Addition Of BaO Research Articles

Fabrication of novel BaO–Al2O3–Bi2O3–B2O3 glass system: Comprehensive study on elastic, mechanical and shielding properties

The influence of barium oxide to the elastic and shielding properties of alumina bismuth borate glass system with the compositions (BaO)x(Al2O3)0.05 (Bi2O3)0.3 (B2O3)0.65-x where x = 0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30 mol% and classified as G1, G2, G3, G4, G5, G6 and G7 were investigated. The elastic properties of the glass system were examined by bulk density, molar volume, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and non-destructive ultrasonic velocity measurement. The experimental results show that the density of the glass sample increase and molar volume of the glass sample was decrease. The XRD analysis revealed that the glass sample shows the characteristics of the amorphous nature without any sharp lines or peaks while the FTIR revealed the major broad absorption bands for borate glass structure. The ultrasonic velocities and elastic moduli measurement shows an increasing trend with the addition of BaO. The mass attenuation coefficient (MAC) demonstrated that the presence of BaO enhances the MAC values, resulting in an improvement in the shielding competency of the fabricated glasses. The highest interactions between photons and the atoms of the glasses occur around 0.122 MeV, and the glass samples have an excellent blocking capacity to photons, according to the effective atomic number (Zeff) data. Furthermore, the half value layer (HVL) revealed that when the BaO level in the composition increases, the HVL values will reduces. As a conclusion, the radiation shielding factors revealed that G7 glass with 30 mol% of BaO is the optimum performance of the produced samples.

Optical Properties according to BaO Addition for BaO-GeO2-La2O3-ZnO System

Optical Properties according to BaO Addition for BaO-GeO2-La2O3-ZnO System

Morphological, optical, structural, mechanical, and radiation-shielding properties of borosilicate glass–ceramic system

This study explores the morphological, optical, structural, mechanical, and radiation-shielding properties of borosilicate glass–ceramic samples modified with titanium oxide and various ratios of barium oxide. The morphology of the glass–ceramic system was investigated using scanning electron microscopy (SEM). The mechanical properties, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) were used to identify the fabricated sample structures. The optical properties were calculated to define the refractive index and band gap (Eg). The shielding properties were obtained by Monte Carlo simulation (MC) and compared with XCOM software data. Glass samples were converted to glass–ceramic samples at 800 °C for 6 h, and the GC25 and GC30 samples were converted to completely crystalline phases as illustrated by the XRD, FTIR, and Raman results, unlike the GC15 and GC20 samples. The XRD results showed the trigonal structure of BaB2TiO6 with the R-3 space group for the GC25 and GC30 samples and the tetragonal phase of TiO2 with the P42/mnm space group for the GC15 and GC20 samples. The sharp FTIR and Raman spectrum peaks affirm the crystal phase for G25 and G30 samples. The parent glass of the GC20 sample showed the highest mechanical moduli (Young's, bulk, shear, and longitudinal) and Poisson ratio. Concurrently, the addition of BaO instead of B2O3 caused a gradual reduction in the packing factor, dissociation energy, and microhardness. The Phy-X program was used to theoretically assess the shielding properties. The obtained results showed the highest compatibility between the Monte Carlo N-particle (MCNP) and XCOM software results, and the GC30 sample displayed the highest shielding properties due to adding BaO instead of B2O3. The crystalline phase and shielding features of the samples were improved by increasing the BaO ratio, indicating that the current samples are suitable for radiation-shielding applications.

Investigation on the structure and viscosity of BaO-bearing slag melt through molecular dynamics simulation, Raman and 27Al MAS NMR spectra

