| 1. |
- Ahmad, Irshad, 1992, et al.
(author)
-
Effect of nano-Ag addition on the superconducting properties of MWCNT doped magnesium diboride superconductor
- 2024
-
In: Journal of Alloys and Compounds. - 0925-8388. ; 990
-
Journal article (peer-reviewed)abstract
- Bulk MgB2 superconductor added with nano silver (Ag), multiwalled carbon nanotube (MWCNT) and both the added (i.e., nano-Ag and MWCNT) samples were synthesized. The influence of nano-Ag and MWCNT addition on the structural and superconducting properties were studied. The XRD analysis confirms the formation of hexagonal MgB2 superconductor. Microstructural studies of all the synthesized samples are carried out by field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The superconducting properties such as critical temperature (Tc), magnetic critical current density (Jc), irreversibility field (Birr) and flux pinning properties of all the synthesized samples were investigated at 10 K and field up to 7 T. Nano Ag added MWCNT doped MgB2 shows maximum enhancement in the critical current density i.e., 5.83 × 104 A/cm2 at 5 T and 10 K.
|
|
| 2. |
- Ahmad, Zubair, et al.
(author)
-
Fine-tuning of redox-ability, optical, and electrical properties of Bi2MoO6 ceramics via lanthanide doping and rGO integration for photo-degradation of Methylene Blue and Ciprofloxacin
- 2024
-
In: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 1002
-
Journal article (peer-reviewed)abstract
- Herein, lanthanide ion (Gd+3) doped Bismuth Molybdate (Bi2MoO6) integrated on the rGO sheets has been prepared as a novel photocatalyst (Gd@Bi2MoO6/rGO) for the photocatalytic treatment of toxic pollutants. Different physiochemical, optical, electrical, thermal, and electrochemical properties of Gd@Bi2MoO6/rGO, along with its counterparts (Bi2MoO6 and Gd@Bi2MoO6) were studied through XRD, SEM/TEM, FT-IR, UV/Vis, I-V, TGA, Mott-Schottky, and EIS measurements. Photocatalytic experiments revealed that Gd@Bi2MoO6/rGO exhibited significantly enhanced photocatalytic activity, achieving 96.2 % photo-degradation of Methylene Blue with 120 min of irradiation, which is 6.5 and 3.1 times higher compared to Bi2MoO6 (40.9 %) and Gd@Bi2MoO6 (64.8 %), respectively. Moreover, Gd@Bi2MoO6/rGO demonstrated a notable photocatalytic efficiency of 81.7 % towards Ciprofloxacin, significant as per the existing literature benchmark. The enhanced photocatalytic activity is ascribed to the in-built Gd+3 redox centers, high electrical conductivity (7.35 × 10−3 S/m), favorable flat band potential (-0.81 V), and low semiconductor impedance (Rct = 51.71 Ω and Rs = 0.90 Ω). Additionally, the electron-capturing ability of lanthanide dopant ions and S-C heterojunction of Gd@Bi2MoO6/rGO facilitates the separation of photo-generated e-/h+ pairs and favors high concentrations of ROS. The results obtained highlight the potential of Gd@Bi2MoO6/rGO for applications in photocatalysis and wastewater treatment.
|
|
| 3. |
- Ahmed, Shahbaz, et al.
