Composition Gradient Research Articles

High‐Throughput Optimization of Magnetoresistance Materials Based on Lock‐In Thermography

AbstractWith the giant magnetoresistance (GMR) effect serving as a vital component in modern spintronic technologies, researchers are dedicating significant efforts to improve the performance of GMR devices through material exploration and design optimization. However, traditional GMR measurement approaches are inefficient for comprehensive material and device optimization. This study proposes a high‐throughput current‐in‐plane GMR measurement technique based on thermal imaging of Joule heating utilizing lock‐in thermography (LIT). This LIT‐based technique is advantageous for efficiently evaluating films with varying compositions and thickness gradients, which is crucial for ongoing material exploration and design optimization to enhance the GMR ratio. First, it is demonstrated that using CoFe/Cu multilayers, the simple Joule heating measurement based on LIT enables quantitative estimation of the GMR ratio. Then, to confirm the usefulness of the proposed method in high‐throughput material screening, a case study is shown to investigate the GMR of CoCu‐based granular films with a composition gradient. These techniques allow to determine the optimum composition with maximum GMR ratio using the single composition‐gradient film and reveal Co22Cu78 as the optimal composition, yielding the largest GMR ratio among the reported polycrystalline CoCu‐based granular films. This demonstration accelerates the material and structural optimization of GMR devices.

Origins of twin boundaries in additive manufactured stainless steels

316L and 304L stainless steels and a compositional gradient of both are fabricated using the same processing parameters via laser directed energy deposition additive manufacturing. In those alloys, the increase in chromium-to-nickel ratio is accompanied with grain refinement and formation of a high density of twin boundaries, i.e. Σ3 boundaries. By means of electron microscopy, crystallographic and thermodynamic calculations, we demonstrate that two mechanisms arising from the ferrite-to-austenite solidification mode are at the origin of twin boundary formation and grain refinement: (1) inter-variant boundaries emerging from the encounter of pairs of austenite grains formed from a common ferrite orientation with Kurdjumov–Sachs orientation relationship; (2) icosahedral short-range-ordering-induced (ISRO) nucleation of twin-related γ grains directly from the solidifying liquid. These findings define new routes to achieve grain boundary engineering in a single step in FeCrNi alloys, by tailoring the solidification pathway during the AM process, enabling the design of functionally graded materials with site-specific properties.

Superwetting Nanofluids of NiOx-Nanocrystals/CsBr Solution for Fabricating Quality NiOx-CsPbBr3 Gradient Hybrid Film in Carbon-Based Perovskite Solar Cells.

The wettability of precursor solution on substrates is the critical factor for fabricating quality film. In this work, superwetting nanofluids (NFs) of non-stoichiometric nickel oxide (NiOx) nanocrystals (NCs)-CsBr solution are first utilized to fabricate quality NiOx-CsPbBr3 hybrid film with gradient-distributed NiOx NCs in the upper part for constructing hole transport ladder in carbon-based perovskite solar cells (C-PSCs). As anticipated, the crystalline properties (improved crystalline grain diameters and reduced impurity phase) and hole extraction/transport of the NiOx-CsPbBr3 hybrid film are improved after incorporating NiOx NCs into CsPbBr3. This originates from the superb wettability of NiOx-CsBr NFs on substrates and the excellent hole-transport properties of NiOx. Consequently, the C-PSCs with the structure of FTO/SnO2/NiOx-CsPbBr3/C displays a power conversion efficiency of 10.07%, resulting in a 23.6% improvement as compared with the pristine CsPbBr3 cell. This work opens up a promising strategy to improve the absorber layer in PSCs by incorporating NCs into perovskite layers through the use of the superwettability of NFs and by composition gradient engineering.

