• K A ALY

      Articles written in Bulletin of Materials Science

    • Elastic and optical properties of Ge$_x$Se$_2$Sb$_{1−x}$ ($0.0\le x \le 1.0$) glasses

      K A ALY N AFIFY Y B SADDEEK A M ABOUSEHLY

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      The present study deals with the effect of composition on the elastic and optical properties of Ge$_x$Se$_2$Sb$_{1−x}$ ($0.0 \le x \le 1.0$) glasses. The various elastic moduli of these glasses such as Young’s modulus ($Y$) andthe bulk modulus ($B$) along with the micro-hardness ($H$), Poisson’s ratio ($\rho$) and Debye temperature ($T_D$) were obtained from the values of the longitudinal ($v_l$) and shear ($v_s$) ultrasonic velocities. On the basis of measurementsof the transmittance and reflectance spectra in the wavelength range of 0.4–2.5 $\mu$m the optical constants such as the film thickness ($t$), the refractive index ($n$) and the optical band gap ($E_g$) were investigated with high accuracy. The optically determined bulk modulus of these glasses was in good agreement with that elastically investigated. The obtained results were discussed in terms of the changes in the glass density, electronegativity and electronic polarizability with the variation in antimony content.

    • Fabrication and physical characteristics of new glasses from wastes of limestone and phosphorite rocks

      YASSER B SADDEEK K A ALY RABIE S FARAG M A M UOSIF K H S SHAABAN

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      In this work, new glasses were synthesized from wastes of limestone and phosphate rocks besides commercial borax. The glasses were characterized by FTIR, DTA, ultrasonic techniques and UV spectroscopy. It was found that the concentration of both CaO and P$_2$O$_5$ increases and the concentrations of B$_2$O$_3$ and Na$_2$O decrease as the content of phosphate rocks increases. Variation of the contents of the different oxides affects the concentration of the structural units constituting the glass, which was indicated by the behaviour of the fraction N$_4$ of BO$_4$ units in the borate matrix. The density and the refractive index of the glasses decrease as the CaO and P$_2$O$_5$ contents increase, which was attributed to the increase of [BO$_3$] structural units. On the other hand, the physical parameterssuch as the ultrasonic velocity, the elastic moduli, the optical bandgap and the optical polarizability increased, which was attributed to the higher coordination number of CaO$_6$ compared with the coordination of borate structuralunits and to the former effect of P$_2$O$_5$. As a result, a polymerization of the total co-ordination number of the glass, crosslink density and connectivity within the glass network will occur.

    • Linear and non-linear optical properties of amorphous Se and M5Se95 (M $=$ Ge, Ga and Zn) films

      GH ABBADY K A ALY Y SADDEEK N AFIFIY

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      The variations in structure and optical properties of amorphous a-Se and a-M$_5$Se$_{95}$ (M = Ge, Ga and Zn) films have been studied based on FTIR and optical measurements. FTIR transmittance spectra for a-Se and a-M$_5$Se$_{95}$ (M $=$ Ge, Ga and Zn) glasses were measured as a function of wavenumber. The addition of Ge, Ga and Zn increases the vibrational frequency of the a-Se main band. The absorption edge of Ge$_5$Se$_{95}$ shifted towards long side of the wavelength in comparison with that of a-Se film. This shift increases gradually in the case of Ga$_5$Se$_{95}$ and Zn$_5$Se$_95$ films. So, the optical bandgap ofM5Se95 films was decreased, but the index of refraction was increased. The first and third order of electric susceptibility ($\chi_{(1)}$ and $\chi_{(3)}$) and non-linear index of refraction ($n_2$) were increased by adding Ge, Ga and Zn into a-Se.

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