(author)
-
Accurate First-Principles Evaluation of Structural, Electronic, Optical and Photocatalytic Properties of BaHfO3 and SrHfO3 Perovskites
- 2022
-
In: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 892
-
Journal article (peer-reviewed)abstract
- A reliable first-principles account of experimentally observed physical properties of perovskite oxides is crucial for realizing their employment in electronic and optical devices. In this context, SCAN meta-GGA functional of DFT offers good approximation for the exchange-correlation energy; facilitating accurate determination of structural and energetic properties. However, SCAN is unable to reproduce electronic and optical properties of wide bad gap materials. In the present study, we report systematic DFT calculations to show that structural, energetic, electronic and optical properties of hafnium based BaHfO3 and SrHfO3 perovskite oxides can be accurately determined through a combine application of SCAN and Tran-Blaha modified Becke-Johnson (TB-mBJ) meta-GGAs. The structural and energetic properties computed using SCAN functional for both BaHfO3 and SrHfO3 are found to be in good agreement with experimental data; achieving a level of accuracy comparable to computationally expansive hybrid DFT calculations. On the other hand, TB-mBJ calculated band gaps computed using the SCAN optimized lattice parameters provide better agreement with experimental data at a low computational cost. The optical properties, band edge potentials and effective masses of the charge carriers in BaHfO3 and SrHfO3 are also computed to examine the combined application of SCAN and TB-mBJ meta-GGAs in predicting the photocatalytic performance of these wide band gap materials. Our results clearly show that the combination of the two meta-GGAs provide a computationally economical route for evaluating the photocatalytic performance of alkaline-earth metal hafnates.
|
|
| 4. |
- Allal, Adel, et al.
(author)
-
Structural stability, mechanical, electronic and optical behaviour of RbXS2 (X = Y and La) under high pressure : A first-principle study
- 2020
-
In: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 848
-
Journal article (peer-reviewed)abstract
- The high-pressure behaviour of the ternary sulphides, RbXS2 (X = Y and La), has been investigated by using first-principle calculations based on density functional theory. Upon applying hydrostatic pressure, the unit-cell parameters (a, c) decrease with different rates, indicating an anisotropic axial compression. The most of RbYS2 and RbLaS2 crystals compressibility comes from Rb+1-S-2 bonds. Elastic constants and their dependence on pressure and related mechanical properties have been reported and analysed. From Pugh's criterion, RbYS2 and RbLaS2 turn from brittle to ductile material for applied pressures beyond 3.1 GPa and 2.9 GPa, respectively. Stability criteria show that RbYS2 and RbLaS2 are not mechanically stable in ci-NaFeO2 crystal structure above 20.63 GPa and 16.24 GPa, respectively. Both RbYS2 and RbLaS2 have indirect band gap, which decreases with increasing pressure. However, no indirectdirect band gap transition is observed for both materials. Finally, the calculated optical spectrum of both compounds exhibits an anisotropy and a broadening at high pressures.
|
|
| 5. |
- Babizhetskyy, V., et al.
(author)
-
Investigation in the ternary Ta-Ni-P system : Solid state phase equilibria at T=1070 K, crystal and electronic structures of new ternary phosphides
- 2021
-
In: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 864
-
Journal article (peer-reviewed)abstract
- The solid state phase diagram for the ternary Ta-Ni-P system was established at T=1070 K in the region of up to 67 at% of P by means of X-ray powder diffraction methods (PXRD). Six ternary compounds, namely Ta4NiP (Nb4CoSi-type), Ta1.10-0.82Ni0.90-1.18P (TiNiSi-type), TaNiP2 (NbNiP2-type), Ta(5.00-4.81)Ni(4.00-4.19)P4 (Nb5Cu4Si4-type), TaNi2P (own structure type) and Ta1-0.08(1)Ni0.08(1)P2 (OsGe2-type) have been confirmed to exist. Rather minor Ta/Ni homogeneity ranges have been found for alpha-Ta3-xNixP (x=0.2) (Ti3P-type), Ta1-xNixP (x=0.18) (NbAs-type), Ni3-xTaxP (x=0.2) (Ni3P-type) and Ni2-xTaxP (x=0.25) (Fe2P-type). The crystal structure of Ta4.811(9)Ni4.189(9)P4 has been refined from single crystal X-ray diffraction data (Nb5Cu4Si4-type, space group I4/m, a =9.8474(17), c=3.5182(7) angstrom, R1=0.0283, wR2=0.0470), while that of the new TaNi2P compound was determined by means of PXRD. This phosphide crystalizes in its own structure type (space group Pnma, a=8.3588(3), b=3.5208(1), c=6.7051(3) angstrom, R-I=0.044, R-P=0.161). A new isostructural Fe-compound, TaFe2P (a=8.358(2), b=3.5194(7), c=6.703(1) angstrom), was also synthetized. The electronic structures of Ta5Ni4P4 and TaNi2P were analyzed using the tight-binding linear muffin-tin orbital (TB-LMTO) and extended Huckel methods.
|
|
| 6. |
- Bhardwaj, Anand, et al.