Microstructure evolution and local mechanical properties of friction stir additively manufactured (FSAM) AA5083/AA6061/AA7075 gradient composite

The current study is focused on the successful fabrication and characterization of microstructure and properties gradient composite made of 3 mm thick sheets of AA5083-O, AA6061-T6, and AA7075-T6 alloys using friction stir additive manufacturing (FSAM) technique. Two combinations of four layered FSAM builds (6756 and 7567) were fabricated successfully without any major defects at the optimized process parameters of 850 rpm (tool rotational speed) and 55 mm/min (tool transverse speed). The material mixing, interfacial bonding features, microstructure evolution, and mechanical performance within the stir zones (SZ) were thoroughly examined using advanced characterization techniques. Electron backscatter diffraction (EBSD) analysis confirmed a gradient microstructure along the build depth in both FSAM builds, with average grain sizes decreasing from 52 μm (AA5083), 46 μm (AA6061), and 40 μm (AA7075) in base metals to ∼ 4–7 μm within the SZ. The remarkable grain refinement within the SZ was mainly attributed to the dominant presence of the continuous dynamic recrystallization (CDRX) mechanism. Texture analysis corresponding to pole figures (PFs) and orientation distribution function (ODF) plots reveals the crystallographic texture evolution along the build depth. The prevalent existence of B/ B‾ and C textures throughout all regions of the FSAM builds affirms the presence of ample shear strain during the FSAM procedure. Through thickness miniature tensile and microhardness tests depict the gradient in mechanical performance for both the FSAM builds along the build depth. Microhardness gradients in the range from ∼ 80 HV0.1 to ∼ 145 HV0.1 were observed along the build depth. The axial sample in the build direction shows appreciable strength (265 MPa and 224 MPa) and uniform elongation (28 % and 24 %) for 6756 and 7567 FSAM build, respectively. Furthermore, remarkable strain hardening behaviour corresponding to hardening capacity (Hc) and hardening exponent (n) was noticed for both the axial build samples compared to AA6061-T6 and AA7075-T6 base metals. These findings underscore the potential of FSAM in fabricating functionally gradient composite materials tailored to specific functional requirements.

Laser chemical vapor deposition of TiC fibers and tubes

Laser Chemical Vapor Deposition (LCVD) is a process in which fibers are deposited from a gaseous precursor to a solid phase under a traversing laser focal point. Here, we grow titanium carbide (TiC) fibers and tubes dependent upon a hyperbaric hydrogen-rich, hydrogen-balanced, and hydrogen-lean environment referenced to a titanium tetrachloride and ethylene gas mixture under three different laser intensities. X-ray diffraction confirms the deposition of TiC with energy dispersive spectroscopy noting a radial compositional gradient of titanium and carbon in the diameter of the deposit. Depending on the hydrogen concentration, the TiC encased a core carbon-rich fiber or formed a hollow tube, with these formations explained by thermophoresis. Furthermore, depending on the gas mixture and laser intensity, the carbon-rich interior and TiC outer shell exhibited different morphologies that are discussed in terms of growth rate regimes. The collective outcomes demonstrate the complex processing space in forming ceramic materials by LCVD.

Effect of thermodiffusion on compositional grading in hydrocarbon reservoirs: Insights from field cases and simulations

Heterogeneity of fluid composition in vertical and lateral directions is observed in many reservoirs, known as compositional grading. It is necessary to evaluate the diffusion forces for modeling this phenomenon. In addition to the chemical and gravity forces, the temperature gradient causes mass diffusion. In the present investigation, the accuracy and reliability of the Haase theory and the Shukla-Firoozabadi method in thermodiffusion modeling are studied comprehensively using field samples from light to heavy-oil reservoirs. On the one hand, the Shukla-Firoozabadi model results in compositional grading reduction by thermodiffusion; on the other hand, the Haase theory reveals enhancement and attenuation effects of thermodiffusion depending on reference enthalpy quantification. A new approach, which employs the reference enthalpies of pseudocomponents as tuning parameters, is proposed to improve the results of the Haase theory. The proposed procedure is also validated using field cases. In addition, the experimental field information compared with isothermal and nonisothermal models are studied to answer the question of "how" and to "what extent" thermodiffusion contributes to compositional grading. Results demonstrated the limited attenuation effect of thermodiffusion in light oils, while this phenomenon leads to severe enhancement of compositional grading in the medium and heavy-oil reservoirs. In heavy oils, the thermodiffusion effect is more pronounced on heavy pseudocomponents rather than light paraffinic species. Finally, the practice of compositional gradient model optimization, which is of particular interest to reduce the uncertainty in fluid initialization and to address reservoir compartmentalization, is presented.

