کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7902608 | 1510455 | 2014 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Reaching the ionic limit in the (1 â X)[Ca0.5-Mg0.5]O-XSiO2 pseudo binary glass system with 0.5 < X < 0.27: Glass formation and structure
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Container-less levitation techniques and CO2-laser heating were used to prepare a series of silicate glasses along the compositional join (1 â X)(0.5Ca-0.5 Mg)O-XSiO2 with X ranging between 0.50 and 0.27; thus reaching compositions beyond the orthosilicate limit (X = 0.33). Polarized and depolarized Raman spectra measured at ambient conditions for all these glasses show systematic and smooth band intensity changes with composition. Qi-species analysis of the isotropic Raman spectra shows the presence a) of bridging oxygens in all glasses studied with silica mole fractions down to X = 0.33 and b) of free oxygen at all compositions. Beyond the X = 0.33 limit, the connectivity between the SiO4 tetrahedra decreases drastically and the corresponding glass structures are characterized by isolated negatively charged “tetrahedral” SiO44 â and O2 â anions with M2 + (M = Mg, Ca) as counter cations, held together by pure Coulombic (ionic) interactions. The Boson peak appears in the low-frequency range 70-90 cmâ 1 and its polarization characteristics and frequency shifts with glass composition are pointed out and discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Crystalline Solids - Volume 383, 1 January 2014, Pages 38-43
Journal: Journal of Non-Crystalline Solids - Volume 383, 1 January 2014, Pages 38-43
نویسندگان
A. Retsinas, A.G. Kalampounias, G.N. Papatheodorou,