کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1791668 1023616 2012 4 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Study on defect properties of nanocrystalline TiO2 during phase transition by positron annihilation lifetime
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
Study on defect properties of nanocrystalline TiO2 during phase transition by positron annihilation lifetime
چکیده انگلیسی

The defect properties of nanocrystalline TiO2 were investigated by positron annihilation lifetime spectroscopy (PALS) and X-ray diffraction (XRD) as a function of annealed temperature that ranged from 300 to 850 °C. Below 500 °C, the measured positron lifetimes of τ1 (200–206 ps) and τ2 (378–402 ps) revealed the existence of mono-vacancy and vacancy-clusters at grain surface and in the micro-void of intergranular region. Between 500 and 750 °C, the phase transition from anatase to rutile was probed by the variations of positron lifetime and XRD pattern. With the increasing temperature from 500 to 850 °C, the positron lifetime τ1, τ2 and its intensity I2 sharply decreased from 200 ps, 378 ps, and 60% to 135 ps, 274 ps, and 33%, respectively. The results clearly indicate that the mono-vacancy or vacancy-clusters at grain surface and micro-voids between the grains were annealed out during the phase transition.


► The defect properties of TiO2 with varying annealed temperatures were studied by PALS.
► The results have clearly indicated the places positrons annihilate in.
► Small size defects at grain surface were annealed out during phase transition.
► Even at high temperature, micro-void still exists in intergranular region of rutile.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Crystal Growth - Volume 353, Issue 1, 15 August 2012, Pages 55–58
نویسندگان
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