Crystallite Size Research Articles

Influence of ZnMn2O4/CuCo2O4 nano-fillers on the optical and electrical properties PVA/CMC/PEG blended polymers

(1-x)ZnMn2O4/xCuCo2O4 samples were synthesized by the co-precipitation method while polyvinyl alcohol/carboxymethyl cellulose/polyethylene glycol (PVA/CMC/PEG) blended polymer were fabricated by the casting method. Rietveld refinement analysis was used to determine the crystallite size and phase percentages for each composition were determined for all samples. The morphology and structure of PVA/CMC/PEG/(1-x)ZnMn2O4/xCuCo2O4 blends were examined using scanning electron microscopy and x-ray diffraction techniques. The reflectance and transmittance spectra were examined for blended polymers using a diffused reflectance spectrophotometer. Using LCR meter, the prepared blend films' dielectric properties were evaluated. When the blend is loaded with 0.9ZnMn2O4/0.1CuCo2O4, the lowest transmittance values (29–47 %) in the visible region are reached. As the CuCo2O4 doping levels became 10 % in the filler, the smallest direct and indirect energy gap values of 5.4 and (4.47, 1.9, 1.65) eV were attained, respectively. The linear and nonlinear optical parameters affected by the amount of CuCo2O4 in the filler samples. The optical conductivity of the doped blend reached its maximum value at x = 0.15. The CIE chromaticity diagrams revealed that the blends have varying degrees of blue color. The addition of (1-x)ZnMn2O4/xCuCo2O4 fillers improves the energy storage capability of the blends without raising the energy dissipation. The highest value of AC conductivity was achieved with the blend containing 0.9ZnMn2O4/0.1CuCo2O4. Nyquist plot revealed that the ionic conductivity increased as a result of doping. The obtained results suggest that the doped PVA/CMC/PEG/(1-x)ZnMn2O4/xCuCo2O4 blends might be used in a variety of industrial applications, including solar cell technology.

NiO/vermiculite composites prepared for photocatalytic degradation of methanol-water solution and hydrogen generation

A novel eco-friendly NiO/Vm clay based photocatalysts were synthesized from two vermiculites (Vm1 and Vm2) and nickel(II) nitrate hexahydrate (Ni(NO3)2·6H2O salt precursor by the chemical precipitation without and with the sodium hydroxide (NaOH) or ammonium hydroxide (NH4OH, 28% NH3 in H2O) as precipitation agents (Synthesis A) in comparison with the solid-state thermal decomposition (Synthesis B) at 600 °C. Structural properties of all specimens were characterized by X-ray fluorescence, scanning electron microscopy, X-ray diffraction, infrared (IR) and Raman spectroscopy. The photocatalytic performance of NiO/Vm composites was evaluated under UV radiation (λ = 254 nm) for decomposition of methanol-water to hydrogen over 4-h and the stable yield of hydrogen over the 24-h periods. The NaOH and NH4OH affected the NiO crystallite size and therefore the photocatalytic activity during 4 h. Different 2:1 layer charge of Vm1 (0.82 e−) and Vm2 (0.40 e−) and the specific surface area of Vm1 (about 43 m2/g) and Vm2 (about 34 m2/g) supported H2 yield of 628.2 μmol/gcat. and 596.8 μmol/gcat., close to 657.0 μmol/gcat. produced in the presence of commercial photocatalyst TiO2 Evonik P25. Crystalline NiO precipitated and anchored in NiO/Vm composites contained smaller crystallites than those in free NiO. Vermiculite silica surface supports coverage of NiO by hydrogen bonding to Si-OH groups influencing the geometry of the NiO crystal structure (disorder NiO(X)). The heterojunction with Si-O-Ni bonding, at which electrons transfer from Vm to NiO cause enriching electron density in NiO and favoring its photocatalytic activity. Photocatalytic hydrogen generation from methanol–water mixture at the presence of all specimens indicated the main product H2 and minimum by-products CH4 and CO. The stable hydrogen production for 24 h was confirmed only in the presence NiO/Vm1–24 while maintaining the NiO(X) in small crystallites. The thermal solid-state procedure provided the gradual dehydration of vermiculites and Ni(NO3)2·6H2O to the same amount and crystallinity of NiO in NiO/Vm1 and NiO/Vm2 composites. The results of this work confirm that vermiculites mixed layer structures with different negative layer charge play a dominant role as semiconductors for anchored NiO. The photocatalytic activity of NiO/vermiculite composites can be harnessed to treat wastewater containing organic contaminants.

