Sodium-Ion Conductivity and Humidity-Sensing Properties of Na2O-MoO3-P2O5 Glass-Ceramics

A series of glass-ceramics were prepared by heat-treatments of 40Na2O-30MoO3-30P2O5 (in mol%) glass in a temperature range from 380 (Tg) to 490 °C (Tc) and for 1–24 h. The prepared glass-ceramics contain from 2 to 25 wt.% of crystalline NaMoO2PO4. The sodium-ion conductivity in these materials decreases up to one order of magnitude with an increase in the degree of crystallization due to the immobilization of sodium ions in crystalline NaMoO2PO4. The transport of sodium ions in these materials occurs primarily through the dominant continuous glassy phase, and it is weakly affected by the sporadically distributed crystalline grains. However, the prepared glass-ceramics exhibit high proton conductivity in a humid atmosphere and remarkable humidity-sensing properties; this could be related to crystalline NaMoO2PO4, which provides sites for water adsorption. The glass-ceramic prepared at 450 °C for 24 h shows the best humidity-sensing performance among all samples, showing an increase in proton conductivity for more than seven orders of magnitude with the increase in relative humidity from 0% to 95%. Under a highly humid atmosphere (95% relative humidity and 25 °C), the proton conductivity of this glass-ceramic reaches 5.2 × 10−3 (Ω cm)−1. Moreover, the electrical response of these materials on the change in the relative humidity is linear and reversible in the entire range of the relative humidity, which indicates that they are novel promising candidates for application as humidity sensors.

Structure and magnetic properties of Bi-doped calcium aluminosilicate glass microspheres

Bi-doped CaO–Al2O3–SiO2 glass microspheres with Ca2Al2SiO7 (gehlenite) composition were prepared by combination of solid-state reaction and flame synthesis. The concentration of Bi was 0.0, 0.5, 1 and 3 mol %. The chemical composition of prepared glass microspheres was determined by X-ray fluorescence (XRF). The structural and magnetic properties of prepared glass microspheres and their polycrystalline analogues were studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Raman spectroscopy and SQUID magnetometry. The closer inspection of glass microspheres surface by SEM confirmed smooth surface and revealed no features indicating presence of crystalline phases. All Bi-doped microspheres are X-ray amorphous, however in case of undoped microspheres XRD detected traces of crystalline gehlenite. XRD analysis of samples crystallized at 1273 K for 10 h revealed the presence of gehlenite as the main crystalline phase. The presence of gehlenite in crystallized samples were also confirmed by Raman spectroscopy. All samples (glass microspheres and their crystalline analogues) showed diamagnetic or weak ferromagnetic behavior at room temperature, whereas paramagnetic or weak ferromagnetic behavior was observed at 2 K.

Impact of Al2O3 and Dy2O3 Substitution on the Physical, Structural, and Radiation Shielding Properties of Li2O-B2O3 Glass System

A new series of lithium-borate glass systems (23Li2O-72B2O3 in mol%) were synthesized with the substitution of Al2O3 (5 mol.%) as a modifier and doped with 0.3 and 0.5 mol% of Dy2O3. Four series of glasses (S1, S2, S3 and S4) were synthesized via the conventional melt-quenching technique and characterized by using UV-Visible-NIR absorption spectrometer and Fourier transform infrared (FTIR) spectroscopy. The current investigation gives further insight on the structural and optical properties of the samples. The diffraction spectrum obtained from the X-ray Diffraction (XRD) analysis shows no typical peaks in the glass system, which indicates its amorphous phase. The optical properties of Al3+ and Dy3+ ions were evaluated and found that there is a pivot effect for the addition of Al2O3 and Dy2O3 for the glass system. Notably, the sample S2 shows different behaviours for physical, structural, and optical properties compared with other prepared glass samples that can be attributed to the increment of Al2O3. Besides, the physical and ionizing shielding features were investigated for current glass samples. The radiation shielding properties were examined within the energy range of 0.015 until 15 MeV. The sample S4 has the optimum radiation shielding features as a result of the addition of Dy2O3. Hence, the composition attributes a new glass system that can be used in various applications such as radiation dosimeter and photon shielding materials.

