Synthesis and characterization of Li2O modified sodium phosphate glasses | ||
| Journal of Scientific Research in Science | ||
| Article 6, Volume 35, part 1, August 2018, Pages 417-438 PDF (1.41 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jsrs.2018.25524 | ||
| Authors | ||
| H. Zayed* 1; M. E. Sayed2; M. M. Elokr3; L. I. Soliman4 | ||
| 1Physics Department, Faculty of Women, Ain Shams University, Cairo, Egypt | ||
| 2Physics Department, Modern Academy for Engineering and Technology in Maadi, Cairo, Egypt | ||
| 3Physics Department, Faculty of Science, Al-Azhar University, Cairo, Egypt | ||
| 4National Research Center, Dokki, Cairo, Egypt | ||
| Abstract | ||
| The transparent glasses 55 P2O 5 - (45-x) Na2O - xLi2O where (x=0, 3, 10, 15, 30, 35) were prepared by conventional melt quenching technique. Structural and characterization have been investigated by using X-Ray diffraction (XRD) and the results show that all samples are amorphous structure. The glass transition (Tg) and crystallization temperature (Tc) are evaluated using the differential thermal analyzer (DTA), which indicate that 15 mol% Li2O contained glasses exhibits maximum thermal stability h’ of glass samples. Density, molar volume and oxygen packing density insure that Li2O incorporated in sodium phosphate glass by increasing Li2O content. The ac and dc electrical conductivity and dielectric constants of the prepared glass samples have been investigated. The variation of dc conductivity with the concentration of Li2O mol% passes through a maximum at 15 mol% Li2O. Temperature dependence of the dc conductivity of these glasses is found to obey the Arrhenius law. It reveals that the values of activation energies ΔEdc1 and ΔEdc2 at low and high temperatures lie in the range 0.452-0.93 eV. Also it was found that the values of σdc to be the same as the values obtained from the impedance study. Conductivity mechanism for grain resistance at room temperature was discussed using Cole-Cole plot. To determine the conduction mechanism, the ac conductivity and its frequency exponent have been analyzed by correlated barrier hoping model (CBH). It was found that the exponent (s) has values between 0.62-0.9; consequently the (CBH) seems to be the most interesting model related to the obtained results. The variation of dielectric constants ε’ and ε’’ with the concentration of Li2O mol% pass through a maximum at 15 mol% Li2O and this result would be discussed by means of dielectric polarization mechanism of material. The maximum value of the maximum barrier height Wm obtained from Guitini equation was found to increase with increasing of Li2O mol%. | ||
| Keywords | ||
| Sodium Phosphate glass; Thermal analysis; electrical conductivity | ||
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