Impact resistance behaviors of boride reinforced Ti-6Al-4 V functionally graded materials: Experimental and numerical analysis

The impact resistant behaviors of boride reinforced Ti-6Al-4 V functionally graded materials prepared by spark plasma sintering (SPS) with compositional gradients of 90°, 84°, 82°and 79° were investigated based on the experimental test and the finite element method. The material constitutive parameters of the boride reinforced Ti-6Al-4 V alloys with different TiB2 contents were determined, and the Johnson Holmquist Ceramics (JH-2) model and a cohesive contact model were established and developed to predict the crack propagation and the impact resistance behaviors of the materials. The calculated results agreed well with the split Hopkinson press bar (SHPB) experimental results. The optimum material composition gradient design scheme with a continuous transition property from a high-toughness end to a high-strength end along the thin-thickness direction was determined. The G84 (0, 0, 15, 30 wt% TiB2) had the best impact resistance, with Young's modulus of 55505±5 GPa, compressive strength of 2045±5 MPa, and microhardness ranging from 535±5HV to 1246±5HV, exhibiting high strength and hardness at a high-strength end that can prolong the interaction time between the impactor and the materials, while the elongation of 39 % at its high-toughness end can cause tensile deformation, consuming impact kinetic energy efficiently. Combined with the experimental and numerical analysis results, the impact resistance and the crack-alleviated mechanisms of boride reinforced Ti-6Al-4 V functionally graded materials were discussed. Reducing the compositional gradient can alleviate the difference in coefficients of thermal expansion between composites, which may lead to strengthen the reflected wave, lower the compression wave, and suppress high-strength end failure efficiently, meaning of relieving the stress concentration under extreme service conditions. Moreover, the effects of the presence of the borides, such as in situ-formed TiB, remained TiB2at al., the dislocation defects and the whisker-like TiB on the armour materials resist fracture and layer cracking were also analyzed. This work provided a method for designing high performance of boride reinforced Ti-6Al-4 V functionally graded materials with high impact resistance and thin thickness.

The use of He buffer gas for moderating the plume kinetic energy during Nd:YAG-PLD growth of EuxY2−xO3 phosphor films

We have investigated the He buffer gas process of moderating the kinetic energy of the pulsed laser deposition (PLD) plume during EuxY2−xO3 phosphor film growth. When using a neodymium yttrium aluminum garnet laser for PLD thin film growth, the kinetic energy of the ablation plumes can be high enough to cause the formation of point defects in the film. The buffer gas pressure is an important process parameter in PLD film growth. We find that the presence of the He buffer gas reduces the kinetic energy of the laser deposition plume through many low-angle collisions in the gas phase by a factor of 7 without reducing the deposition rate. This is because He is much lighter than any of the elements in the plume and it does not affect the composition of the oxide films. Consequently, the resputtering of the Y2O3 film surface by the plume was significantly suppressed in the presence of the He gas moderator, leading to a decrease of the defect density in the Y2O3 films. The improvement of the film quality was verified by a systematic analysis of time-resolved photoluminescence (PL) data for EuxY2−xO3 composition–gradient films. The PL lifetime and intensity of Eu0.2Y1.8O3, which shows the highest PL intensity, increased by 13.3% and 36.4%, respectively, when the He gas moderation process was used. The He buffer gas process is applicable to the PLD growth of the other oxide materials as well, where the reduction of the kinetic energy of the plume would bring the PLD process closer to the molecular beam epitaxy growth condition.

