Study of Optical, Thermal and Mechanical Properties of Some Tellurite Glasses/

تاريخ النشر (نص حر)
2013
مدى
1 item
نوع الرسالة الجامعية
thesis(M.A.)-King Khalid University, College Science of Physics,1434.
الملخص

ellurophosphate glasses with the composition (76-x)TeO2· 9P2O5 ·15ZnO· xLiNbO3 (where x = 12.5, 25, 30 and 35 in mol %) were prepared by a melting technique. The optical properties of the glass were estimated by measuring UV-VIS spectroscopy and refractive indices at different wavelength. From the absorption edge studies, the optical energy gap (Eopt) and Urbach energy (E) had been evaluated. Nanocrystallization and crystallization kinetics of prepared glass were investigated using DTA, XRD, HRTEM and SEM techniques. It is found that glass with composition in mol% 51TeO2· 9P2O5 ·15ZnO· 25LiNbO3 had high extremely thermal stability (∆T= 189 0C at heating rate 15 K⋅min-1). The mean value of the activation energy ( ) Eg for structural relaxation increases from 165 to 203+ 2 kJ⋅mol-1. The activation energy for crystallization was found to increase from 150.5 to 298.5 + 2 kJ⋅mol-1 with the increase LiNbO3 content. The Avarmi exponents for the values were between 1.21 and 2.71 for the exothermic peak of the prepared glasses. Moreover, synthesized transparent glasses containing LiNbO3 nanoparticles have 16- 46 nm diameter were investigated by using XRD and HRTEM...