“Yb modification of bismuth Ferrite: Unveiling Optical, Dielectric, and electrochemical properties for advanced applications”

This study explores the detailed impact of Yb3+ substitutional doping on the structural, optical, dielectric, and electrochemical characteristics of bismuth ferrite. Rigorous structural analysis conducted via X-ray diffraction confirmed the formation of a rhombohedral distorted perovskite structure, within the R3C space group. The investigation of crystallite size showed a reducing trend as Yb3+ content increased. Morphological studies revealed the presence of finely dispersed nanocrystalline grains, exhibiting particle size within the range from 281 to 197 nm. Raman spectroscopy unveiled notable phonon mode shifts towards higher wavenumbers, correlating with increased Yb3+ doping concentrations. Additionally, a discernible reduction in bandgap energy, from 2.15 to 1.98 eV, was observed with increasing doping levels. An improved dielectric response was observed with Yb3+ doping. Electrochemical assessments, employing cyclic voltammetry and galvanostatic charge–discharge techniques, revealed the superior electrochemical performance of the 30 % Yb-doped bismuth ferrite-modified electrode, demonstrating a specific capacitance of 575 Fg−1 at a scan rate of 10 mVs−1. These findings underscore the tailored engineering of Yb-doped bismuth ferrite nanoparticles, positioning them as promising candidates for the next generation of supercapacitor devices.

Beta radiation-induced thermoluminescence in pure and rare earth doped ZrO2 prepared by pechini-type sol-gel

Thermoluminescence properties of ZrO2, ZrO2:Gd3+, ZrO2:Gd3+–Dy3+, ZrO2:Gd3+–Yb3+, ZrO2:Gd3+–Er3+ and ZrO2:Gd3+–Sm3+ phosphors synthesized by Pechini method were investigated. XRD measurement suggested that all the samples are monoclinic and tetragonal multiphase. Crystallite size measured using SEM is around 200 nm–250 nm. The Tmax–TSTOP, variable dose and glow curve fitting methods were applied to the phosphors and reusability, dose responses and fading characteristics were examined. The phosphors exhibit a natural TL emission which disappeared after heat treatment. The glow curves of the pure ZrO2 have thirteen individual glow peaks, which include the peaks reported for the monoclinic and tetragonal phases. Although some peaks emerge at low irradiation doses, others can only be observed at high doses. Moreover, although the dopes blanched some of the peaks of pure ZrO2, they made others more intense. These peaks can be interpreted as if they emerged caused by the rare earth doping into the matrix material. On the other hand, Gd3+, Dy3+, Yb3+, Er3+ and Sm3+ dopes did not alter the peak temperatures of the matrix material. As a result, the individual peak intensities are very sensitive to the dopes. Fundamental trapping parameters of the trap levels were calculated, and the results are in good agreement with the given values of activation energies in the literature. Fading experiments show the materials have both normal and abnormal fading characteristics in long and short-term storage.

Investigation of the role of sintering temperature on microstructure, ac conductivity, and dielectric constant of single phase NiSnO3 nanopowder

This study investigates the effect of sintering temperature on the structural and electrical properties of co-precipitated nickel stannate (NiSnO3) nanopowder. Sintering temperatures, determined using Thermo Gravimetric Analysis (TGA), reveal a pure hexagonal perovskite structure through X-ray diffraction (XRD) analysis. Crystallite size increased from 10.56 nm to 26.04 nm and lattice strain decreased from 23.05×10−3 to 2.35×10−3 with higher sintering temperatures, analyzed via the Scherrer formula. d-spacing values from SAED patterns align with XRD results, and TEM analysis shows particle size growth from ∼11.43 nm to ∼28.16 nm as sintering temperature rises from 600°C to 900°C. Elemental composition has been confirmed through EDX, and elemental mapping analysis. Impedance spectroscopy via Cole-Cole plots indicated non-Debye-type or multiple relaxations with depressed semicircles due to grain and grain boundary effects. The sample sintered at 900°C exhibits the highest conductivity (8.35×10−5 Ω−1cm−1) with lowest activation energy of 0.31 eV and maximum dielectric constant values, with a minimum relaxation time of 0.00029 sec. Also the frequency variation of Z′′ and M′′ confirm the presence of non-Debye type relaxation. Scaling behavior of the imaginary part of complex impedance and conductivity spectra confirms temperature-independent conduction and relaxation mechanisms. These materials are used in energy storage applications.

