Papers by Keyword: X-Ray Diffraction (XRD)

Abstract: In this paper, various annealing conditions using Al-based (Ti/Al/Ti/Au=70nm/100nm /5nm/120nm) and Ni-based (Ti/Ni/Ti/Au=20nm/90nm/5nm/120nm) metal contacts to n-type and p-type ion-implanted 4H-SiC epi layers have been studied in the effort to optimize simultaneous ohmic contact formation with the lowest specific contact resistance (SCR) values. Values of 1.091×10^-4 Ω∙cm² and 1.158×10^-5 Ω∙cm² were achieved using Al-based Ohmic metal contacts for p-type and n-type 4H-SiC, respectively, at an annealing temperature of 950°C and under vacuum for 90 sec. Ohmic formation mechanisms were analyzed using the X-Ray Diffraction (XRD) surface analysis method, indicating Ti₃SiC₂ alloys to be the key intermediate layer formed at SiC/Ti interface, responsible for Ohmic properties to p-type SiC. The paper summarizes the metal process combinations possible for the formation of Ohmic contacts to both n-type and p-type 4H-SiC, offering various options in either using the same metal materials and/or common annealing conditions.

Abstract: Barium halide activated with Eu is a typical phosphor material used in imaging plates for computed radiography applications. In this study, BaBrX: Eu (X = Cl, I) was synthesized via the hydrothermal technique. The aim of this study is to further explore the feasibility of the hydrothermal method for synthesizing phosphor materials. This was determined by studying the effect of Eu addition on the structural and optical properties of BaBrX (X = Cl, I). X-ray diffraction (XRD) was employed to determine the crystallinity of the prepared samples, while optical properties were observed using photoluminescence (PL) spectroscopy. The sharp, narrow, and high-intensity peaks of XRD diffractogram indicated that all samples exhibited good crystallinity. The addition of the Eu element as an activator resulted in a blue-shift with broad and higher intensity of the main emission peak for several samples. This study demonstrates that the addition of the Eu element to the host materials has altered the structural properties and improved the optical properties of the prepared samples, significantly demonstrating the feasibility of the hydrothermal method for synthesizing phosphor materials.

Abstract: X-ray Absorption Spectroscopy (XAS) experiments are usually performed at synchrotron facilities utilizing high-intensity X-ray sources produced by particle accelerators. However, this study showcases an in-house XAS experiment carried out using an X-ray Diffractometer (XRD) system that is typically available in material laboratories. The Rigaku SmartLab XRD was employed and configured for the Bragg-Brentano (BB) measurement mode. 20 keV electron energy is used to energize a molybdenum (Mo) target and produce high-intensity white X-rays via the Bremsstrahlung effect. Several crystals were tested as crystal analyzers for white X-ray dispersion to obtain optimal X-ray intensity and resolution. The detector energy filter is optimized to increase the peak-to-background ratio then the energy dispersion and resolution over the θ/2θ scanning range is determined and evaluated. The performance of the in-house XAS experiment is compared to theoretical calculations and synchrotron data from previous studies by observing resolution and spectrum shape and peak features of deposited Copper (Cu) and Copper Oxide (CuO) samples. Our findings showed that the absorption edges were clearly observed despite the peak broadening and shifting above absorption edge. Furthermore, some peaks were also observed in the XAS spectrum which originated from X-ray fluorescence of elements from both the samples and hardware components.

Abstract: Due to the combination of its numerous excellent mechanical qualities, the flexible iron has been used more and more since its invention in 1948. To develop significantly improved characteristics, the unnecessary investigation is being done. The most recent development in the field of flexible iron, or SG iron, is Austempererd malleable iron. At four different temperatures, two different types of spheroidal graphite (SG) cast iron samples with varying copper weight levels were austempered. The temperatures used for austempering were 200°C, 300°C, 350°C, and 400°C. As a component of the austempering time and temperature, the effect of the austempering process (i.e. time and temperature) on the mechanical characteristics of spheroidal graphite iron was investigated. The progress of spheroidal graphite iron's properties was significantly influenced by the pace of cooling and the extinguishing process. The organisation of different stages during isothermal change under varied austempering settings has also been the focus of XRD analysis. By using SEM, graphite morphology has been focused on. For this investigation, samples were obtained from the castings' focal point for XRD analysis. It was discovered that virtually always, it is possible to discriminate between the ferrite (110) and austenite (111) lines. The ferrite (110) line is growing with expanding austempering time and declining with increasing austempering temperature, whereas the highest power of the austenite (111) line is expanding with expanding temperature. Thus, very precise control of the interaction components (austempering duration and temperature) is required for austempering. The results showed that, when compared to other grades (N1) through the various austempering processes used in this evaluation, ADI containing the alloying component copper (grade N2) achieved crucial mechanical qualities.

Abstract: Main initiative of this study is to report the changes occurred in the particle size and distribution of nano-hydroxyapatite powders due to the novel effect of Plant Leaf Mediated Natural Extracts (PLMNEs). Wet-Chemical precipitation method is used to obtain homogeneous nano-hydroxyapatite powders. These nano-hydroxyapatite powders have been synthesized by using different precursors and relative concentrations. The natural extracts used as Natural Stabilizers (NSs) are derived from Soya Leaves (SL) and Spinach Leaves (SpL) for the preparation of nano-hydroxyapatite. Present study reports the morphological changes in nano-hydroxyapatite and has been characterized using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Small Angle X-Ray Scattering (SAXS). Till now no studies have been reported on synthesis of nano-hydroxyapatite using Plant Leaf Mediated Natural Extracts as precursors. The Natural Stabilizers used have been found to show evidence of several medicinal effects.

