Material Grain Research Articles

SnO2: Investigation of optical, structural, and electrical properties of transparent conductive oxide thin films prepared by nebulized spray pyrolysis for photovoltaic applications

• Tin based conducting oxide material is prepared using the starting material Tin (II)Chloride. • The molar ratio of the material varies from 0.1 M to 0.5 M by dissolving in isoproponal and a few drops of Hydrochloric Acid (HCl) for fine dissolution. • The material crystallinity and grain size has been improved while the prepared SnO 2 substrates were annealed. • The morphological study reveals that the grain size and stoichiometric of the prepared material increases when the molar concentration increases with annealing temperature. EDX studies authenticate the presence of required elements (Sn = 85.75 % & O = 11.31 %) and after annealing it shows the elimination of unwanted elements. The optical band gap values are increased from 3.71 eV to 3.75 eV for with and without samples due to quantum confinement effect. Hall Effect studies shows that after annealing the resistivity will be decreased in the order of 10 -3 Ω cm. • FTIR analysis was used to compare the bending and stretching vibrations of the functional groups associated with the O-sn-O bond for both annealed and non-annealed samples. In the present investigation, we are focused on the preparation of Tin based conducting oxide material. The starting material used is Tin (II)Chloride. The molar ratio of the material varies from 0.1 M to 0.5 M by dissolving in isoproponal and a few drops of Hydrochloric Acid (HCl) for fine dissolution. The well-clean Micro slides were coated using the Nebulizer Spray Pyrolysis (NSP) process at a deposition temperature of 350 °C ± 10 °C and annealed at 300 °C for three hours. The structural, optical, electrical, thickness, functional, and morphological studies are validated with and without annealing. The material crystallinity and grain size has been improved while the prepared SnO 2 substrates were annealed. The morphological study reveals that the grain size and stoichiometric of the prepared material increases when the molar concentration increases with annealing temperature. EDX studies authenticate the presence of required elements (Sn = 85.75 %& O = 11.31 %) and after annealing it shows the elimination of unwanted elements. FTIR analysis was used to compare the bending and stretching vibrations of the functional groups associated with the O-sn-O bond for both annealed and non-annealed samples. The optical band gap values are increased from 3.71 eV to 3.75 eV for with and without samples due to quantum confinement effect. Hall Effect studies shows that after annealing the resistivity will be decreased in the order of 10 -3 Ω cm.

Intrinsically Conducting Polymer Binders for Battery Electrodes

Binder materials are needed to keep particles of active masses in electrodes for batteries and supercapacitors together and to ensure their adherence to the current collector. Mostly synthetic polymeric materials are used. Because they are electrochemically inert, they do not add to the storage capacity of the electrode. Intrinsically conducting polymers ICPs such as polyaniline, polythiophene or polypyrrole can provide these functions also. They show electronic conduction because of mobile charge carriers generated in them by oxidation or reduction. In addition to providing the binder-function, they improve electronic conductance of the electrode mass because of their inherent conductivity and can also contribute to the charge storage capability of the electrode in the range of potential of the redox activity of ICPs in the used electrolyte solution. In most reports on the application of ICPs as component of conductive binders, their incorporation results in enhanced specific capacity and notable improvement of C-rate capability of electrodes. In addition, ICP binders provide partial or complete wrapping of grains of active electrode materials, which effectively inhibits the interaction with the electrolyte, suppressing side reactions and degradation of functional properties.