Structural and optical properties of green-synthesised tricobalt tetroxide nanoparticles

In this study, we investigated the structural and optical properties of garlic extract-based green-synthesised tricobalt tetroxide nanoparticles. Transmission electron microscopy revealed a particle size range of 8–22 nm for the prepared powder sample. Powder x-ray diffraction data and Rietveld refinement results confirmed the spinel cubic crystal structure of the tricobalt tetroxide nanoparticles, with an average crystallite size of 11.23 nm. This crystal structure corresponds to the Fd3̅m space group and has an average lattice constant of 0.791 nm. The bond lengths of Co3+–O2− and Co2+–O2− are measured to be 0.188 nm and 0.190 nm, respectively. The FTIR data provided evidence of the presence of various functional bands, which helped qualitatively determine the purity of the sample. The UV–vis spectrum estimated two direct energy band gap values (3.7 eV and 2.2 eV) that may be useful for efficient interaction with a wide range of ray spectra to create more electron–hole pairs for various photo-responsive applications, such as dye degradation, solar cells, and optoelectronic components.

Green synthesized silver and zinc doped hydroxyapatite photocatalysts to remove methylene blue and Rhodamine B dyes from industrial wastewater

The present study focussed on the Scallop Sea shell waste utilized Hydroxyapatite and green synthesis of Canna indica leaf extracted Zinc (Zn) and Silver (Ag) doped Hydroxyapatite (HAp) formed by microwave irradiation method which is respectively represented as H, CIZH, and CIAH. The functional and structural characterizations (FTIR and XRD) of products confirm that the formed material was Hydroxyapatite due to the existence of characteristic absorption peaks and diffracted planes. The structural parameters such as average crystallite size, micro-strain (ε), dislocation density (δ), and particle size of the H, CIZH, and CIAH were calculated and the average Crystallite size are 42, 40, and 31nm. The morphology of the H, CIZH, and CIAH were assessed through FE-SEM and HR-TEM which could be majorly hexagonal-like (well distinct, and cluster of few rods). The EDAX spectrum and mapping confirmed the presence of chemical compositions of studied products. The anti-bacterial activities of studied products were assessed against Escherichia coli and Staphylococcus aureus, which exhibit good antibacterial activity. The photocatalytic activity of H, CIZH, and CIAH was examined against Methylene blue (MB) and Rhodamine B (RhB) dyes under UV light illumination. The degradation efficiency (%) of H, CIZH, and CIAH against MB and RhB dye were 58, 63, and 71%, and 58, 82 and 90%, respectively. A possible mechanism of the photocatalytic activity against the above-mentioned dyes is proposed. Thus, the present CIAH photocatalyst could be effective in degrading the wastewater.

Tailored solar collector coatings: Synthesis and characterization of CuFe2O4/PANI nanocomposites

This work successfully synthesized CuFe2O4 nanoparticles and CuFe2O4/PANI nanocomposites via a simple chemical precipitation method followed by in-situ polymerization. The main objective is to investigate the solar selective properties of these novel nanomaterials for solar collector applications. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy were used to characterize phase structure and crystallite sizes. Scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM), and UV–vis spectroscopy were performed to examine the morphology and optical characteristics of the nanostructures. XRD confirmed the development of spinel copper ferrite nanoparticles and copper ferrite/PANI nanocomposites with average crystallite sizes of 20.64 ± 4.04 nm, consistent with FT-IR and Raman results. Optical direct band gaps, estimated using Tauc plots, ranged from 2.7 eV to 3.3 eV for copper ferrite nanoparticles and reduced to 2.5 eV–3.0 eV with polyaniline inclusion. Reflectance spectra showed that CuFe₂O₄/PANI nanocomposites exhibited strong solar absorptance (αs) of 95 % in the visible spectrum and reduced emittance (εt) of 1 % in the infrared region, with a superior selectivity of 96.28 %. These nanocomposites can emerge as a novel class of selective coating materials with outstanding selective optical properties.