• BaO addition made the coordination numbers (CNs) of Al-O decreased. • The polymerization degree of slag increased based on the compensation effect. • The competitive action of Ba 2+ and O 2– determined the structure and viscosity. Studying the structure and viscosity of BaO-bearing slag was helpful for explaining the micro mechanism of its physicochemical property variations, and further guiding the utilization of bearing-barium ores for hot metal production. The structure of CaO-SiO 2 -10 wt% MgO-12 wt% Al 2 O 3 -BaO slag with BaO content varying from 0 to 5 wt% was studied based on the combined computational-experimental method, including the molecular dynamic (MD) simulation and experimental measurements of Raman spectroscopy and 27 Al magic angles pinning nuclear magnetic resonance ( 27 Al MAS-NMR) spectroscopy. The viscosity of the slag was measured, and the relationship between the viscosity and polymerization degree of the slag was established. MD simulation results indicated that the coordination numbers (CNs) of Si-O kept unchanged. The concentrations of four-coordinated Al units and bridged oxygen increased with an increase in BaO. The distribution of Q i units of Si and Al indicated that the structural units tended to be more complicated with the increasing BaO content. The result from Raman spectroscopy indicated that the amount of Q 2 and Q 3 units increased with the addition of BaO, while that of Q 0 and Q 1 units decreased. The results from 27 Al MAS-NMR spectroscopy showed that the relative concentration of [AlO 4 ] structural units increased from about 48 to 53 wt%, and an opposite trend was observed in [AlO 5 ] and [AlO 6 ] units, indicating that higher BaO content enhanced the polymerization degree of the slag. In addition, the viscosity of the slag increased with the rising BaO content, which was caused by the dominant effect of Ba 2+ .

Effect of multiphase flux with BaO addition on phosphorus partition

It is important to clarify the effect of BaO in phosphorus partition of multiphase flux. In current work, the slag CaO-SiO2-FetO-P2O5 with different contents of BaO was cooled from 1873 K to 1673 K to investigate the effect of BaO on phosphorus partition of solid solution. The phosphorous partition between the solid solution phase and liquid phase was obtained. In order to further inspect the effect of BaO on phosphorus partition, the experiment of reaction between 2CaO · SiO2 (C2S)-FetO/Fe2O3-BaO slag and hot metal was carried out. Furthermore, the CaO-FetO slag was also studied to compare the dephosphorization effect to C2S-FetO/Fe2O3-BaO slag. The phosphorus partition ratios Lp between the slag and hot metal were obtained. The result showed that when the slag CaO-SiO2-FetO-P2O5-BaO with various BaO content was cooled down from 1873 K to 1673 K, the solid solution was precipitated, and the enrichment of phosphorus in solid solution phase was improved with the addition of BaO. The phosphorus element content in solid solution increased from 4.16% to 5.27% with the increasing of BaO content in slag from 0 to 15% at the interval of 5%. Based on the experiment of reaction between slag and hot metal, the phosphorus content in hot metal showed that the barium ion was more beneficial to enrichment of phosphorus and the function of BaO was promoted by the addition of Fe2O3. The phosphorus partition ratio Lp between the slag C2S-FetO-BaO and hot metal was 295.38, which was higher than 208.24 that without BaO. The phosphorus partition ratio Lp between the slag CaO-FetO and hot metal was 217.50. The phosphorus partition ratio Lp between the slag C2S-Fe2O3-BaO and hot metal was 418.75, higher than that of the slag C2S-FetO-BaO.

CERAMICS BASED ON FLUORINATED TALC

A dense-sintered protoenstatite ceramics based on fluorinated talc was obtained. Influence of BaO and Al2O3 additives on the sinterability, structure and strength of ceramics was investigated. It makes possible to reduce the sintering temperature to 1225 – 1250 °C due to formation of glassy phase. Additive of ZnO intensifies solid phase sintering at 1320 °C. It significantly improves compressive strength of ceramics up to 660 MPa that exceeds the strength of traditional steatite materials by 3 times.

Investigation into the dephosphorization of ferromanganese alloys for the production of advanced high-strength steel

Advanced high-strength steels (AHSS) are sophisticated materials being developed by the steel industry to mitigate challenges related to the performance of motor vehicles. To meet the requirements of AHSS, the ferromanganese alloys (FeMn) utilized in the production of the steel are required to contain acceptable levels of unwanted impurities, i.e. P, S, N, H, and C. The focus of the current study was to investigate dephosphorization of ferromanganese to produce a low-P alloy that could be effectively utilized in the production of AHSS. The study involved conducting laboratory-scale testwork to study the efficiency of CaO-based slag systems to dephosphorize FeMn alloys. The addition of Na2O, CaF2, and BaO to MnO-CaO-SiO2 slag was considered. The test work was carried out in a 25 kW induction furnace at temperatures of 1350°C, 1400°C, and 1450°C. The P partition coefficient (Lp) remained small at <1, which is an indication that dephosphorization had not been achieved. The baseline slag, comprising 40%CaO-40%SiO2-20%MnO, reported higher Lpvalues. Addition of Na2O and CaF2 did not show any further benefit. Substituting half of the CaO by BaO, resulted in similar Lpvalues to those of the baseline slag under conditions of 1350°C and 1450°C at 30 minutes. In summary, based on the Lpvalues obtained, the conditions investigated with the CaO-based slags appeared to have been unfavourable for dephosphorization of FeMn alloys, as most of this impurity element remained in the alloy.

