Ebtesam El Farhatey

The current research is concerned with the structure, morphology, and physical properties of a double perovskite La2FeCrO6. The crystallite size of the sample was determined to be 22.46 nm using the modified Scherrer equation. The elemental composition of La2FeCrO6 was confirmed through X-ray photoelectron-spectroscopy (XPS), which detected La, Fe, Cr, and oxygen, as well as oxygen deficiencies that significantly impact the observed ferroelectric behavior in the investigated sample. High-resolution transmission electron microscopy (HRTEM) verified the nanoscale preparation of the sample with an average particle size of 33.32 nm. Thermogravimetric analysis (TGA) was employed to investigate the thermal properties of the sample including the calculation of thermodynamic functions such as changes in enthalpy (ΔH) and entropy (ΔS) for La2FeCrO6. The material exhibits an optical direct transition with a band gap value of 3.4 eV and an Urbach energy of 2.5 eV. Due to its large specific surface area and band gap value, La2FeCrO6 shows promise in applications such as photocatalysis and water purification. The ac conductivity of La2FeCrO6 follows the universal dielectric response (UDR), and the P-E loop of the sample demonstrates its ferroelectric behavior.

A novel core/shell nanoferrite material has been developed for use in various potential applications. Rare-earth doped calcium-ferrite with the compositional formula $$\text{Ca}{\text{Fe}}_{1.925}{\text{Sm}}_{0.05}{\text{Gd}}_{0.025}{\text O}_4$$ was prepared as a core using the citrate auto-combustion method before being coated with PVA as a polymeric shell. High crystalline and single-phase orthorhombic nanoparticles are confirmed by XR-D (X-ray diffraction). An estimate has been made for the mean size of the crystal structures by analyzing the broadening of XR-D lines within a range of 20 nanometers. HR-TEM (high-resolution tunnelling electron microscope) micrographs also showed that the particles had an orthorhombic shape with well-defined boundaries. EDX (energy-dispersive X-ray) and FT-IR were used to investigate the elemental constitution and the molecular structure of samples. The dielectric properties were discussed in the basics of interfacial polarization and Koop`s model. The anti-ferromagnetic nature of the samples was identified by a VSM (vibrating sample magnetometer). The proposed composition was found to improve the electromagnetic absorption performance, which was confirmed with the measurements of optical parameters from the absorbance spectrum recorded by the UV–VIS–NIR spectroscope. The optical band-gap and Urbach energies of the synthesized samples have been investigated, in addition to the refractive index and the extinction coefficient. The Wemple-DiDomenico oscillator model was used to examine the dispersion energies.

Barium titanate materials are currently a special topic for scientific research due to their effective technological applications. The tetragonal BaTi1-xZrxO3 (0.0 ≤ x ≤ 0.3) nanoparticles (NPs) were synthesized using a modified citrate technique. The current work provides a comparative approach for the calculation of crystallite size, stress, strain, and elastic characteristics based on X-ray diffraction (XRD) patterns. Various models have been developed to analyze XRD data; these models differ in their assumptions, mathematical approaches, and the type of information they provide. The Scherrer model ignores lattice micro-structures that develop in nanostructures, such as intrinsic strain. To overcome such drawbacks, three Williamson-Hall models, (the uniform deformation model (UDM)), the uniform stress deformation model (USDM), and the uniform deformation energy density model (UDEDM) have been discussed. According to the USDM model, with increasing Zr ion concentrations, interplanar space increases, causing a drop in Young’s modulus. All the previous approaches take into account the diffraction angle (2θ)-dependent peak broadening, which is thought to represent a combination of size and strain-driven induced broadening.

Standard SiMo ductile cast iron automotive alloys are typically subjected to various hostile environmental conditions. For the current investigation, SiMo with a silicon content of 5% and molybdenum contents ranging from 0 to 1.5% was used. In two corrosive environments of 0.6 M NaCl and 0.5 M H2SO4, the study intends to present the corrosion behavior of high silicon molybdenum ductile cast iron (SiMo). Moreover, the impact of changing Mo on the microstructural characteristics has been investigated. The SEM-EDX examinations revealed that the nodule counts, M6C carbides, and lamellar pearlite increased while the ferritic matrix decreased with increasing Mo contents. It is clear that the addition of Mo reduces cast iron's rate of corrosion and thus increases its corrosion resistance. The results showed that SiMo cast iron alloy with 1.0 wt% Mo had a lower corrosion current (Icorr) in 0.6 M NaCl solution while lower corrosion current (Icorr) with the cast iron containing 1.5 wt% Mo in 0.5 M H2SO4 solution, which resulted in the lowest corrosion rate. The occurrence of a galvanic couple between the alloy matrix and the graphite nodules results in electrochemical corrosion, with the largest corrosion rates taking place at Mo-free alloy in both media.