Comparative study of the structural, magnetic and electrical properties of cuprous delafossites CuBO2(B = Zn, Mn and Er) prepared using the flash auto-combustion technique

The flash auto-combustion method was utilized to produce Cu-based delafossites of CuBO2 (B = Zn, Mn, and Er). x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and x-ray photoelectron spectroscopy (XPS) were employed to verify the phase formation, surface morphology, and oxidation states of the synthesized delafossite samples. The crystallite sizes were determined to be 43, 16.76, and 21.66 nm for CuZnO2, CuMnO2, and CuErO2 nanoparticles (NPs), respectively. The magnetic characteristics of CuZnO2, CuMnO2, and CuErO2 samples were studied at room temperature, revealing their paramagnetic nature through the hysteresis effect. The Seebeck coefficient (S) for CuZnO2 was found to be positive, while it was negative for CuMnO2 and CuErO2. The thermoelectric power of CuZnO2 NPs was high, indicating their potential as materials for more efficient thermoelectric devices. Additionally, CuZnO2 exhibited an antimicrobial response against four-gram (+ve) bacteria, four-gram (-ve) bacteria, and the fungus Candida albicans (CA). The data obtained demonstrated that CuZnO2 NPs altered bacterial cell morphology, ultimately leading to bacterial cell death.

Synthesis of CoMnFe2O4 hollow microstructure decorated GO for photocatalytic degradation of organic dyes

Over the past decade, safeguarding marine life and aquatic ecosystems against deleterious dye pollutants has emerged as a paramount concern. Methylene blue dye stands out as one such pollutant capable of inflicting irreversible damage to marine ecosystems even at minute concentrations. Addressing this pressing issue, we synthesized a novel CoMnFe2O4/graphene oxide nanocomposite employing a microwave-ultrasonic method. This composite, comprising soft superparamagnetic CoMnFe2O4 hollow microstructures integrated onto graphene oxide surfaces, revealed a mesoporous structure with a notably high surface area, which was about 96.4654 m2.g−1. Various analytical techniques were employed to scrutinize the crystal structure, functional groups, surface chemical composition, and morphologies of the synthesized CoMnFe2O4/graphene oxide nanocomposite (X-ray diffraction, Fourier-Transform Infrared Spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy). The CoMnFe2O4 crystal phase appears to be cubic in the X-ray diffraction with a 28.91 nm Avg. crystallite size. The measured band gap energies for the CoMnFe2O4, graphene oxide, and CoMnFe2O4/graphene oxide nanocomposite are 2.23 eV, 2.90 eV, and 1.89 eV, respectively. Remarkably, under visible light irradiation, the nanocomposite exhibited an impressive degradation efficiency of 97.54 % within just fifty minutes (at pH = 7, Methylene blue conc. = 15 mg/L, and catalyst dose = 0.05 g.), attributed to a photo degradation rate constant (k value) reaching 0.07330 min−1. Notably, this efficiency nearly doubled with the introduction of H2O2 peroxide. The outstanding recyclability of the CoMnFe2O4/graphene oxide nanocomposite, sustaining optimal performance over four cycles without significant degradation, underscores its potential for long-term environmental remediation efforts. Moreover, its magnetic extractability from contaminated solutions enhances its suitability for advanced environmental applications.

Synthesis of Zn0.87(Fe, Al)0.065O – MO (MO = NiO, Fe2O3, CuO, and CoO) nanocomposites: Structural, vibrational, optical and antibacterial studies

One of the most effective strategies for achieving high-performance antibacterial activity is the synthesis of nanocomposites by combining different nanoparticles. Hence, Zn0.87(Fe, Al)0.065O – MO (NiO, Fe2O3, CuO and CoO) nanocomposites (NCs) with a 7:3 molar ratio were synthesized via the solution combustion method. The produced NCs structural, vibrational, and optical characteristics were investigated using XRD, FTIR, UV–Vis, and PL spectroscopies. The standard disc diffusion method was used to evaluate the antibacterial efficacy of the NCs. The lattice constant, crystallite size, bond length, dislocation density, and other relevant parameters of the NCs were also evaluated. XRD analysis revealed a well-defined mixed-phase structure for all 0.7Zn0.87(Fe, Al)0.065O – 0.3NiO (ZFA-Ni), 0.7Zn0.87(Fe, Al)0.065O – 0.3Fe2O3 (ZFA-Fe), 0.7Zn0.87(Fe, Al)0.065O – 0.3CuO (ZFA-Cu) and 0.7Zn0.87(Fe, Al)0.065O – 0.3CoO (ZFA-Co) NCs, indicating successful mixing of each metal oxide with the ZnO matrix. The average crystallite size within the NCs ranged from 14.21 to 18.10 nm, suggesting a degree of nanocrystallinity nature of all NCs. FTIR confirmed the presence of characteristic functional groups within the NCs. Moreover, all the synthesized NCs exhibited significant optical activation in the ultraviolet radiation range but visible light absorption was also observed when the composite formed with CuO and Fe2O3 nanoparticles. The band gap energy values exhibited variation between 2.72 eV for ZFA-Co NC and 2.90 eV for ZFA-Ni NC. Photoluminescence (PL) emission in the composite formation of ZnO NPs with other metal oxide were significantly influenced by the absorption range of the composite with pn-junction formation in a notable enhancement of antibacterial efficacy against bacterial strains of Escherichia coli and Staphylococcus aureus. Particularly, ZFA-Co NC exhibited an excellent antibacterial performance against both bacterial strains.

