An Investigation into the Effects of Composition and BaF2 Content on the Structure and Crystallization Behavior of SiO2-Al2O3-K2O-BaF2 Oxyfluoride Glasses
Nowadays, oxyfluoride glasses have received much attention from photonic researchers as they benefit from the advantages of both oxide and fluoride glasses (low phonon energy in parallel with high mechanical and chemical durability). The purppose of this paper was to study the different glass compositions in SiO2-Al2O3-K2O-BaF2 system and investigate the BaF2 effects on their crystallization behavior and structure. Therefore, various chemical compositions with different amounts of BaF2 (20, 30, and 40mol%) were chosen and melted in alumina crucibles at 1450˚C. The sample could not melt with the lowest percentage of BaF2. On the other hand, the glass composition containing the highest amount of BaF2 was not able to show high transparency due to the phase separation that occurred in it. Finally, the sample with a 30mole ratio of BaF2 was chosen as the optimized sample due to the favorable transparency. XRD patterns showed that the samples were amorphous and it somehow proved the low transparency in the presence of higher amounts of BaF2 arose from phase separation than the unwanted crystallization. According to the DTA results, the crystallization peak of the fluoride phase decreased from 693˚C to 678˚C by increasing the content of BaF2. FT-IR spectra approved the oxyfluoride structure of the glasses. Higher BaF2 content increased the absorption of peaks in FT-IR spectra since it results in a more discontinuous structure. Fluorine loss was higher for the glass containing the highest amount of BaF2 due to the lower amount of Al2O3 in its composition.
Comparison of Semiconducting Behavior and Optical Properties of Oxyfluoride Glasses of SiO2-Al2O3-BaF2 and SiO2-Al2O3-CaF2 Systems
Amorphous semiconductors are materials with a brilliant prospect for a wide range of optical applications like solar cells, optical sensors, optical devices, and memories. The purpose of the present research was to study the semiconducting optical properties of SiO2-Al2O3-CaF2 and SiO2-Al2O3-BaF2 oxyfluoride...متن کامل
The interdiffusion coefficients of barium and fluoride in glasses, in the system Na2O/K2O/Al2O3/SiO2 with BaF2 additions, were determined from the diffusion profiles using energy dispersive X-ray analysis in a scanning electron microscope. The diffusivities were in agreement with Arrhenius-equation. Diffusion coefficients of fluoride were in the range from 4.5 10 15 m s 1 to 30 10 15 m s 1 at 5...متن کامل
an investigation into the impact of m-game-enhanced blended module of teaching and learning on iranian students english literacy skills and subskills learning
پژوهش حاضر با پیوند رسانه های قدیمی و جدید یاد دهی و یادگیری _طرح داستان و بازی های همراه ــ در یک پو دمان ترکیبی، در صدد قیاس شیوه ی یاد دهی و یادگیری مبتنی بر بازی مهارت های فرعی و اصلی واژگان، خواندن و نوشتار سواد انگلیسی با شیوه های مرسوم آن بود. به این منظور با کاربرد یک طرح سه گانه همراه با الگوی نظام آموزشی (تومی، 2010)، بازی های از پیش ساخته شده و بومی قابل عرضه از طریق ارتباطات سیّار (ب...
an inverstigation into the shrinkage behavior (kinetics) of microfilled hybrid and nano dental composites
چکیده ندارد.15 صفحه اول
an investigation of the impact of self monitoring on langauge teachers motivational practice and its effect on learners motivation
the central purpose of this study was to conduct a case study about the role of self monitoring in teacher’s use of motivational strategies. furthermore it focused on how these strategies affected students’ motivational behavior. although many studies have been done to investigate teachers’ motivational strategies use (cheng & d?rnyei, 2007; d?rnyei & csizer, 1998; green, 2001, guilloteaux & d?...
the effects of planning on accuracy and complexity of iranian efl students’ written narrative task performance
this study compared the different effects of form-focused guided planning vs. meaning-focused guided planning on iranian pre-intermediate students’ task performance. the study lasted for three weeks and concentrated on eight english structures. forty five pre-intermediate iranian students were randomly assigned to three groups of guided planning focus-on-form group (gpfg), guided planning focus...15 صفحه اول
دوره 6 شماره 1
صفحات 16- 21
تاریخ انتشار 2020-03-01
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