In the current study, we developed a simple and biocompatible method for producing core–shell nanoparticles (NPs). Citrate auto combustion and green procedures were used to create core–shell Ag/CoGd0.025Er0.05Fe1.925O4 (Ag/CGEFO) sample with an average crystallite size of 26.84 nm. The prepared samples were characterized via different structural techniques, such as x-ray diffraction (XRD), Raman Spectroscopy (RS), High-Resolution Transmission Electron Microscopy, and Energy Dispersive x-ray analysis. These analyses were utilized to characterize and confirm the successful formation of the core–shell architecture. For core–shell NPs, all peaks of Ag and CGEFO ferrite are detected in the XRD, confirming the co-presence of the ferrite spinel phase and the cubic Ag phase. The magnetic hysteresis curves demonstrate typical hard ferri-magnetic behavior along with maximum magnetic saturation values up to 53.74 emu g−1 for the CGEFO sample, while an enhanced coercivity is detected for the coated sample. Moreover, the width of the hysteresis loop is increased for the Ag/CGEFO sample compared to the uncoated one. This indicates that the addition of Ag as a shell increases magneto crystalline anisotropy. Moreover, the E g of uncoated CGEFO is equal to 1.4 eV, increasing to 3.6 eV for coated ones. This implies the influence of CGEFO is diminished when the surface is coated with Ag (shell), and the reflectance of the Ag/CGEFO core–shell is nearly dependent on the reflectance of the Ag shell layer. Consequently, the Ag/CGEFO can be used as a light shielding substance.

High-silicon and molybdenum (SiMo) ductile iron is a common heat-resistant alloy that may be exposed to high-temperature wear during service in many of its applications. The wear behavior of four SiMo ductile iron alloys was evaluated at different temperatures up to 750 °C. This research focuses on the influence of various Mo contents on the microstructure, structural stability, and hence, the wear performance of such alloys. Thermodynamic calculations proposed the phase diagrams, critical transformation temperatures, and phase volume fractions in all samples by means of Thermo-Calc software. The dilatometry measurements were carried for confirming the theoretical results of Thermo-Calc thermodynamic calculations. The results revealed that the microstructure of SiMo ductile cast iron consists of nodular graphite and a ferrite matrix with carbides embedded in the fine precipitates at the grain boundary regions. The type of carbides and the nature of these fine precipitates are discussed according to EDX and SEM results. Adding molybdenum enhanced the wear performance of SiMo by decreasing the weight loss by about 40–70% compared to a Mo-free alloy. This is due to the increased molybdenum carbides, which increase hardness and improve wear resistance in SiMo alloys. The high temperatures have a negative effect on reducing the wear resistance at 250 °C. On the other hand, the wear resistance unexpectedly started to increase at higher temperatures of 500 °C and 750 °C because of the contribution of oxidative wear with abrasive wear by forming a protective oxide layer. Furthermore, the obtained results supported the idea that adding molybdenum improves wear resistance at high temperatures. Hence, SiMo has the potential to be wear-resistant material in wider applications requiring high-temperature wear resistance.

SiMo ductile irons, typical heat-resistant materials, are subjected to varied wear environments during operation in high-temperature applications. SiMo ductile iron castings of different thicknesses were cast in investment and greensand molds, achieving a wide range of cooling rates. The present work aims to investigate the effect of the cooling rate and alloying elements (Cr, V, and Ni) on the microstructure and the abrasive wear behavior of these grades of SiMo ductile iron at high-temperature 700 °C under different loads. Thermodynamic calculations were used to propose the phase diagrams, critical transformation temperatures, and phase volume fractions in all SiMo alloys by using the Thermo-Calc software then verified by and Differential Scanning Calorimetry (DSC). The microstructure of unalloyed SiMo ductile cast iron consists of graphite nodules and carbides embedded in the precipitates at the grain boundary regions in a ferrite matrix. The alloyed SiMo microstructure contains nodular graphite and the carbides promoted by the alloying elements (Cr and V). The alloyed SiMo alloys exhibit higher wear resistance than unalloyed ones. These wear results support that the microstructure plays a chief role in wear loss. The combination of M6C, VC, and M7C3 carbides embedded in a ferrite-pearlite matrix (alloyed SiMo) seems to be more resistant to wear than the ferritic matrix with lamellar pearlite and eutectic M6C carbides (unalloyed SiMo).

The present work scrutinizes a few uses of barium titanate BaTi1–xZrxO3 (0.0 ≤ x ≤ 0.3) nanoparticles, which are an innovative and highly promising material for a variety of applications, including optical applications; and waste water treatment. To estimate the quality of a synthesized powder relative to an already existing commercial powder, the samples were prepared using cheaper raw materials and simpler, faster procedures than those reported in other literature at lower annealing durations and temperatures. The prepared samples were characterized by field emission scanning electron microscopy (FESEM), and Raman spectroscopy, which confirmed the coarse nature of the samples and the system's tetragonality. Furthermore, UV–visible absorbance of all compositions was studied. It has been determined that optical transition is directly allowed after extensive research, and the optical band gap (Eg) values increase with increasing (Zr4+) ion concentration. The derivation of absorption spectrum fitting (DASF) technique was used to support the type of transition and calculate the value of the coefficient of electronic transition (n). Samples can perform overall water splitting and CO2 reduction processes. The Langmuir and Freundlich isotherms were used to comprehend the procedure of adsorption on the investigated samples. The BaTi0.8Zr0.2O3 has been used to successfully remove 99.9% of heavy metals (Cr6+) from wastewater. The obtained results provide new insights into the control of the structure, and optical behaviors in BaTi1–xZrxO3.