Illitization in the Mt. Simon Sandstone, Illinois Basin, USA: Implications for carbon dioxide storage

Clay mineral cementation is one of the most important controls on sandstone reservoir properties. In this paper, the diagenetic history of the Mt. Simon reservoir complex is studied to reveal the origin, timing, and controls of illitization. Samples of sandstone and shale from Mt. Simon reservoir complex were acquired from the Illinois Basin–Decatur Project (IBDP), a CO2 storage demonstration project in the central Illinois Basin. Petrographic, SEM, TEM, XRD analyses and K/Ar age dating were completed to identify the major detrital and diagenetic components of the samples and reveal illite to be the major clay component in all samples. Illitic clay coatings in the lower Mt. Simon reservoir are identified as a major control on reservoir properties by inhibiting major precipitation of authigenic quartz during illitization, resulting in highly permeable sandstone, essential for CO2 storage. The coating box-work morphology and mineralogy are indicative of a detrital smectite origin with subsequent illite growth associated with feldspar dissolution and kaolinite alteration. The mineralogy of bulk material and separate grain size fractions (2–0.6 μm; 0.6–0.2 μm; < 0.2 μm) with illite polytypes 2M1, 1M, and 1Md were quantified and age dated via 40K-40Ar methods. The shales or reservoir seals contain the highest proportions of detrital illite with illite in the lower Mt. Simon Sandstone reservoir identified as solely diagenetic. Two major events of illitization are identified throughout the Mt. Simon with more porous reservoir rock exhibiting the older event from approximately 360 to 315 Ma and tighter sandstone units with reservoir properties too low to be considered reservoir exhibiting illite dates from 250 to 220 Ma. This partitioning of illitization is attributed to varied mineralogy controlled by depositional changes and evolution of the greater basin.

Nd3+ added Mg– Cd ferrite material study the thick film gas sensing properties

The general formula Mg1-x Cd x Fe2O4 (x = 0.0,0.1,0.3, 0.5, 0.7) was used to prepare 5 wt % Nd3+ nano crystallite ferrite samples using the oxalate co-precipitation method. XRD, SEM, and FT-IR were used to characterize the samples. The cubic spinel structure was confirmed by XRD, which revealed an orthoferrite (NdFeO3) secondary phase. In the range of 350–800 cm−1, Mg–Cd ferrites show two distinct bands of absorption. In Mg–Cd ferrites, the surface morphology SEM study shows that grain size increases with Cd2+ concentration and decreases with Nd3+ presence. The response of Mg–Cd ferrites with Nd3+ is higher than that of Mg–Cd ferrites without Nd3+. With an increase in Cd2+ concentration, the response and recovery times of Nd3+ added Mg–Cd ferrites are speed up. Cd ferrite sensors combined with Nd3+ have faster response and recovery times than other samples. These differences are dependent on the test gas's composition as well as the material's grain size.

Principles of porous reacting electrodes modeling (a review)

The production volume of rechargeable batteries and requirements for them, in particular with respect to increasing voltage, specific capacity, charge-discharge currents and reliability, are growing and will grow more rapidly. Today it is clear that the limiting factor of their development is insufficient understanding of processes which taking place there. The review discusses basic equations that describe ion and electron transfers and electrochemical reactions which lead to an uneven distribution of processes in the system. The possibility of obtaining analytical and numerical solutions is analyzed for the stationary case and for the case when characteristics of the local electrode area depend on the state of charge. A large number of works are based on the Doyle-Fuller-Newman model, which considers both the distribution of the process in the electrode and the diffusion into the solid phase of the active component which formed as a result of an electrochemical reaction on the crystals surface. It is noted that such models adequately describe the processes only when empirical or semi-empirical dependences on the state of charge for local current density, equilibrium potential or transfer coefficients are used. Papers based on quantum-chemical calculations of potentials, estimating entropy factors, as well as the decomposition of solid solutions are discussed. A modern classification of approaches applied in battery modeling with the aim of using them in electronic battery management systems is presented. It is concluded that there is insufficient understanding of the processes occurring at the level of active material grains during phase transformations.

Noninvasive tracking of solidification using ultrasound

Noninvasive tracking of solidification is typically done by monitoring the sample’s surface temperature. This approach is error-prone and not always appropriate for complex geometries and often does not provide complete information on the sample’s transitioning phases. This feasibility study investigates using ultrasonic waves to noninvasively track solidification in wax. Ultrasonic sensors are used in through-transmission mode to monitor the response over the solidification period. The difference in speed of sound between the wax’s liquid and solid phase allows for the solid fraction of the sample to be calculated over the solidification period and the time of complete solidification to be identified. Changes in attenuation during solidification are consistent across experiments. These changes are likely to provide additional information about the cast once they are fully understood. Temperature probes are used to verify the results obtained from the ultrasonic data. The ultimate goal of the project is to use a metal sample and connect information from the ultrasonic signal to the material properties and grain structure of the cast using noninvasive ultrasound technology.