Optical and gamma ray shielding properties BaO doped K2O-TiO2-P2O5 glasses

The optical and gamma ray shielding characteristics of (20-x) K2O-xBaO-30TiO2-50P2O5 glasses were shown to be affected by the addition of BaO. The optical band gap energy are increases, refractive index shows a small decrement with addition of BaO in the phosphate-based glasses. With the substitution of BaO, the two parameters, molar refractivity and molar electronic polarizability are both decreased. Reflection loss (RL) is known to range from about 0.171 to 0.153, whereas transmission (T) is reported to fall between 0.7078 and 0.7339. When BaO is added to the oxide ion matrix, the polarizability of the oxide ions increases. The manufactured glass systems have a metallisation of less than one, suggesting that they are non-metallic in nature. The linear attenuation coefficient (LAC) of the tested glasses is investigated between 0.0395 MeV and 0.411 MeV. The LAC values also follow the order of KBTP20 > KBTP15 > KBTP10 > KBTP5 > KBTP0. The glass with composition of 20 BaO-30 TiO2-50 P2O5 has the greatest LAC. The effective atomic number of the KBTP10 sample is equal to 36.66 at 0.0395 MeV, and decreases to 35.35, and 12.27 at 0.0395 MeV and 0.4111 MeV, respectively. The half value layer values at 0.1218 MeV lies within 0.564 and 1.644 cm. The results proved that increasing the BaO content in the glass system leads to more desirable radiation shielding properties for the samples.

Viscosity and structure evolution of CaO–SiO2–MgO–Al2O3–BaO slag with the CaO/SiO2 mass ratio of 0.9

Keeping a low and steady viscosity of slag is conducive to smooth operation of blast furnace. In this work, the effect of BaO on the viscosity and structure evolution of CaO–SiO2–MgO–Al2O3–BaO slag with a fixed CaO/SiO2 mass ratio of 0.9 was studied. The results revealed that the viscosity decreased firstly with BaO content rising from 0 wt% to 1.0 wt%, and then increased with further improving BaO content, which was ascribe to the contradictory effect of Ba2+ and O2− on the aluminate–silicate network structure. The structural analysis by Fourier transform infrared spectroscopy (FTIR) and Raman spectra showed that a small amount addition of BaO could promote the transformation from Q2 and Q3 units toward Q0 and Q1 units. However, the higher BaO content would induce an increasing concentration of Q2 and Q3 units, leading to an enhancement of the polymerization degree of slag. In addition, the variations of Al-related structural units were identified by the 27Al magic angle spinning nuclear magnetic resonance (27Al MAS-NMR) spectra. The relative fraction of [AlO4] units firstly decreased and then increased with the addition of BaO, and an opposite trend was observed for [AlO5] and [AlO6] units. The structural analysis supported the results of viscosity experiment well.

Optical properties and frequency-dependent conductivity of K2O-BaO-TiO2-P2O5 glasses

The glass compositions (20-x)K2O-xBaO–30TiO2–50P2O5 with (0 ≤ x ≤ 20 mol%) were elaborated using the conventional quenching method. Their related glass-ceramics were developed by controlled crystallization under heat treatments. UV–visible absorption was employed to study the optical properties of the glasses. This technique showed the reduction of Ti4+ to Ti3+ ion content with the substitution of K2O by BaO, and it was found that the BaO addition reduces the structural disorder in the studied glasses. The electrical properties of the glass-ceramics were carried out by impedance spectroscopy in the frequency range from 10 Hz to 1 MHz under various temperatures from room temperature to 550 K. The obtained results showed that the electrical conductivity follows Jonscher’s universal power law and the electrical motion process in the glass-ceramics is provided by the hopping mechanism.

