کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1480696 | 1510420 | 2015 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Water- and boron speciation in hydrous soda-lime-borate glasses
ترجمه فارسی عنوان
آب بندی و استخراج بور در عینک آبی-لیمو بورات آبی
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کلمات کلیدی
ساختار شیشه، عینک های آبدار فشار بالا، طیف سنجی،
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
چکیده انگلیسی
The structural investigation of hydrated borate glasses provides new insights on the influence of water on boron speciation using spectroscopic methods. In the present study three soda-lime-borate glasses (NCBx with x = 5, 15 and 25 corresponding to xNa2O, 10CaO, 90 â xB2O3 in mol%) were prepared with water content up to 8 wt.%. The water speciation in the glasses was derived by near-infrared (NIR) spectroscopy while boron speciation was investigated by 11B MAS NMR (Magic Angle Spinning Nuclear Magnetic Resonance). For the three glasses effective molar absorption coefficients were determined experimentally for the bands at 5200 cmâ 1 and 4600 cmâ 1, corresponding to combination modes of H2O molecules and OH-groups, respectively. In contrast to silicate glasses, in which at most ~ 2 wt.% H2O are dissociated to OH-groups, the amount of dissociated H2O may even exceed 5 wt.% in borate glasses. The fraction of tetrahedral to total boron (N4 = BIV / BIV + BIII) is predominantly controlled by the ratio of Na2O + CaO / B2O3, but only weakly affected by the water content of the glasses. When increasing the H2O content from 0 to 8 wt.%, N4 increases from 25% to 26% for NCB5 and from 42% to 47% for NCB25 glasses.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Crystalline Solids - Volumes 423â424, 1 September 2015, Pages 58-67
Journal: Journal of Non-Crystalline Solids - Volumes 423â424, 1 September 2015, Pages 58-67
نویسندگان
U. Bauer, H. Behrens, M. Fechtelkord, S. Reinsch, J. Deubener,