Effect Of Sm2O3 Research Articles

Effect of Sm2O3 on thermal, optical, mechanical, gamma and neutron shielding properties of zinc-boro-vanadate glasses

Abstract The effect of Sm2O3 on thermal, optical, mechanical, gamma and neutron shielding properties of newly prepared zinc borovanadate glasses has been investigated. Density is found increased and molar volume decreased with Sm2O3 content. The glass transition temperature ( T g ) , crystallization temperature ( T c ) and the peak crystallization temperature ( T P ) increased with increase of rare earth oxide content. These findings demonstrated an excellent glass-forming ability and thermal stability of the glasses. The optical properties have been explored through UV–vis spectroscopy. The indirect optical band gap energy ( E opt ) decreased from 2.978 to 2.679 eV, Urbach energy ( ∆ E ) increased from 0.273 to 0.299 eV and refractive index increased from 2.403 to 2.489 with increase in Sm2O3. Elastic moduli, Poisson’s ratio, Hardness and fractal bond connectivity were computed theoretically as per Makishima Mackenzie model. It is found that these glasses have appreciable mechanical strength and rigidity. Phy-X/PSD software has been used to determine different radiation shielding characteristics for the energy range 0.015–15 MeV. The mass and linear attenuation coefficients are found higher, and half value layer, tenth value layer and mean free paths are found lower than many radiation shielding glasses quoted in the literature values. The obtained Z eq values varied from 15.828–29.118 for energy range from 0.015 to 15 MeV, which are greater than those reported for several commercial glasses, concretes and rocks. Due to the Compton scattering process, exposure build up and energy absorption factor are found to be highest in the medium energy region. The fast neutron removal cross-sections of the glasses are observed to be significantly high. For the first time, thermally stable and mechanically strong zinc borovanadate glasses mixed with Sm2O3 have been thoroughly investigated for various properties and concluded that these glasses are suitable for optoelectronics and γ-shielding applications.

Effects of Sm2O3 and TiO2 on the performance of MgAl2O4-Si3N4 ceramics for solar thermal absorber in concentrating solar power

Aiming to further improve the properties of novel MgAl2O4-Si3N4 ceramic used as solar thermal absorbing material in concentrating solar power, effects of Sm2O3 and TiO2 on performance of the composites were investigated especially the mechanisms of different additives on microstructure and high temperature stability. The results show that both additives can accelerate sintering, reduce sintering temperature, improve the density and high temperature stability via liquid phase sintering mechanism. Besides, TiO2 can form displacement solid solution with Al2O3 to promote the sintering process. Sm2O3 is more conducive to improving the bending strength due to its function of increasing the length diameter ratio of β-Si3N4. TiO2 is more favorable for improving solar absorption owing to the distinctive absorption spectrum and large number of cation vacancy caused by substitution of Al3+ by Ti4+. MgAl2O4-Si3N4 composites with Sm2O3 and TiO2 additives have better performance than MgAl2O4-Si3N4, Si3N4 and SiC ceramics prepared via the same procedure, which makes it a certain choice for solar thermal absorbing material.

Enhancement of Gamma-Ray and Neutron Shielding Properties of TeO2-Li2O-ZnO-Nb2O5 Glass System with the Addition of Sm2O3

Radiation shielding glass is widely used, as it protects people from ionizing radiation while allowing for the observation of irradiated areas. However, the performance of even the best-performing tellurite glass for radiation shielding still falls short compared to traditional radiation shielding materials. The effect of Sm2O3, with a high atomic number and cross section with neutron, on the gamma-ray and neutron shielding properties of a 75TeO2-5Li2O-10ZnO-(10-x)Nb2O5-(x)Sm2O3 glass system is studied in this work. Some critical shielding parameters, including linear attenuation coefficients, half-value thickness, tenth-value layer, and mean free path (MFP), have been calculated with the software Phy-X/PSD. Two kinds of gamma-ray buildup factors, the exposure buildup factor and the energy absorption buildup factor, have been calculated in the range of 0.015 to 15 MeV for depths up to 40 MFP. What’s more, their neutron shielding ability has been evaluated by calculating the neutron total effective removal cross section. It is shown that Sm2O3 promotes the gamma-ray and neutron shielding performance of the 75TeO2-5Li2O-10ZnO-10Nb2O5 glass system. The results indicate that the addition of Sm2O3 can be helpful for the radiation shielding performance of tellurite glass, which provides a practical way for designing glass with ideal shielding properties.

