drop-off in proton conductivity from x > 0.3. (AU)

• Processo FAPESP: 13/10928-0 - Medidas calorimétricas de entalpias de superfície e de interfaces em zirconato de bário dopado com ítrio
• Beneficiário: Mayra Dancini Gonçalves
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 11/50197-0 - Caracterizacao de zirconato de bario dopado com itrio, sintetizado pelo metodo dos peroxidos oxidantes.
• Beneficiário: Mayra Dancini Gonçalves
• Modalidade de apoio: Bolsas no Brasil - Doutorado