A simple polymer synthesis was used to successfully synthesized Zinc Oxide Nanoparticles (ZnO NPs), and the influence of the different calcination temperature on the structural, and optical properties of the material was observed using several techniques. The formation of ZnO NPs was confirmed by FT−IR, EDX, XRD, FESEM and TEM images upon calcination from 500−750 °C. The FESEM images showed the ZNO NPs synthesized possessed a hexagonal shape and tended to become larger at higher calcination temperature. The XRD and FTIR revealed the precursor to be amorphous at room temperature but transform to a crystalline structure during the process of calcination. The crystalline and particle size increase as the temperature was increased. The crystalline size was between 24−49 nm for all samples calcined at 500−750 °C. The optical properties obtained by UV−vis reflectance spectrometer have further confirmed the formation of ZnO NPs. The band gap exhibits typical ZnO wide band gap, and the values decrease with an increase in calcination temperature.

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A series of ternary tellurite based glasses [(TeO2)70 (B203)30]100-x [ZnO]x glasses with different compositions of ZnO (x= 5 to 30 wt.% in steps of 5 wt.%) have been synthesized by melt quenching method. The role of ZnO to the glasses structure was studied by IR spectroscopy. FTIR spectra revealed broad, weak and strong absorption bands in the investigated range of wavenumber from 280-4000 cm-1 which associated with their corresponding bond modes of vibration and the glass structure. The indirect optical band gap and the direct optical band gap are in the range 2.08-3.12 and 1.54-2.36 eV, respectively. A decrease in the values of energy band gap Eg may come down to the reason that the nonbridging oxygen ion content increases with increasing ZnO content and shifting the band edge to lower energies. The optical band gap and Urbach energies were calculated from the absorption spectra measured between 190 and 900 nm at room temperature. The refractive index, n of the glasses change from 1.84-2.00 while the molar refractivities decrease from 13.06 to 12.00 with the increase of ZnO in mol%.

Problem statement:This study involved an investigation to ascertain the diffusion of NiO and ZnO into the tetrahedral and octahedral sites using mechanical alloying method. The effect of mechanical alloying towards particle size was also reported. Approach: NiO, ZnO and Fe 2 O 3 precursors were mechanically alloyed to synthesis ultrafine powders of Ni 0.5 Zn 0.5 Fe 2 O 4 . Various milling times were employed to study the effect of milling time on the materials. The ultrafine powder was sampled after each milling time and further characterized using XRD to investigate the phases of the powder and the crystallite size, SEM for the morphology and TEM for particle size investigation. Results: The XRD spectra indicated the precursors reacted during milling with the diffusion of ZnO and followed by NiO into their respective crystallographic sites. SEM micrographs showed the agglomeration of powders due to high energy milling and TEM images proved the particles of the materials were of nanosize. Conclusion: It was concluded that samples prepared using mechanical alloying technique appear to be a potential method for large production due to the possible reduction of cost and also reduction of particle size against milling time.

Bismuth borate glass is of great interest in optoelectronic devices due to its low melting temperature (600-800 °C), extensive glass formation range, high refractive index ranging from 1.9 to 2.3, high physical and chemical stability, and nonlinear optical property. A systematic bismuth borate glass series in the systems of (Bi2O3)x−(B2O3)1−x have been successfully prepared by melt quenching technique over a wide range of composition (x = 35-70 mol%). Their elastic properties have been measured from their densities as well as longitudinal (VL) and shear ultrasonic wave velocities (Vs) which have been determined at room temperature by the MBS8000 Ultrasonic Data Acquisition system at a frequency of 5 MHz. The variation of ultrasonic wave velocities and elastic modulus such as longitudinal, Young's, bulk and shear modulus, Poisson's ratio, and micro hardness are discussed with respect of the Bi2O3 content.