Zeolitic imidazolate framework-67 crystals (ZIF-67) anchored molybdenum disulfide nanosheets (MS) have been synthesized via a hydrothermal approach followed by a simple chemical method. The concentration of molybdenum disulfide was varied to investigate its impact on the electrochemical efficiency within the electrode nanocomposite. The shiny spot of this composite is the combination of two desirable properties, the conductive path created by MS, and the structural framework support provided by Zeolitic imidazolate framework-67 intercalated with nickel (Z67.Ni). The framework of Z67.Ni inhibits MS nanosheets from restacking over repeated charge and discharge cycles, which is why this specific nanocomposite was chosen. The superior synergistic impact of Z67.Ni crystals and MS nanosheets was established by the improved electrochemical behavior of Z67.Ni with 70 % weight percent of MS (Z67.Ni/MS7). This combination exhibited a specific capacitance of 308.5 F/ g at 1 A g−1 and a power density (Pd) of 2.78 kW kg−1 along with an exceptional energy density (Ed) of 83.98 W h kg−1. These impressive results highlight the high efficiency of this nanocomposite material for supercapacitor applications.

The main challenge of the current study is to produce nanocomposites (NCs) of (1-x) CoAl0.3Fe1.7O4 /(x)SmFeO3 with improved structural and magnetic properties using the citrate auto-combustion technique. High-resolution transmission electron microscopy images showed nanostructures with average particle sizes of 32.5 and 52.5 nm for SmFO3 and CoAl0.3Fe1.7O4, respectively. The anisotropy constant values for x = 0.3 are nearly 11 times greater than SmFeO3. The ratio of SmFeO3 incorporated into NCs adjusts their switching field distribution (SFD), making NCs with a low SFD recommended for recording applications. NCs offer the combined advantages of the two constituent phases and can be used to create new and more advanced applications. Based on the estimated data, the prepared NCs can operate at a frequency between 0.1 and 11.9 GHz, making them suitable for developing nanotechnology devices from radio waves traveling through the S-band to the Ku band.

An effective combustion technique is used to synthesize Sr0.8La0.2Fe12-xCuxO19 (x = 0,1) M-type strontium hexagonal ferrite nanoparticles (SHFNPs). The impact of La and La-Cu substitution on the structural, microstructural, and magnetic characteristics of SHFNPs is scrutinized. The samples are characterized using several experimental techniques, such as x-ray diffraction (XRD), Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and vibrating sample magnetometer (VSM). The obtained results reveal that the single lattice structure of the substituted strontium hexaferrite can be acquired by transforming Fe3+ to Fe2+ on the 2a site. Raman spectroscopy (RS) verifies the formation of all crystallographic sites of hexaferrite. The broadening of 4f2 and 12k peaks indicates the presence of disorder at the crystal sites resulting from the change in the chemical environment after doping with Cu2+ ions. FESEM images reveal flat hexagonal facets of the particle that signify the magneto-plumbite structure. The magnetic results provide high values of both intrinsic coercivity and (BH)max. The obtained data constitute good magnetic characteristics for perpetual magnet applications. Furthermore, the reduced coercivity of the Sr0.8La0.2Fe11CuO19 (SLCHF) sample with high magnetizations can be used to create microwave absorbing and data storage materials.

Ordered double perovskite La2FeCrO6 nanoparticles (NPs) were synthesized via the citrate auto-combustion technique. The prepared sample was characterized by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), and Raman spectroscopy, which confirmed the double perovskite structure of the studied sample. XRD illustrated that the investigated sample has an orthorhombic structure with an average crystallite size of 25.3 nm. La2FeCrO6 NPs exhibit a porous structure and spongy morphology, as determined through analyses using Brunauer–Emmett–Teller (BET) specific surface area and field emission scanning electron microscopy (FESEM). The studied sample exhibits anti-ferromagnetic (AFM) behavior with weak ferromagnetic (FM) components, as an example of d5(Fe3+)–d3(Cr3+) systems. The AFM behavior is caused by the super-exchange interaction between [Fe3+(d5)–O–Cr3+(d3)], according to the Kanamori–Goodenough (KG) rule. This behavior is induced by the pdπ hybridization between the eg orbital of the transition metal and the pσ orbital of the oxygen, while the one induced by the pdσ hybridization is FM. The number of excited-state configurations mediated by the pdπ hybridization in the Fe–Cr pair is greater than that mediated by pdσ hybridization. Pb(II) heavy metal ions are used in adsorption studies. The electrostatic nature of the bonding between Pb(II) and the La2FeCrO6 nano ferrite sample is thought to be the main cause of the observed high sorption of La2FeCrO6 to a Pb(II) ion. La2FeCrO6 has a favorable morphology, which bodes well for its prospective applications in Li-ion batteries, water purification, and gas sensors.