Differential associations of five riverine organism groups with multiple stressors

The decline of river and stream biodiversity results from multiple simultaneous occuring stressors, yet few studies explore responses explore responses across various taxonomic groups at the same locations. In this study, we address this shortcoming by using a coherent data set to study the association of nine commonly occurring stressors (five chemical, one morphological and three hydraulic) with five taxonomic groups (bacteria, fungi, diatoms, macro-invertebrates and fish). According to studies on single taxonomic groups, we hypothesise that gradients of chemical stressors structure community composition of all taxonomic groups, while gradients of hydraulic and morphological stressors are mainly related to larger organisms such as benthic macro-invertebrates and fish.Organisms were sampled over two years at 20 sites in two catchments: a recently restored urban lowland catchment (Boye) and a moderately disturbed rural mountainous catchment (Kinzig). Dissimilarity matrices were computed for each taxonomic group within a catchment. Taxonomic dissimilarities between sites were linked to stressor dissimilarities using multivariable Generalized Linear Mixed Models.Stressor gradients were longer in the Boye, but did in contrast to the Kinzig not cover low stress intensities. Accordingly, responses of the taxonomic groups were stronger in the Kinzig catchment than in the recently restored Boye catchment. The discrepancy between catchments underlines that associations to stressors strongly depend on which part of the stressor gradient is covered in a catchment. All taxonomic groups were related to conductivity. Bacteria, fungi and macro-invertebrates change with dissolved oxygen, and bacteria and fungi with total nitrogen. Morphological and hydraulic stressors had minor correlations with bacteria, fungi and diatoms, while macro-invertebrates were strongly related to fine sediment and discharge, and fish to high flow peaks. The results partly support our hypotheses about the differential associations of the different taxonomic groups with the stressors.

High-Throughput Multi-Principal Element Alloy Exploration Using a Novel Composition Gradient Sintering Technique

This work demonstrates the capabilities and advantages of a novel sintering technique to fabricate bulk composition gradient materials. Pressure distribution calculations were used to compare several tooling geometries for use with current-activated, pressure-assisted densification or spark plasma sintering to densify a gradient along the long dimension of the specimen. The selected rectangular tooling design retains a low aspect ratio to ensure a uniform pressure distribution during consolidation by using a side loading configuration to form the gradient along the longest dimension. Composition gradients of NixCu1−x, MoxNb1−x, and MoNbTaWHfx (x from 0 to 1) were fabricated with the tooling. The microstructure, composition, and crystal structure were characterized along the gradient in the as-sintered condition and after annealing to partially homogenize the layers. The successful fabrication of a composition gradient in a difficult-to-process material like the refractory multi-principal element alloy system MoNbTaWHfx shows the utility of this approach for high-throughput screening of large material composition spaces.

Preferential composition during nucleation and growth in multi-principal element alloys

The crystallization of complex, concentrated alloys can result in atomic-level short-range order, composition gradients, and phase separation. These features govern the properties of the resulting alloy. While nucleation and growth in single-element metals are well understood, several open questions remain regarding the crystallization of multi-principal component alloys. We use molecular dynamics to model the crystallization of a five-element, equiatomic alloy modeled after CoCrCuFeNi upon cooling from the melt. Stochastic, homogeneous nucleation results in nuclei with a biased composition distribution, rich in Fe and Co. This deviation from the random sampling of the overall composition is driven by the internal energy and affects nuclei of a wide range of sizes, from tens of atoms all the way to super-critical sizes. This results in short-range order and compositional gradients at nanometer scales.