Femtosecond laser induced thermophoretic writing of waveguides in silicate glass

Here in, the fs-laser induced thermophoretic writing of microstructures in ad-hoc compositionally designed silicate glasses and their application as infrared optical waveguides is reported. The glass modification mechanism mimics the elemental thermal diffusion occurring in basaltic liquids at the Earth’s mantle, but in a much shorter time scale (108 times faster) and over a well-defined micrometric volume. The precise addition of BaO, Na2O and K2O to the silicate glass enables the creation of positive refractive index contrast upon fs-laser irradiation. The influence of the focal volume and the induced temperature gradient is thoroughly analyzed, leading to a variety of structures with refractive index contrasts as high as 2.5 × 10–2. Two independent methods, namely near field measurements and electronic polarizability analysis, confirm the magnitude of the refractive index on the modified regions. Additionally, the functionality of the microstructures as waveguides is further optimized by lowering their propagation losses, enabling their implementation in a wide range of photonic devices.

Effects of BaO on crystallization, structure and dielectric properties of MgO–Al2O3–SiO2 glass–ceramics for LTCC applications

Cordierite-based glass–ceramics for LTCC applications were prepared by traditional sintering method. And the effects of BaO addition on the crystallization, structure and dielectric properties were investigated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffractometer (XRD), dilatometer and impedance instrument. The DSC curves displayed that the glass transition temperature (Tg) slowly decreased with the BaO content increasing from 0 to 4 mol%. However, the onset of crystallization temperature (Tx) and crystallization peak temperature (Tc) showed the opposite trend. XRD analysis revealed that μ-cordierite was the major crystal phase for all the glass–ceramic samples, while α-cordierite precipitated as the minor crystal phase with BaO addition. As more BaO was added, the bulk density gradually increased, while the porosity decreased, indicating that BaO improved the sinterability of the glass samples. The dielectric constant showed minimum value with the addition of 2 mol% BaO, and the dielectric loss reached the minimum value when the content of BaO was 3 mol%. Wherein, after heated at 950 °C, glass–ceramics doped with 2 mol% BaO showed a dense structure, a relatively low dielectric constant (4.53), a low dielectric loss (2 × 10−3) at 1 MHz, and a proper CTE value (3.74 × 10–6/°C), which can be used to prepare LTCC materials.

Effects of BaO and B2O3 on the Absorption of Ti Inclusions for High Titanium Steel

In order to study the effect of BaO or B2O3 on the absorption of Ti inclusions, the effects of mold fluxes with different contents of BaO (0~15%) or B2O3 (0~15%) on the mass transfer coefficients of TiO2 or TiN were studied with the rotating cylinder method. The experimental results show that with the addition of BaO in the mold flux, the mass transfer coefficient of TiO2 increases from 4.58 × 10−4 m/s to 6.08 × 10−4 m/s, that of TiN increases from 3.09 × 10−4 m/s to 4.41 × 10−4 m/s, 2CaO·MgO·2SiO2 is transformed into BaO·2CaO·MgO·2SiO2, and the Ti inclusions combine with CaO to form CaTiO3. With the addition of B2O3 in the mold flux, the mass transfer coefficient of TiO2 increases from 4.58 × 10−4 m/s to 7.46 × 10−4 m/s, that of TiN increases from 3.09 × 10−4 m/s to 5.50 × 10−4 m/s, CaO and B2O3 combine to 2CaO·B2O3, and Ti inclusions exist in the form of TiO2. During the experiment, TiN will be transformed into titanium oxide.

Influence of BaO on the catalytic properties and durability of Pd-CZLA for automobile exhaust

Co-precipitation was used to prepare CeO2-ZrO2-La2O3 (CZL) support, and impregnation was employed to load nano-aluminum sol and Pd to prepare a Pd-CZLA catalyst that can be directly used in car exhaust pipe for the secondary purification of exhaust gas. The specific surface area of the catalyst can reach 143.2 m2/g. At 400 0 C, the catalytic efficiency of the catalyst was 76.47%, 70.59%, and 75.41% for C3H8, CO, and NOx, respectively. After modification through doping with 8% BaO in nano-alumina, the catalyst has enhanced high-temperature stability and maintained its high catalytic activity after aging at 1100 0 C. Scanning electron micrograph showed that the high-temperature sintering of the catalyst is slowed down when modified by BaO addition. Combined barium oxide and nano-alumina acts as a stabilizer that prevents the crystalline phase transition of alumina at high temperature and further stabilizes its structure. This material also stabilizes Pd dispersion and improves CZA supportive protection at high temperature.