Rare-earth (Eu3+) substitution impact on the structural, morphological, magneto-dielectric, and electrochemical properties of Cd0.45Co0.55Fe2−y Eu y O4 spinel nanoferrites

A series of Cd0.45Co0.55Fe2−yEuyO4 (y = 0.0, 0.1, 0.2, 0.3) spinel nanoferrites (SNFs) were synthesized using a self-igniting process and employed as electrode materials for supercapacitor applications. The results demonstrated the formation of a single SNFs phase, as shown by the XRD data. The crystallite size lies between the range of 29.30–51.12 nm. The porosity percentage is within the range of 31.37%–32.99%. Rietveld refinement of XRD and Raman analysis revealed the pure spinel phase and no secondary phase was observed. The saturation magnetization and magnetic anisotropy were also decreased with the addition of Eu3+ in Cd–Co SNFs. The high coercive field was enhanced for Eu3+ doping as compared to pure Cd–Co SNFs. The dielectric constant was improved with the substitution of Eu3+ in Cd–Co SNFs. The dielectric tangent loss was reduced with the doping of Eu3+. The electrochemical performance of the Eu3+ doped Cd–Co SNFs achieved an impressive maximum specific capacitance at a lower scan rate. Based on these findings, the outstanding electrochemical performance of the Eu3+ doped Cd–Co SNFs suggests their potential as promising materials for high-frequency, magnetic ferrofluid, and supercapacitor electrodes.

Polymer-assisted synthesis of ternary magnetic graphene oxide nanocomposite for the adsorptive removal of Cr(VI) and Pb(II) ions

The presence of chromium [Cr(VI)] and lead [Pb(II)] ions in the water bodies have adverse effects on humans and aquatic life. Graphene oxide-based magnetic nanocomposites synthesized in the presence of chitosan (mGO/CS) or polyaniline (mGO/PA) as potential adsorbents for the removal of Cr(VI) and Pb(II) ions. The FTIR (Fourier transform infrared spectroscopy), EDX (Energy dispersive X-ray), XRD (X-ray diffraction) and SEM (Scanning electron microscopy) were employed to investigate the chemical composition, structural, elemental analysis, crystalline size and morphology of the nanocomposites. The FTIR results confirmed the synthesis of the nanocomposites by detecting peaks of specific functional groups. The average crystallite sizes of the mGO, mGO/CS, and mGO/PA nanocomposites were 17, 25, and 23 (nm), respectively, as determined by the Debye-Scherrer equation from the XRD data. Batch adsorption experiments were conducted for Pb(II) and Cr(VI) removal by varying the variables like pH, concentration of metal ions and contact time. The Box Behnken design (BBD) was used to optimize the adsorption parameters. Under the optimum conditions, mGO/CS and mGO/PA showed maximum removal percentages (%R) of 92.36 and 98.7 for Pb(II), and 85.25 and 93.08 for Cr(VI), respectively. The adsorption capacities were 110.84 and 118.44 mg/g for Pb(II), and 87.74 and 111.7 mg/g for Cr(VI) were obtained for mGO/CS and mGO/PA, respectively. The pseudo-second-order kinetic model and Langmuir isotherm fitted well to the experimental data and explain the adsorption mechanism of the nanocomposite materials for both metal ions.