Effects of Sm2O3 and Gd2O3 in poly (vinyl alcohol) hydrogels for potential use as self-healing thermal neutron shielding materials

This work investigated the mechanical, self-healing, and thermal neutron shielding properties of poly (vinyl alcohol) (PVA) hydrogels with the addition of varying samarium oxide (Sm2O3) or gadolinium oxide (Gd2O3) contents from 0 to 10.5 wt% in 3.5 wt% increments, prepared using a freezing/thawing method. The results showed that the addition of Sm2O3 and Gd2O3 fillers could greatly enhance the thermal neutron shielding properties of the PVA hydrogels, in which Gd2O3/PVA hydrogels had slightly higher neutron shielding efficiencies than Sm2O3/PVA hydrogels at the same filler content and thickness. Additionally, both the Sm2O3/PVA and Gd2O3/PVA hydrogels showed autonomously self-healing capabilities at damaged/fractured surfaces, with the healing time and filler content affecting the recoverable strength of the self-healed specimens. In terms of mechanical properties, increasing the Sm2O3 or Gd2O3 contents resulted in the increases of tensile modulus and tensile strength but the decrease in elongation at break of the hydrogels, in which Gd2O3/PVA hydrogels showed higher overall tensile properties than Sm2O3/PVA hydrogels at the same filler contents. In summary, the overall properties suggested that Sm2O3/PVA and Gd2O3/PVA hydrogels presented potentials to be utilized as self-healing thermal neutron shielding materials, in which the materials could be applied as a replacement of paraffin in transport casks or as a patient's shielding biomaterial used during medical diagnosis and radiotherapy.

Electrical properties and luminescence properties of 0.96(K0.48Na0.52)(Nb0.95Sb0.05)\u20130.04Bi0.5(Na0.82K0.18)0.5ZrO3-xSm lead-free ceramics

In this paper, Sm-doped 0.96(K0.48Na0.52)(Nb0.95Sb0.05)–0.04Bi0.5(Na0.82K0.18)0.5ZrO3 (abbreviated as KNSN–0.04BNKZ) lead-free piezoelectric ceramics were prepared by conventional solid-state sintering method and the effects of Sm2O3 on the phase structure, microstructure, electrical and luminescent properties of KNSN–0.04BNKZ potteries were studied. Results revealed that a single solid solution phase with pseudo-cubic perovskite structure was formed between KNSN–0.04BNKZ and Sm2O3. Existence of weak dielectric/ferroelectric properties with a diffuse dielectric anomaly and slim P–E hysteresis loops of the Sm-doped KNSN–0.04BNKZ demonstrated the ferroelectric relaxor behavior of the KNNS–0.04BNKZ–xSm ceramics. Accordingly, the temperature stability and fatigue behavior of the modified ceramics were significantly improved. It was found that the KNSN–0.04BNKZ ceramics with 0.002 mol Sm addition exhibited nearly temperature independent properties and fatigue-free behavior. Moreover, Sm-modified KNSN–0.04BNKZ exhibits a bright photoluminescence with a strong orange emission under visible light irradiation. As a material with both electrical and luminescent properties, it has good application prospect in future optoelectronic components by integrating its luminescent and electrical properties.

Effects of Sm2O3 and V2O5 Film Stacking on Switching Behaviors of Resistive Random Access Memories

: In this work, the resistive switching characteristics of resistive random access memories (RRAMs) containing Sm2O3 and V2O5 films were investigated. All the RRAM structures made in this work showed stable resistive switching behavior. The High-Resistance State and Low-Resistance State of Resistive memory (RHRS/RLRS) ratio of the RRAM device containing a V2O5/Sm2O3 bilayer is one order of magnitude higher than that of the devices containing a single layer of V2O5 or Sm2O3. We also found that the stacking sequence of the Sm2O3 and V2O5 films in the bilayer structure can affect the switching features of the RRAM, causing them to exhibit both bipolar resistive switching (BRS) behavior and self-compliance behavior. The current conduction mechanisms of RRAM devices with different film structures were also discussed.

The effect of Sm2O3 on the microstructure and electrical properties of SiO2-doped SnO2-Zn2SnO4 ceramic varistors

In this work, Sm2O3- and SiO2-codoped SnO2-Zn2SnO4 ceramic varistors were prepared through traditional ceramic processing, and the effect of Sm2O3 on the resulting microstructure and electrical properties was investigated. The results demonstrated that the ceramics were composed mainly of SnO2 and Zn2SnO4, and Sm was distributed homogeneously in the grains and along the grain boundaries. With 0.2mol% Sm2O3 doping, the grain growth was obviously promoted. Further increases in Sm2O3 to 0.4mol% resulted in trace amount of SiO2 and segregations containing elemental Sm via X-ray diffraction patterns and microstructure photos, respectively. In the sample doped with 0.3mol% Sm2O3, optimal electrical characteristics of α=9.4, EB=10V/mm, JL=46μA/cm2 and ε′=1.2×104 were obtained. Simultaneously, the sample doped with 0.3mol% Sm2O3 had the lowest conductance activation energy of 0.16eV at temperatures lower than 110°C. This good performance indicates that Sm2O3- and SiO2-codoped SnO2-Zn2SnO4 composite ceramics are viable candidate for the manufacture of capacitor-varistor functional devices.

