Effect of SiCw Whiskers on the indentation thermal shock resistance of ZrB2-MoSi2 Composites

A comparative evaluation of the thermal shock resistance (TSR) of ZrB2-20 MoSi2-20 SiCw (ZMSw20) and ZrB2-20 MoSi2 − 5SiCw (ZMSw5) composites were studied using the indentation quench method. High-dense ZrB2 based composites were prepared by multi-stage spark plasma sintering at 1700°C. The results show that the ZMSw20 composite expressed superior crack shielding and TSR under quenching circumstances. The critical temperature differential ΔTc of ZMSw20 ceramic (ΔTc= 800°C) was higher than that of ZMSw5 ceramic (ΔTc=600°C). The significant enhancement in TSR was imposed residual stresses that improved the resistance to crack progression during thermal shock. Furthermore, an increment in silicon carbide content reduces the crack growth, and increases the TSR of the composites.

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.

Thermal and Crystallization Behavior of B2O3 – SiO2 – Bi2O3 – TiO2 – Y2O3 Glasses

Glasses with the chemical composition of 52B2O3 – 12SiO2- 26Bi2O3 – (10 - x ) TiO2 - xY2O3, : (0 ≤ x ≥ 10 )prepared using the melt-quench method. The goal of this study is to investigate the structural, thermal, and crystallization characteristics of these samples. XRD analysis has explored the nature of the glass system. Molar volume obtained reduced while the density denotes increased in the present system. FTIR analysis revealed that as Y2O3 replaced by TiO2, because of an increasing trend in bridging oxygens (BOs), structural units and interconnection of modifier oxide tetrahedral increment, while non-bridging oxygens (NBOs) reduce. These glasses' thermal stability investigated using DTA. As the concentration of Y2O3 increased, so the thermal parameter values. The glass-ceramic denoted prepared under controlled heat and investigated using XRD & SEM. Ultrasonic velocities and elastic moduli of glass-ceramic samples increase as internal energy increases. The significance of Y2O3 modifier in the glass system signifies proved. Y2O3 is a powerful nucleating agent that can cause crystallization, assisting in the formation of glass-ceramic phases.

Spectroscopic Properties and Dispersion Parameters of B2O3 – SiO2 – Bi2O3 – TiO2 – Y2O3 Glasses

Glasses with the chemical formula 52B2O3 – 12SiO2- 26Bi2O3 – (10-x) TiO2 - Y2O3, :(0≤ x ≥ 10), the melt-quench method was used to prepare this glass system. The purpose of this article is to investigate the spectroscopic features of these glasses. The nature of the glass system has been investigated using X-ray diffraction analysis. In the current article, the molar volume acquired decreased while the density and refractive index increased. In the current article, Y2O3 plays an important role and impacts the spectroscopic characteristics of the samples accordingly. For all the present glasses, the optical bandgap is found to be in the semiconducting range. The optical bandgap enhances as Y2O3 rises, while Urbach energy reduces. Molar Refractivity, molar polarization, polarization, and optical basicity decrease with increasing Y2O3 content. Wemple and Didomenico principles were used for calculated the Eo and Ed dispersion. The significance of the Y2O3 modifier in the glass system signifies proved.

Tunning the Crystallization Behavior of B2O3 – SiO2 – Bi2O3 – TiO2 – Y2O3 Glasses

Glasses with the chemical composition of 52B2O3 – 12SiO2- 26Bi2O3 – (10-x)TiO2 -xY2O3, :(0 ≤ x ≥10)prepared using the melt-quench method. The goal of this study is to investigate the structural, thermal, and crystallization characteristics of these samples. XRD analysis has explored the nature of the glass system. Molar volume obtained reduced while the density denotes increased in the present system. FTIR analysis revealed that as Y2O3 replaced by TiO2, because of an increasing trend in bridging oxygens (BOs), structural units and interconnection of modifier oxide tetrahedral increment, while non-bridging oxygens (NBOs) reduce. These glasses' thermal stability investigated using DTA. As the concentration of Y2O3 increased, so the thermal parameter values. The glass-ceramic denoted prepared under controlled heat and investigated using XRD & SEM. Ultrasonic velocities and elastic moduli of glass-ceramic samples increase as internal energy increases. The significance of Y2O3 modifier in the glass system signifies proved. Y2O3 is a powerful nucleating agent that can cause crystallization, assisting in the formation of glass-ceramic phases.

Effects of Fe2O3 on Reduction Process of Cr-Containing Solid Waste Self-Reduction Briquette and Relevant Mechanism

High-temperature quench method, scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), and thermodynamic analysis were adopted to study the effects of Fe2O3 on reduction process of Cr-containing solid waste self-reduction briquette (Cr-RB). Moreover, the relevant mechanism was also studied. The results clearly showed that the addition of Fe2O3 decreased the chromium-iron ratio (Cr/(Fe + Cr)) of Cr-RB itself and promoted the reduction of chrome oxide in the Cr-containing solid wastes such as stainless steel slag and dust. A large number of Fe-C alloy droplets generated in the lower temperature could decrease the activity of reduced chromium by in situ dissolution and the reduction of Cr-oxide was accelerated. Rapid separation of metal and slag could be achieved at a relatively lower temperature, which was very beneficial to the efficient recovery of Cr. Finally, the corresponding mechanism diagram was presented.

Ab initio Study of the Amorphous Cu-Bi System

ABSTRACTAs a pure element, bismuth is a semimetal which possesses several interesting physical properties, not all of them well understood. The recent discovery of superconductivity, as predicted by our group, and the increasing superconducting transition temperature as the pressure applied increases, are some examples of its particularities. Also, the fact that the amorphous phase is superconductive with a transition temperature several orders of magnitude larger than the crystalline at ambient pressure is unusual. These phenomena have also motivated our predictions for the transition temperatures of Bi-bilayers and the Bi-IV phase. When mixed with other elements, bismuth seems to contribute to the superconducting character of the resulting material. Here we study the binary copper-bismuth amorphous system which is known to superconduct in diverse compositions. Using ab initio molecular dynamics and the undermelt-quench method, we generate an amorphous structure for a 144-atom supercell corresponding to the Cu61Bi39 system. We calculate the electronic and vibrational densities of states for the amorphous system and estimate a superconducting critical temperature of 4.2 K for the amorphous state.