Phase field microelasticity accommodating large deformation and modeling of voids evolution under creep

The phase-field microelasticity theory of Khachaturyan has been widely applied in materials science that is based on the small strain assumption. Here we develop an incremental realization of inelastic deformation (IRID) algorithm to deal with finite/large deformation with yet small elastic strain. A large deformation process is decomposed into a sequence of small deformation processes with intervals. At each interval the grids are stretched to accommodate the average inelastic deformation and advection/rotation operations are performed to account for the heterogeneous inelastic deformation. It is shown that Kachaturyan’s Fourier-transform based solutions can be adapted to the stretched grids. The IRID algorithm is compared against literature results regarding growth of a single void under remote stress of different triaxialities. Based on the IRID algorithm a phase-field model is developed that incorporates material microstructure, plasticity, multicomponent diffusion, and surface and grain boundary diffusion. The void growth kinetics and morphology evolution under coupling of diffusion and plasticity under creep are studied and the results show that coupling of the two mechanisms can significantly accelerate growth and coalescence of multiple voids at grain boundaries.

Estimating Multidomain Wall Motion in Polycrystalline Materials

This article presents an approach to estimate multidomain wall motion obtained on video from a grain of polycrystalline material. The first step consists of pre-processing the image to reduce noisy artifacts. Then, an object detection technique is applied to the pre-processed images to locate the position on the domain wall. The location data collected from each image are used to display the estimated movement of domain walls from all input video frames. The experimental results allow the improvement of models based on the behavior of the individual movement of each wall.

Softening behavior of stationary shoulder friction stir welded joint for thick-plate Al–Li–Cu alloy

12-mm-thick Al–Li–Cu alloy plates were fabricated by stationary shoulder friction stir welding (SSFSW) to evaluate the softening behavior of the whole joint under a given rotational speed of 400 rpm and a welding speed of 60 mm/min. Continuous dynamic recrystallization, discontinuous dynamic recrystallization, and geometric dynamic recrystallization are the main dynamic recrystallization mechanisms in SSFSWed joints. Such mechanisms help to gradually change rolling grains of base material (BM) into equiaxed grains of welding nugget zone (WNZ) and significantly lower dislocation density. The decrease in dislocation density is the main reason for joint softening. Continuous coarsening of T1/θ′ in heat affected zone (HAZ) and thermo-mechanically affected zone (TMAZ) weakens the strengthening effect. The development of precipitate-free zones and re-precipitation of TB primarily contribute to severe softening at the interface between HAZ and TMAZ on the advancing side (AS-HAZ-TMAZ). The serious softening behavior at the bottom of WNZ is attributed to the re-precipitation of TB and the complete dissolution of T1/θ′. Hardness profiles and tensile strength distribution of SSFSWed joint exhibit a “W” pattern, while a “U” pattern appears at the bottom. The hardness profile and tensile strength of WNZ are significantly poorer at 8–12 mm from the weld surface compared to those at 0–8 mm. Softening behavior also results from the higher fractions of the maximum Schmid factor (in 0.4–0.5) and Cube. From BM to WNZ, fracture mode transitions from quasi-cleavage fracture to plastic fracture.