Control of microstructure, defects and mechanical properties in direct energy deposited SS316L/Inconel 718 functionally graded material via mechanical vibration

In this study, a mechanical vibration assisted laser direct energy deposition was used to fabricate a functionally graded material composed of stainless steel 316L and Inconel 718. The effect of mechanical vibration on the microstructure, defects and mechanical properties of the prepared functionally graded material was studied. The results indicate that in the sample without the assistance of mechanical vibration, plenty of brittle Laves phase and NbC carbides form and induce the cracking in the specific compositional gradient range from 60 % stainless steel 316L/40 % Inconel 718 to 40 % stainless steel 316L/60 % Inconel 718. The Vickers hardness obtains a minimal value near the compositional region of 50 % stainless steel 316L/50 % Inconel 718. The tensile properties are terrible with an ultimate tensile strength of 309.7 MPa and an elongation of 7.8 %. In the sample with the assistance of mechanical vibration, the synchronous mechanical vibration could effectively restrain the cracks formation in the compositional gradient region by suppressing the brittle phases precipitation, weakening the dislocation aggregation and refining the grain size, and resultantly achieve decent tensile properties with an ultimate tensile strength of 642.6 MPa and an elongation of 22.4 % and significantly improve the deterioration of hardness in the compositional gradient region.

Ultrafast bimetallic interface reinforcement in additively manufactured multi-material via electropulsing

The bimetallic interface in additively manufactured multi-material was subjected to intense thermal cycling, and thus forming sizable heat affected zone and drastic mutation of chemical component, which led to weak metallurgical bonding. In this investigation, the pulsed current (1255 Hz; 64 μs; 35.4 V; 191 A; 1000 ℃; 20 min) was used to rapidly broaden the compositional mutation zone from 16 μm to 45 μm, and the heat affected zone was completely eliminated. However, the roles of equivalent heat treatment (1000 ℃; 20 min) were opposite with the pulsed one. The width of compositional mutation zone became narrower and the morphology heat affected zone did not change after equivalent heat treatment. Furthermore, the hot compression experiment proved the better bimetallic interface quality of pulsed sample. The rapid regulation of microstructure and composition gradient is caused by increasing interfacial diffusion flux and the promotion of electron wind force to the solute atom.

Garnet stability during crustal melting: Implications for chemical mohometry and secular change in arc magmatism and continent formation

Understanding how new felsic crust is formed and subsequently evolves through time is critical to identifying the geodynamic regimes that have dominated various parts of Earth history, and have important implications for feedbacks between the lithosphere and biosphere, such as controlling the influx of continental detritus into the oceans. In recent years, several trace element-based geochemical proxies have been proposed to allow determination of paleo-crustal thicknesses, which have been calibrated primarily using data collected from modern-day arcs. The application of these proxies through deep time has revealed surprising results, including the suggestion that the mid-Proterozoic continents were atypically thin compared to those in the Archean and the Phanerozoic; however, a range of factors may influence commonly cited trace element ratios (e.g. Sr/Y) rather than just crustal depth, leading to additional and unexpected magnitudes of uncertainty. Here we perform geochemical modelling to deduce the effect of variable bulk-rock composition and geothermal gradient on the trace element signature of felsic melts generated in arc systems. Using a range of protoliths representative of deep arc crust, the results show that considerable care must be taken when analysing simple trace element ratios of granitoid melts and making direct interpretations of the pressure of crystallisation. In particular, changes in geothermal gradients and differences in arc basalt composition impart strong controls on the relative stability of garnet and plagioclase during metamorphism and partial melting, and wide ranges of Sr/Y and La/Yb may be produced in derivative felsic melts produced at the same crustal depth. The interpretation of mid-Proterozoic continental arcs being atypically thin may instead be an artefact of underestimation of the active geothermal gradient at the time of magma formation, which acts to reduce Sr/Y and La/Yb ratios, even in normal thickness (∼35–40 km) crust. Furthermore, we argue that the potentially garnet-free residua during the formation of mid-Proterozoic felsic magmas points to crust formation without lower crustal foundering, and thus, that this commonly invoked paradigm for formation of the continental crust may only be applicable to certain periods of Earth history.

