Ceramics-Silikáty 36, (4) 181 - 185 (1992) |
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REACTION MECHANISM AND KINETICS OF SrTiO3 CRYSTAL GROWTH IN MOLTEN ALKALI METAL CHLORIDES MEDIUM |
Lubyová Želmíra, Daněk Vladimír |
Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 84196 Bratislava, Czechoslovakia
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The reaction mechanism of strontium titanium oxide SrTiO₃ formation and the kinetic, of its crystal growth from the molten mixture of alkali metal chloride, in the temperature range of 700 – 900 °C and the exposition time of 1 to 90 min were studied. During the synthesis, of SrTiO₃ from the molten mixture of SrSO₄ + Na₂CO₃ + TiO₂ + KCl + NaCl the sodium titanium oxide, Na₂TiO₃, arises in the first step. Above 500 °C strontium carbonate is formed temporarily as well. The double oxide Na₂TiO₃ reacts with strontium sulphate and strontium carbonate forming the double oxide SrTiO₃. In the investigated temperature interval and the exposition time, the average diameter of the synthetized SrTiO₃ crystals was in the range of 0.08 - 0.19 μm. It was found that the SrTiO3 crystal growth at the temperatures of 800 and 900 °C and in the time interval of 1 min up to 4 h is controlled by the diffusion of Sr and Ti through the liquid phase. |
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