Study of Optical Rectification in Polycrystalline Materials Based on Random Quasi-Phase Matching

Random quasi-phase matching (RQPM) in polycrystalline materials has been considered as an important technique for nonlinear optical frequency conversion, especially in wideband laser generation involving femtosecond lasers. In this paper, optical rectification (OR) based on RQPM in ZnSe ceramics was investigated for the first time, which could convert ultrashort optical pulses to broadband terahertz waves. A theoretical model of RQPM OR was built, with which the effects of material grain size, thickness, pump wavelength and pump pulse duration on terahertz generation, were simulated and discussed. It was found that RQPM OR in ZnSe is indeed effective in terahertz generation but insensitive to the material grain size and pump wavelength RQPM OR is even better than traditional single crystals such as ZnTe in bandwidth and robustness. The results can be a reference to optimize the RQPM OR nonlinear process, and hopefully, this work will promote the application of costless polycrystalline materials in the hot field of terahertz generation.

Introducing Spontaneously Phase‐Separated Heterogeneous Interfaces Enables Low Power Consumption and High Reliability for Phase Change Memory

AbstractPhase‐change memory is one of the most promising candidates for the next generation nonvolatile memory, but their high power consumption and low reliability remain bottleneck problems that limit the data storage density and its storage‐class memory application. Here, an innovative phase change material with embedded self‐precipitated interfaces, where the nanoscale grains of phase change material are cut into interconnecting “crystal islands” by thermally stable self‐precipitated material with low thermal conductivity, is proposed. The precipitated material provides both thermal and atomic migration confinements in three dimensions. The thermal confinement enables low power consumption, and the atomic migration confinement enables high device reliability. The devices based on spontaneously phase‐separated O‐doped Sb2Te3 verify the material design, where Sb oxide acts as the precipitated heterogeneous phase and Sb–Te alloy as the phase change material. O‐doped Sb2Te3 device with 250 nm hole diameter shows an ultralow power consumption, down to a few hundreds of femtojoule, which is comparable with those of phase change nanowires. Besides, good thermal stability and low resistivity drift (drift coefficient 0.005) as well as excellent cycle endurance up to 108 times are also obtained at the same time. The doping fabrication process is quite compatible with current semiconductor industry.

Investigation of microstructural and mechanical properties of Al alloy 7075-T6/B4C nanocomposite concocted via friction stir process

Magnanimously Aluminium metal matrix composites (MMCs) are acknowledged worldwide for keeping exceptional strength to weight ratio for which these are incorporated extensively in Aerospace and Automobile industries and gained potential limelight. Moreover, the material response outreach potential or the composite functionality potential are exclusively driven by tuning of the reinforcement materials. Herein, Al composites were concocted by introducing micro and nano Boron Carbide (B4C) powder into aluminium alloy AA 7075-T6 material matrix through Friction Stir Processing (FSP) with a motivation to enhance the mechanical and damping properties. Further the influence of physical structure alteration of reinforcement B4C from micro to nano dimension on the composites were validated through various characterizations. The microstructure of the composites was observed with optical microscope and Electron back scattered diffraction (EBSD) methods respectively. A significant grain refinement was observed with nano-reinforced composite by clinching average grain size reduced to 2.9 μm relative to base material grain size of 37 μm. The average hardness of nano-reinforced MMCs was found to be 66% higher than base material recorded a value of 141 HV. Furthermore, the AA7075-T6 composites were studied for their thermal and mechanical cyclic damping performance in the temperature range from ─ 60 to 60 °C and depicted exceptionally good damping property.

A test of the Threshing Machine (LMS Type) at Different Feed Rates and Speeds on Some Corn Properties

The effect of threshing machine (LMS type) on corn/ Sarah cultivar was studied based on some technical indicators. were tested under three feed rates (6A, 8A and 10A) and two level of speed 200 and 300rpm. in this experiment used complete randomized design (CRD) with three replications, according to Genstat software. The results showed that the feed rate 6A was major effect than other two levels of 8A and 10A in all studied conditions. Fine material ratio (FR), breakage ratio (BR), threshing efficiency (TE), grain damage (GD) and grain cleanliness (GC). The 200 rpm speed was meaningfully greater from the other level of 300 rpm speed in all studied conditions.