Fabrication and Characterization of Functionally Graded Nanocomposites: Impact of Graphene and Vanadium Carbide on Aluminum Matrix

Abstract Functional graded nanocomposites (FGNCs) based on Al are artificially tailored heterogeneous materials intended to serve the demand for diverse and contradicting properties used in various industrial applications. FGNCs and hybrid FGNCs (HFGNCs) based on Al reinforced with graphene and vanadium carbide (VC) were prepared using powder metallurgy techniques and investigated. Both samples were designed with a gradient composition, where the bottom layer consisted of 100% pure Al, followed by three consecutive layers containing progressively increasing amounts of reinforcement. The incorporation of graphene and VC into layer powders resulted in a decrease in both particle and crystal dimensions compared to pure Al. Adding graphene has a negative effect on bulk density samples, while VC has a positive effect. Reinforcing materials led to a decrease in thermal conductivity that reached 26.7 % for samples reinforced with VC reinforcement, except for FGNCs reinforced with graphene, which increased by ~3.3 compared to Al. The samples’ CTE and electrical conductivity values decreased, although adding graphene alone led to a slight decrease in electrical conductivity. A significant improvement in all mechanical properties was noted with additional. The HFGCNs reinforced with the largest amount of hybrid reinforcement recorded an improvement in CTE value, Young's modulus, and compressive strength by about 38.1%, 22.2%, and 20.5%, respectively, compared to Al

Comparison of ELSD and RID combined with HPLC for simultaneous determination of six rare sugars in food components

Evaporative light scattering detection (ELSD) and refractive index detection (RID) are two methods commonly used in high-performance liquid chromatography (HPLC) to quantitatively analyze sugars. The performance of two detectors for the detection and quantification of six rare sugars in food samples is systematically compared in this paper. Erythritol, allulose, tagatose, mannitol, isomaltulose and trehalose were separated by HPLC on an NH2 chromatographic column using a flow gradient or isocratic composition acetonitrile–water (80:20, v/v) as mobile phase. The analytical signals for six rare sugars were obtained using ELSD and RID. The intra-day and inter-day variations were lower 3.9 % and 3.5 % for ELSD and 2.4 % and 3.6 % for RID, respectively. The limits of detection (LODs) were between 0.02 mg·mL−1 and 0.06 mg·mL−1 for ELSD in the range of 0.06–0.6 mg·mL−1. The LODs of RID were between 0.1 mg·mL−1 and 1.0 mg·mL−1 within a wider dynamic range (0.4–80 mg·mL−1). The optimized method was used to analyze seven samples. Although both methods can be used for the detection of six rare sugars, the selectivity of isomaltulose and the detection results of six rare sugars under the HPLC-RID method are not as good as the HPLC-ELSD method. Therefore, the HPLC-ELSD method is more suitable for the detection of six rare sugars in food.

Formation mechanism of surface gradient microstructure and mechanical properties evolution of Mg–Y-Nd-Gd-Zr alloy by ultrasonic rolling

The evolution mechanism of the microstructure and mechanical properties of a Mg–Y-Nd-Gd-Zr alloy subjected to different numbers of passes of the ultrasonic surface rolling process (USRP) was investigated. The results demonstrated an initial decrease followed by an increase in the surface roughness of the alloy. The optimal surface roughness was achieved after four passes, with a contour mean deviation of 0.06 μm and micro-roughness 10-point height of 0.55 μm. After the USRP, the alloy exhibited a composite gradient structure characterized by increased grain size and decreased dislocation, lamination, and twin densities. The depth of the gradient layer increased with each additional USRP pass, ranging from 650 μm (1 pass) to 910 μm (8 passes). Furthermore, the USRP treatment effectively enhanced the alloy strength; compared with the untreated samples; the yield strength increased by 34.2% in the gradient sample after one pass. No significant change was observed in the YS with an increasing number of rolling passes for Mg alloys, whereas both the tensile strength and elongation showed improvements. High-density twinning played a crucial role in enhancing the YS of the gradient samples without significant variation across different numbers of rolling passes, thus following a consistent pattern. The formation of more nanocrystals on the surface of Mg alloys after multiple rolling cycles is key to preventing premature fracture failure and improving the work-hardening rate.