Investigation on Heterostructured SeO2–TiO2 Nanofluoroprobe for Highly Selective and Sensitive Detection of a Neonicotinoid Insecticide, Imidacloprid in Soil and Water Matrixes

Heterostructured SeO2–TiO2 nanoparticles were used as a highly sensitive and selective fluoroprobe for the detection and determination of neonicotinoid insecticide imidacloprid. The sonication-assisted co-precipitation technique was used to create nanoparticles, which were then characterized using UV–Vis, SEM–EDS, HRTEM, XRD, and TGA. These analyses revealed that the nanoparticles had globular morphology, a crystallite size of 14 nm, a bandgap of 2.45 eV, and stability at high temperatures. Fluorescence emission at 548 nm wavelength exhibits high sensitivity and selectivity for imidacloprid over other pesticides with complete fluorescent quenching at 2 × 10–4 M concentration of imidacloprid. Stern–Volmer equation and thermodynamic parameters applied to the experimental data over a temperature range of 20–50 °C provide the Ksv value in the range of 1.56 × 105 to 2.69 × 105 M−1 and indicate strong interactions, dynamic, spontaneous, and endothermic quenching process. Furthermore, the excellent salient features and notably the unaffected performance even in the presence of various anions, fertilizer, and binary mixture of pesticides often sprayed on plants, will pave the way for the development of rapid, affordable, selective fluoroprobe for onsite monitoring of imidacloprid. The reliability for determination is also examined for spiked soil samples to develop a hybrid SeO2–TiO2 nanoparticles fluoroprobe as a simple alternative to existing techniques for the detection of imidacloprid.Graphical

Effect of calcination temperature on structural, optical, and morphological properties of RAlO3 (R = La, Sm) perovskite oxides

RAlO3 (R = La, Sm) have attracted the research community due to their interesting optoelectronic properties and viable applications. The solution combustion method allows for a faster process and lower calcination temperature than the traditional solid-state method and is an economical alternative to wet chemical synthesis for producing RAlO3. This work explores the thermal, structural, morphological, optical, and electrical properties of RAlO3 (R = La, Sm) synthesised by the solution combustion method using urea as fuel. Thermogravimetric analysis—differential thermal analysis (TGA-DTA) showed the crystallization temperatures of lanthanum aluminate (LaAlO3) and samarium aluminate (SmAlO3) at 864 and 887 °C, respectively. The x-ray diffraction (XRD) and Rietveld analysis revealed the structure of LaAlO3 as rhombohedral (R-3c) and SmAlO3 as orthorhombic (Pbnm). The LaAlO3 and SmAlO3 samples calcinated at 800 °C showed crystallite size (D) of 19.26 nm and 19.06 nm, respectively. The field emission scanning electron microscopy (FE-SEM) images show a highly porous and large sheet-like morphology with voids and cracks. High resolution transmission electron microscopy (HR-TEM) images and the selective area electron diffraction (SAED) pattern show crystalline nature and the indexed planes agreed with the XRD results. The LaAlO3 and SmAlO3 samples had specific surface areas of 16.374 and 12.953 m2 g−1, respectively. The TGA-DTA results were affirmed by Fourier transform infrared spectroscopy (FT-IR) results which showed only the presence of metal-oxide bonds for materials annealed at and above 800 °C. These results were further validated by the electron dispersive x-ray spectroscopy (EDX) and the x-ray photoelectron spectroscopy (XPS) showing no additional peaks. The band gap of 5.08 and 4.82 eV were calculated from ultraviolet-visible spectroscopy (UV–vis) for LaAlO3 and SmAlO3, respectively. The results imply that the solution combustion technique using urea as fuel is a viable route for synthesising RAlO3.

Microstructural evolution of CrCuFeNiZn nanocrystalline high entropy alloy prepared by mechanical alloying

High Entropy Alloys (HEAs) have become the most researched structural materials in the scientific community during the last decade due to their attributes like excellent strength and wear resistance. In this research, CrCuFeNiZn HEA was prepared using mechanical alloying technique. Further, X-ray diffraction (XRD) and Scanning electron microscope (SEM) analysis of prepared HEA were carried out at various milling time intervals (10 min, 5 h, 10 h, 15 h, 20 h, and 25 h) to determine solid solution formation. Results manifest that CrCuFeNiZn HEA exhibited BCC + FCC (dual phase) structure after 25 h of milling. Moreover, the crystallite size as measured from the XRD analysis for the 25 h milled powder was found to be 32.8 nm and lattice strain at the end of milling is calculated to be 0.428%. SEM-EDS analysis further confirms the homogeneous distribution of the constituting elements in the as-fabricated alloy aggregate.