In-situ EBSD investigation of the effect of orientation on plastic deformation behavior of a single crystal superalloy

The plastic deformation behavior of three various orientation specimens of a nickel-based single-crystal (SX) superalloy were investigated by in-situ electron back-scattered diffraction (EBSD) at room temperature. Tensile properties, slip morphology, the evolution of Schmid factor, lattice rotation, and local strain were thoroughly discussed. In [1 1 13] specimen, the interaction of multi slip behavior induced local strain concentration, which restricted the plasticity but enhanced the strain hardening. Due to the single slip behavior, lower tensile strength and higher elongation were discovered in [9 1 7] and [2 1 3] specimens. Furthermore, during the plastic deformation of [1 1 13] specimen, lattice rotation is confined around [0 0 1] pole and shows a dispersive distribution, which is triggered by the multi slip behavior. A modified Sachs model considering multi slip behavior has been developed to predict the lattice rotation, this model is also applicable to severely deformed grains in polycrystalline materials.

Turning Molecular Springs into Nano-Shock Absorbers: The Effect of Macroscopic Morphology and Crystal Size on the Dynamic Hysteresis of Water Intrusion-Extrusion into-from Hydrophobic Nanopores.

Controlling the pressure at which liquids intrude (wet) and extrude (dry) a nanopore is of paramount importance for a broad range of applications, such as energy conversion, catalysis, chromatography, separation, ionic channels, and many more. To tune these characteristics, one typically acts on the chemical nature of the system or pore size. In this work, we propose an alternative route for controlling both intrusion and extrusion pressures via proper arrangement of the grains of the nanoporous material. To prove the concept, dynamic intrusion–extrusion cycles for powdered and monolithic ZIF-8 metal–organic framework were conducted by means of water porosimetry and in operando neutron scattering. We report a drastic increase in intrusion–extrusion dynamic hysteresis when going from a fine powder to a dense monolith configuration, transforming an intermediate performance of the ZIF-8 + water system (poor molecular spring) into a desirable shock-absorber with more than 1 order of magnitude enhancement of dissipated energy per cycle. The obtained results are supported by MD simulations and pave the way for an alternative methodology of tuning intrusion–extrusion pressure using a macroscopic arrangement of nanoporous material.

On the Modeling of Polycrystalline Ferroelectric Thin Films: Landau-Based Models Versus Monte Carlo-Based Models Versus Experiment

Due to the potential for technological application, there has been an explosion of interest in heavily polycrystalline ferroelectric nanofilms, such as those of doped hafnium oxide. However, the heavily polycrystalline nature of these materials invalidates conventional modeling approaches as the dynamics have been found to be: 1) nucleation-limited; 2) involve grains of ferroelectric material interspersed among grains of alternative, nonferroelectric material; and 3) the direct interaction between these grains is observed to be minimal. In this article, we consider seven separate compact or “0-D” models of such polycrystalline films. Four of these models are based on a Landau paradigm and two are based on a Monte Carlo (MC) paradigm. The seventh is the traditional Preisach model. Although all of these models have been used in the literature to model novel polycrystalline ferroelectric nanofilms, here we compare and contrast the accuracy and physical appropriateness of each model by comparing both their static and dynamic properties against experimental data. We then find that although all models except single-grain models are capable of reproducing the static properties, only the MC models replicate the long-time dynamical properties. Thus, it is demonstrated that not all models are equally valid for the accurate modeling of such films.

Early detection of high temperature hydrogen attack using the ultrasonic full matrix capture and advanced post-processing methods

In this work, advanced ultrasonic algorithms are studied for the detection of early-stage High Temperature Hydrogen Attack (HTHA). This degradation mechanism occurs when hydrogen reacts with carbon or carbides to create micro voids in the samples that degrade mechanical properties. Full matrix captures were postprocessed into scattering matrices and using advanced Total Focusing Methods (TFM) such as Delay Multiply and Sum (DMAS), weighted images and amplitude-free images. The main objective of this work is to detect HTHA when micro voids are not yet linked. For this purpose, finite element simulations are used to model HTHA degradation and noise generated by the grains in carbon steel material. Amplitude-free imaging methods showed promising results for low noise material. When using weighted images or DMAS in materials with stronger grain boundary noise, the amplitude of indications associated with HTHA was up to 272% above standard TFM. Finally, the scattering matrix provided the earliest detection for all the simulated configurations. These results were then validated with measurements made on three field samples extracted from equipment with HTHA damage. The level of HTHA of the three samples was confirmed with a metallographic study.

