Thermodynamic restrictions on mechanosynthesis of strontium titanate

Journal Article · Sun Jan 15 00:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.10.044· OSTI ID:21612863

Monteiro, J F ^[1]; Ferreira, A A.L. ^[2]; Antunes, I ^[1]; Frade, J R ^[1]

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1. Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)
2. Instituto Politecnico de Viana do Castelo, 4900-347 Viana do Castelo (Portugal)

Chemical potential phase stability diagrams were calculated from relevant thermodynamic properties and used to predict the thermodynamic driving force under prospective conditions of room temperature mechanosynthesis. One analysed the dependence of chemical potential diagrams on temperature and partial pressure of evolving gases such as oxygen or carbon dioxide, as expected on using strontium peroxide or strontium carbonate as precursor reactants for the alkali earth component. Thermodynamic calculations were also obtained for changes in titania precursor reactants, including thermodynamic predictions for reactivity of strontium carbonate with amorphous titania. Experimental evidence showed that strontium titanate can be obtained by mechanosynthesis of strontium carbonate+anatase mixtures, due to previous amorphization under high energy milling. Ability to perform mechanosynthesis with less energetic milling depends on the suitable choice of alternative precursor reactants, which meet the thermodynamic requirements without previous amorphization; this was demonstrated by mechanosynthesis from anatase+strontium peroxide mixtures. - Graphical abstract: X-Ray diffractograms of the starting TiO{sub 2} (anatase)+SrCO{sub 3} mixture and after mechanical activation at 650 rpm, for 1, 2, and 7 h. Different symbols are used to identify reflections ascribed to anatase (diamonds), SrCO{sub 3} (squares) and SrTiO{sub 3} (triangles). Highlights: Black-Right-Pointing-Pointer Prediction of thermodynamic driving force for room temperature mechanosynthesis. Black-Right-Pointing-Pointer Dependence of chemical potential diagrams on temperature and partial pressure. Black-Right-Pointing-Pointer Thermodynamic calculations for changes in titania precursor. Black-Right-Pointing-Pointer Experimental support for thermodynamic predictions.

• OSTI ID: 21612863
• Journal Information: Journal of Solid State Chemistry, Vol. 185; Other Information: DOI: 10.1016/j.jssc.2011.10.044; PII: S0022-4596(11)00586-X; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON DIOXIDE
DIAGRAMS
DIAMONDS
FORECASTING
OXYGEN
PARTIAL PRESSURE
PEROXIDES
PHASE STABILITY
REFLECTION
STRONTIUM
STRONTIUM CARBONATES
STRONTIUM TITANATES
TEMPERATURE RANGE 0273-0400 K
TITANIUM OXIDES
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
CARBON
CARBON COMPOUNDS
CARBON OXIDES
CARBONATES
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
ELEMENTS
INFORMATION
METALS
MINERALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SCATTERING
STABILITY
STRONTIUM COMPOUNDS
TEMPERATURE RANGE
THERMODYNAMIC PROPERTIES
TITANATES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS