20 بهمن 1401
داريوش سوري

داریوش سوری

مرتبه علمی: استاد
نشانی:
تحصیلات: دکترای تخصصی / فیزیک ماده چگال
تلفن:
دانشکده: دانشکده علوم پایه

مشخصات پژوهش

عنوان
Physical and thermal characterization and glass stability criteria of amorphous silver-vanadate-tellurate system at different heating rates: Inducing critical Ag2O/V2O5 ratio
نوع پژوهش مقاله چاپ شده
کلیدواژه‌ها
Amorphous materialsDifferential scanning calorimetry (DSC)Glass transitionsThermal propertiesOxygen packing density
سال
2017
مجله JOURNAL OF NON-CRYSTALLINE SOLIDS
پژوهشگران داریوش سوری

چکیده

Transition metal oxide containing glasses (TMOGs) have unique thermal properties. This work gives an insight into the thermal stability and the compositional dependence of thermal properties for the understudied glasses. Also, physical, some optical and thermal characterization of 40TeO2-(60 − x)V2O5-xAg2O glasses have been investigated in the compositional range of 0 ≤ x ≤ 50 mol%. DSC experiments were performed on powder samples with a weight of 5 mg, within the temperature range of 30–400 °C at heating rates φ = 2.5, 5, 7.5 and 10 K/min, to obtain the glass transition temperature (Tg) and crystallization temperature (Tcr). The heating rate dependence of Tg has been used to study the applicability Kissinger formula describing the glass transition, in order to determine the glass transition activation energy (Ea). Ea values show that it ranged from 563.22 kJ/mol to 268.36 kJ/mol, indicating that (in relation/justification to other thermal and structural data) less fragility and so higher thermal stability is devoted to in the case of x = 20 mol%. The previously reported optical absorption spectra and optical band gap (Eg) by the same author were used to evaluate the refractive index (n),which both Eg and n have a behavior change at critical content of x = 20 mol%, implying to a drastic structural change with increasing Ag2O. Also, the physical parameters such as density (ρ), molar volume (Vm), oxygen molar volume (VO∗), oxygen packing density (OPD), molar refraction (Rm) and metallization criterion (M) have been evaluated and discussed, showing a behavior change at x = 20 mol%. Different glass stability parameters and different criteria of fragility have been checked, which show that glass with x = 20 has the good stability among the present glasses. In brief, glass with x = 20 has relatively high thermal stability, high glass forming tendency, higher OPD and VO∗, and so lower non-bridging oxygen ions (NBOs), which show that it is suitable option and promising mate