Shale Mineralogy Analysis Method: Quantitative Correction of Minerals Using QEMSCAN Based on MAPS Technology

Shale is of strong heterogeneity. The mineral composition has a significant influence on the diagenetic evolution, pore network formation, hydrocarbon content, oil mobility, and reservoir stimulation of shale. Accurate mineral analysis of shale is an essential precondition for scientific research and industrial production. In this study, we present a new quantitative method for shale mineral analysis based on high-resolution images, using a combination of QEMSCAN and MAPS technology. We overcome the problem of errors between the morphology and content of certain minerals identified by QEMSCAN technology and the actual results and take full advantage of high-resolution large-scale backscatter scanning electron microscopy (MAPS technology) to process clay-grade mineral image data with complex contact relationships. Specifically, we realize the correction of QEMSCAN mineral quantitative analysis results through image smoothing, image alignment, image segmentation, morphological analysis, and other image processing technologies. The method enables the precise and fast measurement of mineral types, contents, and two-dimensional (2D) distributions. It provides a more credible result consistent with geological reality than QEMSCAN. A straightforward application of the new method is refined mineralogical analysis, including the characterization of pores, fractures, organic matter, and/or mineral grains in geological materials.

Mechanical Behavior and Microstructure Evolution during Hot Torsion Deformation of Aluminum Alloy AA2219

This study comprehensively analyzes the mechanical behavior and microstructural evolution of aluminum alloy AA2219‐T87 undergoing high deformation and strain rates at elevated temperatures via hot torsion tests. An integrated experimental and modeling approach is employed, where a finite element model (FEM) is developed with ABAQUS to address local deformation and nonuniform temperature distribution along the specimen gauge section. A Johnson–Cook constitutive material model is calibrated based on the calculated and measured torque curves at different conditions. The grain structure distribution is characterized through optical microscopy and electron backscatter diffraction (EBSD) analysis. Combined with the ABAQUS calculated local thermomechanical conditions, microstructure modeling, using established literature‐based equations, is established to provide insights into grain size distribution and recrystallization mechanisms. The calibrated material constitutive model, recrystallization model, and grain size model can be utilized to model various manufacturing processes, which involve hot deformation of aluminum alloys in the intermediate strain rate range of 14–78 s−1. The constitutive model shows adequate matching of the experimental torque curves at 400, 450, and 500 °C. The recrystallization prediction model functions at over 94% accuracy and the grain size model provides an average deviation between predicted and measured grain size reduction of 11.5%.

Numerical analysis of rolling contact fatigue crack initiation Considering material microstructure

The material microstructure of plays an important role in crack initiation of rolling contact fatigue. To address crack initiation of tapered roller bearings, the inhomogeneous characteristic of material is considered. The random distribution of material grains is simulated with Voronoi graph, and a Voronoi finite element model of rolling contact fatigue is given. Numerical analysis of damage-life constitutive relation is carried out with finite element analysis. The effect of material microstructure inhomogeneity on initiation life of fatigue crack is studied. Researches show that the smaller the grain size, the more difficult the fatigue crack appearing. The larger the difference of elasticity modulus between non-metallic inclusions and matrix material, the greater the impact on fatigue life of crack initiation. The angular and sharp non-metallic inclusions reduce fatigue life more than rounded shape inclusions. Initiation life of fatigue crack has a minimum value on a critical depth of nonmetallic inclusion. The longer distance between two laterally arranged inclusions, the greater it affect the initiation life of fatigue crack. The effect of distance between two vertically arranged inclusions on fatigue crack initiate depends on the depth of inclusions.