(author)
-
Auto tunable hyperthermic response of temperature sensitive magnetic fluid in agarose gel containing Mn1−xZnxFe2O4 nanoparticles
- 2024
-
In: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 978
-
Journal article (peer-reviewed)abstract
- The present study reports the synthesis and physico-chemical characterization of Mn1−xZnxFe2O4 (x = 0.5, 0.4, 0.3, 0.2, 0.1) nanoparticles-based magnetic fluids with reference to magnetic fluid hyperthermia. The properties of these fluids are studied using XRD, FTIR, TGA, VSM and the induction heating equipment operated at 330 kHz. The heating response of the fluids is investigated within the safety limit of H·f (4.8 *108 A/m-s). The study is also extended to simulate it for the agarose gel phantom system. The power absorption by these samples in distilled water and in agarose gel is calculated to compare with the experimentally observed value. To the best of the author's knowledge, no study of temperature sensitive magnetic fluid is reported on agarose gel, which simulates or phantom an in vivo condition. Results analysis show that the control of hyperthermia temperature is possible at lower fields and frequencies for the A91 sample with the smallest possible concentration, which can be acceptable for in vitro study.
|
|
| 7. |
- Broering Chaar, Ana Beatriz, et al.
(author)
-
Microstructural influence of the thermal behavior of arc deposited TiAlN coatings with high aluminum content
- 2021
-
In: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 854
-
Journal article (peer-reviewed)abstract
- The influence of the microstructure on the thermal behavior of cathodic arc deposited TiAlN coatings was studied as a function of isothermal annealing. Two compositionally similar but structurally different coatings were compared, a Ti0·34Al0·66N0.96 coating with a fine-grain structure consisting of a mixture of cubic (c) and hexagonal (h) phases, and a Ti0·40Al0·60N0.94 coating with a coarse-grain structure of cubic phase. By in situ wide-angle synchrotron x-ray scattering, spinodal decomposition was confirmed in both coatings. The increased amount of internal interfaces lowered the decomposition temperature by 50 °C for the dual-phase coating. During the subsequent isothermal anneal at 1000 °C, a transformation from c-AlN to h-AlN took place in both coatings. After 50 min of isothermal annealing, atom probe tomography detected small amounts of Al (∼2 at.%) in the c-TiN rich domains and small amounts of Ti (∼1 at.%) in the h-AlN rich domains of the coarse-grained single-phase Ti0·40Al0·60N0.94 coating. Similarly, at the same conditions, the fine-grained dual-phase Ti0·34Al0·66N0.96 coating exhibits a higher Al content (∼5 at.%) in the c-TiN rich domains and higher Ti content (∼15 at.%) in the h-AlN rich domains. The study shows that the thermal stability of TiAlN is affected by the microstructure and that it can be used to tune the reaction pathway of decomposition favorably.
|
|
| 8. |
- Bullmann, Matheus, et al.
(author)
-
Tailored PEO synthesis and in-situ ATR-FTIR study of PtSnO2/Nb coral-like structures for application in ethanol electrooxidation
- 2024
-
In: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 1002
-
Journal article (peer-reviewed)abstract
- Coupling the electrooxidation of organic compounds (EOO) with hydrogen evolution can be a sustainable way for green hydrogen production, and therefore it 's of great interest to the development of suitable electrocatalysts for efficient EOO. In this study, we present the successful solvothermal synthesis of a Pt-based electrocatalyst for an ethanol oxidation reaction (EOR), using a coral-like structure as substrate which was prepared by plasma electrolytic oxidation (PEO) on a metallic niobium. Chemical analysis revealed the predominance of SnO2 in the PEO structure, while Pt doping demonstrated selectivity on the surface of the electrocatalyst. Cyclic voltammograms indicate a high electrochemically active surface area (122.45 m2 gPt-1 ), with an onset potential of 0.27 V vs. SHE. In-situ spectroelectrochemical analysis confirm the efficient ethanol electrooxidation with remarkable selectivity in C-C bond cleavage. The prepared electrocatalyst stands out as a promising contribution to advances in green hydrogen production by coupling EOR with hydrogen evolution.