Revision of JIS R7651: “Measurement of lattice constants and crystallite sizes of carbon materials”

Revision of JIS R7651: “Measurement of lattice constants and crystallite sizes of carbon materials”

Impact of cerium and tungsten doping on the structural and optical characteristics of NiO nanoparticles

Co-precipitation, a rapid and effective technique, was used to produce Ce- and W-doped NiO nanoparticles at pH values of 10 and 12. The FT-IR, UV-visible spectroscopy, and X-ray diffraction techniques were used to examine the structural and optical characteristics. The NiO nanoparticles’ distinct XRD pattern revealed their monoclinic shape and crystalline origin. According to the Debye-Scherrer formula, the crystallite size of NiO nanoparticles decreased to 5.94 nm and 7.12 nm, respectively, when 5% Ce and 5% W were added, from 20.41 nm for undoped. Using UV-VIS absorption spectra, the optical band gap and the wavelength of maximum absorption were found. It was found that both of these parameters were influenced by the pH level and the concentration of Ce and W metal dopants. It can be concluded that doping has a higher impact on Cerium compared to Tungsten and at pH 10 compared to pH 12. This work presents a comprehensive investigation of the effects of pH and dopant concentration on the properties of Ce and W-doped NiO nanoparticles.

Correlation between Crystallite Characteristics and the Properties of Copper Thin Film Deposited by Magnetron Sputtering: Bias Voltage Effect

This work investigates the properties of copper thin films deposited by magnetron sputtering. The substrate is biased by a negative voltage (Vs), which controls the energy ions bombardment during the deposition of the thin films. In order to focus solely on the ions energy contribution, the power supply was fixed and the working pressure was selected at 5 Pa. This ensures energetic sputtered particles completely thermalized, by a sufficient number of collisions with the Argon gas. X-ray diffraction analysis revealed that substrate voltage Vs affects essentially the structure and size of the formed crystallites. The preferred orientation (111) and the larger crystallite size (30 nm) were achieved at Vs = - 60 V. The Cu (111)/(200) peak intensity ratio is maximal (12.55) at - 60 V, corresponding to the lowest resistivity value (6.33 mW.cm). Optimum corrosion resistance of the deposited thin film was achieved at -60 V. At high crystallite sizes, nanoindentation analysis showed a thin film that is more elastic (133 GPa) and less hard (1.96 GPa).

A study on the facile synthesis of Cu-influenced organic framework and their characteristic properties

Today's nanomaterial scientific phases have been evolving through the most considerable novel MOF nano-characters. This study has described that the Cu (Copper) Nano-Metals based Metal-Organic Framework was synthesized by an affordable solvothermal method. With the facilitates of characterization methods, their factual physiochemical properties including Cu-MOF's crystalline characters, vibrational, surface morphology, surface chemical states, and obtained surface area have been examined. The X-ray diffraction–structural examination described the evident formation of metal oxide-coordinated MOF crystalline material. Before calcination, the MOF nanomaterial possessed an actual crystalline character of Cu-MOF with 22.3 nm of crystallite size then it became recrystallized after calcination. The co-contributions of Oxygen-linked organic molecular vibrational signatures upon Cu-O were analyzed through the Fourier Transform Infra-Red spectroscopy. Surface morphological magnifications exhibit plenty of pentagonal-shaped Cu-MOF nanomaterial with uniform distribution. Such a case also exhibits a flower-shaped Cu-MOF between pentagonal shapes with considerable surface porosity. X-ray photoelectron spectroscopy (XPS) has exhibited that the presence of oxygenated molecules contained copper oxide B.E states of synthesized Cu-MOF material. The UV–visible spectroscopy analysis has taken and the estimated bandgap of the Cu-MOF material is 2.3 eV. The thermal stability of the material has been analyzed through Thermo-Gravimetric analysis. To determine the internal structure of the Cu-MOF, an HR-TEM investigation was carried out. BET analysis exhibited 65.152 m2/g of active surface area. Due to the novel particle morphology with beneficial surface characteristics, the Cu-MOF possessed an efficient charge storage capacity of 383.3 Fg-1 due to its novel property.