Structural and radiation shielding features for a new series of borate glass samples: part I

In this work, five glass samples with a composition (80 − x) B2O3–10ZnO–10CdO–x BaO, where (x = 10, 15, 20, 25, and 30 mol%), were fabricated by a standard melt-quench method. The current glass composition structure was explored via Fourier transform infrared (FTIR) and X-ray diffraction (XRD). XRD pattern proves an absence of sharp peaks, affirming the amorphous nature of the prepared samples. FTIR spectrum within the range of 1650–400 cm−1 clarifies the functional groups’ existence and the variation in BO3 and BO4 with the addition of BaO. The obtained results show a direct relationship between the density and the BaO contents. In contrast, the relation between the BaO and Poisson’s ratio and packing density is inverse. The supplement of BaO to the glass system gradually drove to a slight reduction in glass stability. Furthermore, the mass attenuation coefficient (μ/ρ) was defined experimentally by using two sources (137Cs and 166Ho) with five energies (0.184, 0.280, 0.661, 0.710, and 0.810 MeV). This range of energy can be used in nuclear medicine fields. The excellent agreement between experimental and XCOM values is evident. Based on the experimental results, several radiation shielding properties, including linear attenuation coefficient, effective atomic number (Zeff), half-value layer, mean free path, and tenth value layer, were computed. The results indicate that the sample G5 has a superior photon shielding competence compared with other standard shielding materials. Lastly, it can conclude that the prepared glasses may be used in different sectors as a radiation shielding material.

Effect of the Ba/K ratio on structural, dielectric and energy storage properties of BaO–K2O–TiO2–P2O5 glass-ceramics

xBaO–(20−x)K2O–30TiO2–50P2O5 with (0≤x≤20 mol%) glasses were successfully elaborated by the melt quenching while their related glass-ceramics were developed by controlled crystallisation. Density and molar volume measurements, differential thermal analysis and Raman spectroscopy were carried out to examine the glassy structure, the results revealed that the addition of BaO increases the reticulation and reinforces the glass network by the creation of strengthened linkages. X-ray diffraction has identified the formation of MTi2(PO4)3 with M=(K, Ba0·5) in all the glass-ceramics (GC) and the precipitation of a secondary BaTiP2O8 phase when x increase beyond 10 mol%. The dielectric properties of the glass-ceramics were studied by impedance spectroscopy, it showed that the addition of BaO induces an enhancement of both thermal and frequency stability of the dielectric parameters (εr and tanδ). The glass-ceramic with 5 mol% of BaO GC-(x=5) presents the highest dielectric constant and the lowest dielectric loss. The P-E hysteresis loops were recorded at room temperature and the energy storage parameters of the glass-ceramics were determined. These parameters were significantly improved by the increase of the BaO content and the optimum parameters were obtained for GC-(x=5). The dielectric and energy storage parameters were discussed according to the structure data.

Effect of BaO on lead free zinc barium tellurite glass for radiation shielding materials in nuclear application

In this study, the zinc barium tellurite glasses (ZBaT) synthesized and inspected their radiation defensive mechanism and structural behavior. Glass composition (90-x) TeO2 - 10 ZnO - xBaO, where 25≤ x ≤ 35 (mol%) was prepared using the melt quenching technique and glass-forming pseudo-ternary diagram was discussed. Addition of BaO enhances the polarization in the present glasses there by it increases the bond length hence glass network expands resulting in volume. The mass attenuation coefficient (μm) of ZBaT glasses have been evaluated at various energies via Compton scattering technique. The results found that the μm, effective atomic number and effective electron density decrease with the increase in γ-ray energies which is in a good agreement with theoretical values attained using Geant4 and WinXCOM. At 25 mol% BaO content the glass samples show less mean free path (MFP) which were compared with other standard shield defensive materials. The obtained results reveal that the formation of non-bridging oxygens increased with higher concentration of BaO. The transmission spectra of the prepared glasses displayed optical light transparency thereby demonstrating their efficient role being transparent window when used as radiation defensive material without Pb component proving them as eco-friendly for environment.