Ion Capture and Release Ability of Glass Ionomer Cement Containing Nanoporous Silica Particles with Different Pore and Particle Size

This study prepared glass ionomer cement (GIC) containing nanoporous silica (NPS) (GIC–NPS) at 5 wt% concentrations using 3 types of NPS with different pore and particle sizes and evaluated the differences in their cationic ion capture/release abilities and mechanical properties. The cationic water-soluble dye was used as cationic ion. The test GIC–NPS complexes captured dyes by immersion in 1 wt% dye solutions. All the GIC–NPS complexes released dyes for 28 d, and the amount of dye released from the complexes increased with decreasing pore size; however, the particle size of NPS did not affect the amount of dye released. Additionally, GIC–NPS was able to recharge the dye, and the amount of released the dye by the complexes after recharge was almost identical to the amount released on the first charge. Although not significantly different, the compressive strength of GIC–NPS was slightly greater than that of GIC without NPS regardless of the type of NPS. These results suggest that the degree of capture and release of cationic molecules, such as drugs, can be controlled by optimizing the pore size of NPS without sacrificing its mechanical strength when its content is 5 wt%.

Comparison Study of Elastic, Physical and Structural Properties for Strontium Oxide and Manganese Oxide in Borotellurite Glasses for High Strength Glass Application

In this research the melt quenching technique method was used to synthesize two series of borotellurite glass systems doped with manganese and strontium. Elastic measurement, X-Ray Diffraction and Fourier Transform Infrared spectroscopy were used to characterize the prepared glass samples. The increment of molar volume confirmed the theory that molar volume is inversely proportional to the density parameters. A broad hump appeared in XRD as the samples shown pure amorphous nature. In FTIR, the functional group vibrations of tellurite network were recorded such as TeO4 trigonal bipyramids and TeO3 trigonal pyramids by addition of both dopants. On the other hand, ultrasonic velocity was used to determine the elastic moduli of the glass such as bulk modulus, shear modulus, longitudinal modulus, Young’s Modulus, microhardness and Poisson’s ratio which showed decreasing and increasing trends with the increased concentration of MnO2 and SrO respectively.

Glass and Glass-ceramics based on Weathered Basaltic Rock for Radiation Shielding Applications

Different batches of weathered basalt ranging from 100 to 50%, in combination with by-pass cement dust, were used to prepare the glass compositions. Different techniques used, such as differential thermal analysis, X-ray diffraction, density, FTIR, the mass attenuation coefficients, appropriate atomic number (Zeff), and effective electron density (Neff), were examined for the prepared glass and glass-ceramics samples at different photon energies.. In the present study, it was revealed that as the molar volume decreases, the density increases. The experimental and theoretical effects of the mass attenuation component were mostly consistent at different energies. Results revealed that glass samples (WB100) having a higher percentage of basaltic rocks present higher radiation protection than those with a lower rate (WB50). In addition, glass-ceramics displayed enhanced radiation and gamma rays protection than glass. Therefore, we recommend using glass ceramics containing 100% Basalt as a protective shield against rays with less thickness and higher protection.

Novel Er3+ doped heavy metals-oxyfluorophosphate glass as a blue emitter

Developed P2O5-ZnO-PbO-WO3-NaF glasses containing Er3+ ions were prepared by the melt/casting procedures. X-ray diffraction patterns confirmed the amorphicity of the prepared materials. The density and Fourier Transform Infrared FTIR spectroscopy showed that Er3+ ions play a modifier role and the studied glasses have low phonon energy. The observed decrease in the measured glass transition temperature indicates that the decrease in the bonding strength of the studied glass structure. The studied glass has a high thermal stability. Vickers microhardness results showed the weakening of the glass network. Measured UV-Vis absorption spectra exhibited several bands in the ultraviolet and visible regions. The studied glass has a high refractive index. The metallization criterion showed that the studied glasses have an insulating behavior. The metallization criterion values of the present glasses are in the range of nonlinear optical materials. Under 320 nm excitation wavelength, the studied glass generates three blue bands at 446, 457, and 473 nm. The CIE-1931 chromaticity diagram coordinates confirmed the blue emission of the prepared glass. According to the obtained results, the produced glasses have a high potential for using as efficient luminescence materials for photonic devices in the blue region.