Effect of Sm2O3 on microstructure, thermal shock resistance and thermal conductivity of cordierite-mullite-corundum composite ceramics for solar heat transmission pipeline

Cordierite-mullite-corundum composite ceramics for solar heat transmission pipeline were fabricated via pressureless sintering at a low sintering temperature with added Sm2O3. The effects of Sm2O3 on sintering behaviors, mechanical property, phase transformation, microstructure, thermal shock resistance and thermal conductivity of the composite ceramics were investigated. TEM analysis results demonstrated that Sm3+ located in glass and grain boundaries to facilitate the densification via the liquid-phase sintering mechanism and improve bending strength by grain refinement, respectively. Proper addition (3wt%) of Sm2O3 could promote the crystallization of cordierite, and improve thermal shock resistance of the composite ceramics with an increasing rate of 16.70% for bending strength after 30 thermal shock cycles (air cooling from 1100°C to RT). The composite ceramics possessed a superior thermal shock resistance, where a large amount of particles were formed to suppress crack initiation and propagation during thermal shock. Cordierite-mullite-corundum composite ceramics with proper Sm2O3 addition (3wt%) had a lower thermal conductivity than that of composite ceramics without Sm2O3 addition by strengthening the scattering of phonon, which could reduce the heat loss during solar heat transmission process.

Influence and effectivity of Sm2O3 and Cr3C2 grain growth inhibitors on sintering of WCoB–TiC based cermets

With WC, TiB2 and Co powders as raw materials, WCoB–TiC based cermets were prepared by liquid phase reaction sintering (LPRS) in a vacuum furnace at 1400°C. In this work, the consolidation of WCoB–TiC based cermets with Sm2O3 or Cr3C2 as grain growth inhibitor was studied. The amounts of inhibitor are 0; 0.3; 0.6 and 0.9wt%. The effects of Sm2O3 and Cr3C2 on the grain growth of WCoB–TiC based cermets were studied. The microstructure and mechanical properties of WCoB–TiC based cermets were analyzed by field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). It is found that that Sm2O3 and Cr3C2 not only retard the densification of the WCoB–TiC based cermets, but also significantly suppress the growth of WCoB-grains and TiC-particles. Specimens doped with 0.3wt% Sm2O3 exhibit the optimum mechanical properties (hardness and wear resistance). Whereas mechanical properties (hardness and wear resistance) of specimens linearly increase with the increase of Cr3C2.

Effect of Sm2O3 on structural and thermal properties of zinc fluoroborate glasses

Glasses based on Sm3+ doped zinc fluoroborate were synthesized and characterized. Formations of glasses were investigated in the 30ZnF2–20TeO2–(50–x)B2O3–xSm2O3 matrix. Fast quenching and adequate heat treatment are required to prevent melt crystallization and to diminish thermal stress, which result in an efficient amorphous material. The differential scanning calorimetry (DSC), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray photoelectron spectroscopy (XPS) were employed to record, calculate, measure and analyze the stability, density and refractive index of the glass samples with different concentrations of Sm3+ ranging between 0 to 2.5% (mass fraction). XPS result shows the values of core-level binding energy (Zn 3s, Sm 4d, Te 3d, B 1s, O 1s and F 1s) of (ZnF2–TeO2–B2O3–Sm2O3) glass matrix and indicates the good fusibility of the present glass samples. Density of the glass samples increases as dopant concentration increases and glass transition temperature tg ranges between 395 °C and 420 °C.

Good temperature stability and fatigue-free behavior in Sm2O3-modified 0.948(K0.5Na0.5)NbO3–0.052LiSbO3 lead-free piezoelectric ceramics

The rare-earth oxide Sm2O3-doped 0.948(K0.5Na0.5)NbO3–0.052LiSbO3 (abbreviated as KNN-LS5.2) lead-free piezoelectric ceramics were prepared using conventional solid sintering method. The effects of Sm2O3 on the phase structure, electrical properties, temperature stability and fatigue behavior of KNN-LS5.2 ceramics were systematically studied. Results showed that Sm2O3 substitution into KNN-LS5.2 induced a phase transition from coexistence of orthorhombic and tetragonal phase to a pseudocubic phase with a normal-relaxor ferroelectric transformation, and correspondingly shifted the polymorphic phase transition (PPT) below room temperature. Accordingly, the temperature stability and fatigue behavior of the modified ceramics were significantly improved. It was found that the KNN-LS5.2 ceramics with 0.6mol% Sm2O3 addition exhibited nearly temperature independent properties and fatigue-free behavior, together with its good electrical properties (d33*=167pm/V, d33=120pC/N, kp=33%, Qm=101, ϵr=1326, tanδ=4.6%). The results suggest that this material should be an attractive lead-free material for piezoelectric applications.