Investigation of photon, neutron and proton shielding features of H3BO3–ZnO–Na2O–BaO glass system

The current study aims to explore the shielding properties of multi-component borate-based glass series. Seven glass-samples with composition of (80-y)H3BO3–10ZnO–10Na2O–yBaO where (y = 0, 5, 10, 15, 20, 25 and 30 mol.%) were synthesized by melt-quench method. Various shielding features for photons, neutrons, and protons were determined for all prepared samples. XCOM, Phy-X program, and SRIM code were performed to determine and explain several shielding properties such as equivalent atomic number, exposure build-up factor, specific gamma-ray constants, effective removal cross-section (ΣR), neutron scattering and absorption, Mass Stopping Power (MSP) and projected range. The energy ranges for photons and protons were 0.015–15 MeV and 0.01–10 MeV, respectively. The mass attenuation coefficient (μ/ρ) was also determined experimentally by utilizing two radioactive sources (166Ho and 137Cs). Consistent results were obtained between experimental and XCOM values in determining μ/ρ of the new glasses. The addition of BaO to the glass matrix led to enhance the μ/ρ and specific gamma-ray constants of glasses. Whereas the remarkable reductions in ΣR, MSP, and projected range values were reported with increasing BaO concentrations. The acquired results nominate the use of these glasses in different radiation shielding purposes.

Effects of BaO on the Viscosity and Structure of a New Fluorine-Free CaO-Al2O3-TiO2-Based Mold Flux for High Titanium Steel

Herein, the effects of BaO (i.e. 5, 10, 15 and 20 pct) on the viscosity and structures of a new fluorine-free CaO-Al2O3-TiO2-based mold flux with w(CaO pct)/w(Al2O3 pct) ratio of 1.0 are investigated using a rotary viscometer, molecular dynamics (MD) simulations, and Raman spectroscopy. The viscosity of the samples (the testing temperature is 1300 °C) decrease from 0.46 to 0.21 Pa·s as the BaO content increased from 5 to 20 pct, and the activation energy decreases from 150.7 to 119.7 kJ·mol−1, the break temperature (Tbr) decreases from 1475 K to 1429 K which are achieved as the initial testing temperature of 1300 °C decreased under the furnace cooling. With the addition of BaO, the MD simulation results suggest that the coordination numbers (CNs) of Al (Ti)-O are reduced, while Q3, Q4, and Q5 are depolymerized into Q0, Q1, and Q2. The Raman spectroscopy results illustrate that the bridge oxygens (BOs) originating from the Ti-O-Ti (Al) linkages and Q2 (Al-O−) are depolymerized into Q1 (Si-O−) and Q0 (Al-O−) as the BaO content is increased. The Raman spectroscopy results agree well with those of the MD simulation. Therefore, BaO can simplify the structure of melts and decrease the viscosity of such systems. This work not only presents a new fluorine-free CaO-Al2O3-TiO2-based mold flux, but also deepens the understandings of the role of BaO in this system.

The crystallization and structure features of glass within the K2O–MgO–CaO–Al2O3–SiO2-(BaO) system

The effect of the BaO addition on the microstructure and structure of the glasses from the K2O–MgO–CaO–Al2O3–SiO2-(BaO) system was investigated in this study. The results were obtained by testing the crystallization capability of the glasses during the fast-firing cycle. Thermal analysis proved a high tendency to crystallize the tested glasses/frits. X-ray analysis showed the presence of diopside and anorthite as the main crystalline phases in all glazes obtained from the tested glasses. Microscopic observations showed that barium oxide introduced in the range of 0.4–2.1 mol% into the examined system strongly influences the number and size of crystalline phases. The introduction of 2.1 mol% BaO into the composition also resulted in crystallization of celsian. The thermal characteristic of the glasses was carried out using differential scanning calorimetry (DSC) and the crystalline phases were determined by X-ray diffractometry. The glaze microstructure was investigated by scanning (SEM) and transmission electron (TEM)microscopy. Additional information on the structure of frits was derived from mid-infrared (MIR) and Raman spectroscopy.