Synthesis of Pb3O4-SiO2-ZnO-WO3 glasses and their fundamental properties for gamma shielding applications

In this research, we prepared zinc lead silicate glass system with the composition 35Pb3O4-60SiO2- (5-x) ZnO-xWO3 (0 ≤ x ≤ 5 mol %) via the melt-quench method. XRD is explored the nature of the glass system. Ultrasonic velocity, and elastic modulus were experimentally investigated and then the results were confirmed by using the theoretical calculations. It was found that because of molar volume reduction inter-ionic distance\({R}_{i}\), polaron radius \({r}_{p}\), and inter-nuclear distance, \({r}_{i}\)of the investigated glasses are reduced with WO3 content. The basic attenuation factors; mass and linear coefficients denoted by µ/ρ and µ, respectively, were determined employing several simulations for each energy via FLUKA code. As WO3 content increased from 0 to 5 mol %, the µ increased from 0.728 cm− 1 to 0.856 cm− 1 achieving high shielding performance for the sample with x = 5 mol %. At 0.6 MeV with x = 5 mol %, we found that the dose rate of the prepared glass system decreases from 2.35 × 107 R/h at 1 mm to 4.71 × 106 R/h at 4 mm. The values of MFP and HVL are lower than those of the conventional photon shields indicating that our prepared glass samples (especially G5 glass sample) have promising shielding properties to use for x/gamma rays applications.

Mono-crystalline nanometer high cristobalite glass-ceramic from nominal pyroxene glass

Transparent glass was prepared from nominal alkali pyroxene (Na2 Mg Si2O6) composition. Incorporation of Cr2O3 in alkali pyroxene composition in two % (0.5 and 1.0) increases the crystallization temperature. High cristobalite was developed alone in all glass samples heat-treated at 800°C. The microstructure shows nanometer crystals of high cristobalite which spread in glassy matrix. The densities, hardness and coefficient of thermal expansion were between 2.49 and 2.53 g/cm3, 505 and 611 kg/mm2 and between 9.38 and 13.32 x 10− 6°C− 1 (30–300 ˚C ) respectively. The antimicrobial activity of the prepared glass and ceramics shows that the only samples contain 1% of Cr2O3shows an inhibition zone in case of Candida albicans yeast.

Effect of Vanadium on Structural and Optical Properties of Borate Glasses Containing Er3+ and Silver Nanoparticles

Glass samples (59.5 – x) B2O3 – 20Na2O – 20CaO – xV2O5 – Er2O3 – 0.5AgCl (x = 0 – 2.5 mol%) were prepared using melt – quenching method to investigate the structural and optical properties of the glass. The structural of the glass were characterized by using XRD, TEM and FTIR, meanwhile the optical properties were characterized by UV – VIS absorption. The XRD patterns confirmed the amorphous nature of the prepared glass samples. FTIR confirmed the presence of VO4, VO5, BO3, and BO4 vibration, and this result showed NBO increased with increasing vanadium concentration. The UV – Vis – NIR spectra exhibits six absorption band centered at 490, 520, 540, 660, 800, and 980 nm. The optical band gap (Eopt), Urbach energy and refractive index shown decrease, increase and increase, respectively. The Judd – Ofelt intensity parameter reveal the trends was Ω2 > Ω4 > Ω6. There are three emission bands at 516 nm, 580 nm, and 673 nm which are represented by 2H11/2 – 4I15/2, 4S3/2 – 4I15/2, and 4F15/2 – 4I15/2, respectively under 800 nm excitation was obtained.