|
|
| 9. |
- Chen, Kaixuan, et al.
(author)
-
Optimisation of deformation properties in as-cast copper by microstructural engineering. Part II. Mechanical properties
- 2020
-
In: Journal of Alloys and Compounds. - : Elsevier Ltd. - 0925-8388 .- 1873-4669. ; 812
-
Journal article (peer-reviewed)abstract
- The microstructure evolution in the as-cast pure Cu and Cu-(1.0–3.0)Fe-0.5Co and Cu-1.5Fe-0.1Sn (wt. %) alloys was characterised in the previous work. Herein, the plastic deformation characteristics were examined by uniaxial tensile tests at room temperature. Along with the microstructure evolution, the yield strength increased with increasing Fe content and reached a peak value at 1.5 wt % Fe, but thereafter decreased with the further addition of Fe in the Cu–Fe–Co alloys. Nevertheless, the tensile strength and elongation synchronously improve with increasing Fe content. In particular, the Cu-1.5Fe-0.1Sn alloy achieved the optimal strength–ductility combination. In terms of the strengthening mechanism, the (Fe, Co)- or (Fe, Sn)-doped copper encouraged impediment, trapping, and storage of dislocations by the iron-rich nanoparticles and grain boundaries, which enhanced the strength and sustained the work hardening and elongation. The evolution of mechanical properties under an alloying effect was quantitatively described by the strengthening models. The results indicate that the optimum balance between strength and ductility was achieved by designing a microstructure containing fine grains, intragranular smaller spherical nanoparticles, and a minor solute element with higher misfit and higher growth restriction effect. The necessities for engineering a microstructure to achieve simultaneously strong and ductile bulk metals were discussed.
|
|
| 10. |
- Chen, Kaixuan, et al.
(author)
-
Slow strain rate tensile tests on notched specimens of as-cast pure Cu and Cu–Fe–Co alloys
- 2020
-
In: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 822
-
Journal article (peer-reviewed)abstract
- Microstructure evolution in the as-cast pure Cu, Cu-(1.0, 2.0, 3.0)Fe-0.5Co (wt. %) alloys were characterized in the former work. The aim of the present study is to investigate the slow strain rate tensile (SSRT) performance and fracture behavior of the Cu–Fe–Co alloys reinforced with fined grains (FG) and iron-rich nanoparticles (NP), referred as NPFG structure. The plastic deformation and fracture characteristics were examined by multiaxial SSRT tests at 75 and 125 °C on notched specimens. The addition of Fe and Co enhanced the ultimate tensile strength and yield strength almost by double to triple times the properties compare to pure Cu, along with an acceptable reduction in ductility, both at 75 and 125 °C. The SSRT properties of the copper samples varied as a function of temperature and alloying content. The analysis of fracture surface indicates the effect of iron-rich nanoparticles and grain boundaries on the deformation and fracture processes. The Kocks-Mecking model was applied to describe the SSRT experimental results with fitting parameters. The model predicted the dynamic recovery ability of the copper samples with different Fe, Co content and temperature. The evolution mechanism of SSRT properties upon alloying content and temperature was discussed in terms of the microstructure characterization, fractographic observation, deformation modeling, strengthening models as well as the analysis of strain-hardening curves. The results indicate through further microstructural engineering the NPFG Cu–Fe–Co alloy is promising in utilization as the canister for the storage of the nuclear waste.
|
|