Thermal processing of primordial pebbles in evolving protoplanetary disks

During protoplanetary disk formation, dust grains located in the outer disk retain their pristine icy composition, while solids in the inner stellar-heated disk undergo volatile loss. This process may have left a fossil record in Solar System material, showing different nucleosynthetic imprints that have been attributed to different degrees of thermal processing. However, it remains unclear how a large mass fraction of thermally processed inner-disk pebbles is produced and how these grains are subsequently transported throughout the disk. In this work, we numerically investigate the evolution in time of a two-component pebble disk consisting of both pristine pebbles and those that underwent ice sublimation. We find that stellar outbursts exceeding 1000 times the solar luminosity are efficient in thermally altering, through ice sublimation, a large mass fraction of pebbles (around 80%). After the establishment of this initial radial dust composition gradient throughout the disk, the subsequent mixing and inward drift of pristine outer-disk pebbles alter the inner disk bulk composition from processed to more unprocessed in time. Therefore, if processed pebbles without ice mantles have an isotopic composition similar to ureilite meteorites from the inner Solar System, inner-disk minor bodies forming from the early pebble flux (<1 Myr) will be isotopically ureilite-like, while later-formed bodies will be increasingly admixed with the signature of the lateincoming, CI chondrite-like unprocessed pebbles. This appears to be largely consistent with the trend seen between the accretion age of different meteoric classes and their different stable isotope composition anomalies (in μ54Cr, μ48Ca, μ30Si, and μ58Ni), but further work may be needed to explain the role of isotopically anomalous refractory inclusions and anomaly trends in other elements. Our findings further support an early thermal processing of ice mantles via stellar outbursts that are common around young Sun-like stars.

The screening of reasonable copper and phosphorus content in weathering steel by a high-throughput experimental method

The effect of coupling of copper and phosphorus in steel on atmospheric corrosion behavior was investigated using high-throughput experimental methods. Wire beam electrodes and plates with discrete distribution of composition gradients were prepared through a selective laser melting method. By combining array electrode scanning tests and EPMA, the electrochemical properties and the relationship between different copper and phosphorus contents were rapidly determined. Plenty of data obtained were analyzed according to relevant standards and screened to identify compositional ranges corresponding with the relevant compositions of existing grades of steel. To further analyze the effect of copper and phosphorus on the corrosion behavior, dry/wet cyclic corrosion test were performed using plates. A combination of XRD, FTIR, SEM, EDS, and EPMA were used to analyze the corrosion behavior. It was observed that both copper and phosphorus promoted the formation of amorphous substances, supporting the proposed mechanism by previous researchers. Furthermore, in the absence of manganese interference, copper could accumulate at the metal/rust layer interface, rendering the rust layer cation-selective and effectively inhibiting the deep penetration of chloride ions. Moving forward, we expect to develop this high-throughput experiments to investigate the coupling effects of other elements on corrosion behavior.

Thin-film memristor using an amorphous metal–oxide semiconductor with a gradient composition of conducting components

A thin-film memristor using an amorphous metal–oxide semiconductor (AOS) with a gradient composition of conducting components has been developed, which is another way to achieve memristive properties. The advantages are that conductivity distribution is already obtained as fabricated without forming operation, and an analog characteristic is obtained by optimizing the component composition in AOS. As the binary characteristic, the set operation induces the transition from a low conductance state to a high conductance state, whereas the reset operation does vice-versa. The switching ratio (SR) is high, 448. As the analog characteristic, the SR becomes greater rapidly as the V set increases, namely, the dynamic range is outstanding.