Pb-free Glasses Research Articles

Mechanical and radiation shielding properties of tellurite glasses doped with ZnO and NiO

This study examines the basic mechanical parameters and radiation shielding properties of (100−x)TeO2+xZnO+4NiO glasses (where x = 9.6, 19.2, 28.8, and 38.4 mol%) glass system. The mechanical study included basic parameters such as hardness, packing density, elastic moduli, and Poisson's ratio. Shielding ability of the glasses was tested against gamma and neutron radiations as well as against charged particles such as electron, proton, and alpha. Geant4 simulations and theoretical calculations by using Phy-X computer program were carried out to estimate mass attenuation coefficient (μ/ρ), neutron removal cross section (RCS), transmission factors namely; half value layer (HVL) and mean free path (MFP), and effective atomic number for total interaction of gamma (Zeff-G), electron (Zeff-E), proton (Zeff-P), and alpha (Zeff-A) radiations. The results showed that ZnO concentration had a significant influence on the mechanical properties and the shielding capability for glasses involved. The values effective atomic number were in the range of 30.2–46.1 for Zeff-G, 21.2–26.5 for Zeff-E, 16.9–19.7 for Zeff-P, and 15.3–18.6 for Zeff-A, respectively. The current glasses can act as superior shielding material as compared with those of Pb-free glasses, commercial glasses, and traditional concrete.

Gamma-ray and neutron shielding efficiency of Pb-free gadolinium-based glasses

The radiation shielding efficiency of material depends upon photon attenuation, exposure buildup factors and neutron removal capacity. A newly developed Pb-free gadolinium-based glasses in compositions (80-x) B2O3-10SiO2-10CaO-xGd2O3 (where x = 15, 20, 25, 30 and 35 mol%) had completely been investigated for their shielding efficiency with Geant4 simulation for mass attenuation coefficients and neutron total macroscopic cross section and by calculating exposure buildup factors. The exposure buildup factors for photon energy from 0.015 to 15 MeV had been calculated up to 40 mean free paths using five factors geometric progression method. The mass attenuation coefficients of the Pb-free glasses were simulated for energies from 223 to 2614 keV and compared with the possible available experimental results. The neutron shielding efficiency of these glasses was discussed by calculating neutron total macroscopic cross section for energies from 1 eV to 14.1 MeV. Present investigations are found to be very useful for applications in nuclear engineering.

Synthesis and Optical Properties of Tb-doped BaO$_{3}$-B$_{2}$O$_{3}$-Li$_{2}$O Pb-free Glasses

Synthesis and Optical Properties of Tb-doped BaO$_{3}$-B$_{2}$O$_{3}$-Li$_{2}$O Pb-free Glasses

Synthesis and Physical Properties of Rare-earth-doped Pb-free Glasses

Synthesis and Physical Properties of Rare-earth-doped Pb-free Glasses

Thermal properties of glasses based on Bi2O3 for Pb free solder glasses

With the aim of developing Pb-free Bi2O3-based new solder glasses; glass forming region, glass transition temperature, crystallization temperature, thermal expansion, and water resistance of Bi2O3-BaO-B2O3 ternary glass system were investigated. The roles of Bi2O3 in this ternary glass were also discussed. The results showed that glass transition temperature and thermal expansion coefficients of the ternary glasses were in similar range as compared to those solder glass consisting PbO. The water resistance of ternary glass was almost the same as compared to window glass, but it is higher than solder glass containing PbO. The glass transition temperature of ternary glass was dependent on average bond strength. Our results also showed that as the amount of Bi2O3 increased, the average bond strength was decreased which lead to decrement of glass transition temperature. These results suggested that Bi2O3 plays an important role as glass network former in the glass system.

Physical and dielectric properties of BaTiO3–fluoride–glass systems for nitrogen-fireable embedded capacitors

BaTiO3-based dielectrics containing the selective additive combinations from Pb-free glasses and fluoride compounds such as AlF3, BaF2, CaF2, LiF and ZnF2 were studied mainly for a potential N2-fireable embedded capacitor in printed circuit board with Cu metallization. The physical and dielectric properties, such as dielectric constant (k), loss tangent (tanδ) and Tc, strongly depended on the choice of additive combination. A bismuth borosilicate glass was most promising in terms of the degree of densification and dielectric constant. The samples containing LiF and ZnF2 and sintered at 950 °C looked most beneficial in that these additives produced high k of >1,200 and low tanδ of < 0.022 at room temperature regardless of sintering atmosphere. As an example, the 95BaTiO3–2LiF–3(Bi borosilicate) sample exhibited k ~ 1,340 and tanδ ~ 0.022 at room temperature when fired at 950 °C in N2.

Etching Mechanism of Pb-Free Glasses in Acid Solution for Barrier Ribs in Plasma Display Panel

We present the preliminary results of our research on the behavior of lead free glasses in the acid etching process, which is used for the formation of barrier ribs in plasma display panel. The glasses (BaO-B2O3-ZnO system) were etched in HNO3 solution (0.1-1.0% HNO3) at 50°C. The structure and surface of the etched bulk glass were investigated by using inductively coupled plasma and X-ray photoelectron spectroscopy. As a result, Ba (3-35ppm/min) and Zn (2- 27ppm/min) ions as major components were leached in the solution. A decrease of the bridge oxygen and a relative increase of non bridge oxygen in the etched glass were found by X-ray photoelectron spectroscopy.