Abstract: In this study, the 2024 Al powder with different weight fractions of graphite is mechanically milled using a high-energy ball mill for 3 hours each in the nitrogen environment. The milled powder is compacted at an elevated temperature. X-ray diffraction is used to phase analysis of milled powder as well as compacted specimens. Optical microscopy is used for microstructural analysis and hardness measurements are done for the evaluation of mechanical properties. The hot compacted specimens are also tested for their wear properties. Results show that there is no new phase formed during mechanical milling. But, after hot compaction of the milled powder, Al₂Cu formed due to precipitation. No reaction is observed between the aluminum and the carbon (graphite) after milling as well as hot compaction. Microstructures of all hot compacted specimens are not showing pores, which, signifies full density after compaction. The formation of Al₄C₃ is not observed at any stage of processing. Therefore, graphite is uniformly distributed in all specimens, and the same is observed at grain boundaries of α-Al grains in the microstructures. Hardness increases with the addition of 1 wt.% graphite but it decreases with a further increase in graphite. The wear resistance of 2024 Al with 1 wt% graphite is the highest among all the compositions. The high hardness and wear resistance of 2024Al with 1 wt% graphite is the consequence of precipitation of Al₂Cu during hot compaction and the presence of graphite which creates hindrances in the metal matrix. The presence of free graphite in the vicinity of grain boundaries acts as a solid lubricant which improves wear resistance of 2024 Al.

Abstract: Epoxy was loaded with varying concentrations of fly ash and was characterized for its structural properties using XRD and SEM. The XRD results revealed reduction of crystallinity with increase in filler content indicating that the composites are semi crystalline in nature. The SEM images showed that at lower concentration of filler content, fly ash is uniformly distributed within the epoxy and at higher concentrations of fly ash, agglomerates were observed. Mechanical properties such as tensile and compressive properties were estimated and the results showed that, the composites exhibit enhanced tensile strength and compressive strength for epoxy with 20 wt% fly ash. Flammable properties such as heat release rate, peak heat release rate, time to ignition, CO and CO₂ yields are estimated and reported. Decrease in combustion time, peak heat release rate, time to ignition, CO and CO₂ yields with increase in filler content clearly indicates the superior flammability performance of epoxy composites loaded with fly ash.

Abstract: Nickel Oxide nanofibers were successfully prepared by electrospinning with a precursor mixture of Ni acetate/polyvinylpyrrolidone (PVP), followed by calcination treatment of the electrospun composite nanofibers. The parameter of solution and effect of applied voltage to the morphology of nanofibers were studied. Both Ni acetate/PVP and NiO NFs, nanofibers were characterized by FESEM and XRD. The results found that the nanofibers form with smooth surface without beads and the calcination temperature was at 500°C to produce NiO nanofibers.

Abstract: Solid oxide fuel cell has become one of the interest in the sustainable energy field. In order to improve the efficiency of a solid oxide fuel cell (SOFC), the interconnect must be coated with a protective coating of (MnCO)₃O₄ spinel coated stainless steel. Commercial manganese cobalt (MnCO)₃O₄ was used as a protective coating on ferritic stainless steel in this study using the electrophoretic deposition (EPD) coating technique. This article examines the impact of voltage deposition towards morphological characteristics. The goals of these studies are to find the best interconnect coating parameter while experimenting with voltage deposition. The spinel coated interconnect (MnCO)₃O₄ was studied using Elemental Energy Dispersive X-ray Spectroscopy (EDS). The surface morphology and coating thickness are examined using a Scanning Electron Microscope (SEM). X-ray diffraction (XRD) is used to determine the phase of the spinel coated interconnect. The EPD coating technique for (MnCO)₃O₄ spinel coated interconnect is carried out in an aqueous suspension with 30V and 40V with coating durations of 20s, 30s, 40s, 50s, and 60s. By observing the deposition morphology and thickness coating at 30V and 40V, the best covering parameter for interconnect is 30V, 40s which fulfil the interconnect requirement.

Abstract: Flue Gas Desulfurization (FGD) is a waste incineration process commonly used to eliminate sulfur dioxide (SO₂) from flue gas power plants. FGD by-product recorded a rich gypsum content, also known as calcium sulfate dehydrate (CaSO₄•2H₂O), which has promising practical applications in plaster mould production. Plaster of Paris (POP) with a chemical composition of calcium sulfate hemihydrate (CaSO₄•0.5H₂O) is widely used in plaster mould production because of its quick setting and hardening upon moistened. Naturally, gypsum with 2 molecules of crystalline water can change to 1.5 molecules via the dehydration process. Various dehydration methods were conducted to transform FGD gypsum to hemihydrate. After undergoing different autoclave processes, the phase transition of FGD by-products was identified by X-ray diffraction (XRD) mode and compared with commercial POP. Chemical composition of FGD sludge contains a high amount of calcium oxide (CaO), sulfur trioxide (SO₃) and boron trioxide (B₂O₃), as well as other impurities such as fluorine (F), chlorine (Cl), and magnesium oxide (MgO). Based on phase analysis, sample H1 to H5 show the percentage of hemihdyrate is 1.5%, 19.7%, 2.8%, 1.2%, and 46.1%, respectively, after different dehydration methods.