Study of Some Physical Properties of Nanocrystallized Glass-Ceramic /

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

ulticomponent semiconducting oxide glasses within composition (80-x)V2O5· 20Bi2O3· xBaTiO3 with x = 2.5, 5, 7.5 and 10 mol % were prepared by melt-quenching technique at a temperature of 1050 °C for 30 minute. The density and molar volume were measured for glass samples, also the Vickers hardness was measured for glasses and glass- ceramic samples. It was found that the density and Vickers hardness increase with increasing BaTiO3 content, but molar volume decreases with increasing BaTiO3 content. The crystallization behavior and the nanostructure of the glasses were investigated by using non-isothermal differential scanning calorimetric (DSC), XRD, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mean value of the activation energy of structural relaxation ( ) Eg decreases from 395 to 369 kJ/mol when BaTiO3 increasing from 2.5 to 10 mol %. The activation energies for crystallization obtained by the methods Kissinger and Ozawa were in the range 213 – 256 kJ/mol. Different analysis methods were used to estimate the Avrami exponents. theirs values are in the range 4.26 to 2.62 for the exothermic peak of the prepared glasses. Moreover, synthesized glass-ceramics which containing BaTi4O9, Ba3TiV4O15 nanoparticles have been 25 – 35 nm and 30 – 46 nm respectively, were...