Alloy Core Research Articles

NixCo1-x@NixCo1-xO/NCNT as Trifunctional ORR, OER, and HER Electrocatalysts and its Application in a Zn-Air Battery.

The efficient electrochemical conversion and storage devices can be boosted by the development of cost-effective and durable electrocatalysts. However, simultaneous in-depth understanding of the reaction mechanism is also required. Herein, we report the preparation, characterization, and electrochemical activities of bimetallic NixCo1-x NPs and core-shell NixCo1-x@NixCo1-xO NPs stabilized on N-doped carbon nanotubes (NCNTs). The electrocatalyst is derived from a bimetallic MOF {[Ni0.5Co0.5(bpe)2(N(CN)2)](N(CN)2)·(5H2O)}n (1) via pyrolysis followed by calcination. Pyrolysis of the bimetallic MOF gives rise to bimetallic nanoparticles stabilized on NCNTs, which, when subsequently calcined, leads to the formation of a core-shell structure with a semiconducting oxide shell (NixCo1-xO) encapsulating the NixCo1-x bimetallic NP core. Detailed evaluation of the electrocatalytic performance of NixCo1-x@NixCo1-xO/NCNT proves its worth as a bifunctional catalyst with 380 mV overpotential for oxygen evolution reaction at 10 mA cm-2 current density and 0.87 V (vs RHE) onset for oxygen reduction reaction in the alkaline medium. Additionally, the prepared electrocatalyst efficiently catalyzes the hydrogen evolution reaction with a nominal overpotential of 74 mV (vs RHE) for reaching 10 mA cm-2 current density in acidic medium. The practical applicability of this catalyst is further upheld in the fabrication of a zinc-air battery having high specific capacity with high round-trip efficiency and adequate cycle life. DFT calculations establish that the structure of NixCo1-x@NixCo1-xO/NCNT is crucial for its electrochemical activity since it has the threefold advantages of cooperative charge transfer from Co to Ni, synergistic relationship between the conductive alloy core and semiconducting oxide shell, and a highly conductive N-doped CNT matrix.

From AuPd Nanoparticle Alloys towards Core‐Shell Motifs with Enhanced Alcohol Oxidation Activity

AbstractThe best activity of bimetallic AuPd nanoparticles for alcohol oxidation reaction is usually achieved by adjusting the Au/Pd molar ratio. Herein, alloy AuPd nanoparticles of ∼2.5–3.5 nm, ranging from Au‐rich to Pd‐rich compositions, were synthesized through a sol‐immobilization method. A calcination step under air conditions caused an increase in size up to 5.5 nm, but also driven the segregation of Pd to the surface, which generated an Au rich core with Pd on the shell. At high Pd content, the shell structure is formed by PdO. The catalytic activity of Pd‐rich samples (1 : 1, 1 : 2 and 1 : 4 Au : Pd) for benzyl alcohol oxidation increased ∼4‐fold after calcination. Upon reduction with H2, surface PdO motifs are reduced to Pd that did not dissolve back into the AuPd alloy core, maintaining the metallic Pd shell. The catalytic activity decreased. Therefore, restructuring alloyed AuPd nanoparticles into core‐shell like structures with PdO in the shell is beneficial to the catalytic activity, but reduction of PdO layer was detrimental. These results provide new insights on the optimization of AuPd catalysts, considering not only the Au/Pd molar ratio, but also the importance of PdO, which was not anticipated in the previous literature.

Experimental and numerical study on the dynamic response of aluminum alloy wood sandwich panels under high-velocity impact

The purpose of this study was to investigate the high-velocity impact response and failure modes of three-layer sandwich panels consisting of aluminum alloy sheets and plywood. The energy absorption mechanism and interaction between the plywood core and aluminum alloy panels were investigated by a high-velocity impact test. Different types of bullets were used in the impact test, and impact velocity parameters were obtained using a high-velocity camera to assess damage patterns. A full-scale finite element model was established to simulate the response mode of plywood sandwich under high-velocity impact. After the finite element model was verified by the experimental results, the energy absorption of the sandwich structure was further discussed. The results showed that the sandwich structure provided better protection than the double-layer structure. The analysis and predictions were in good agreement with the experimental results and numerical calculations. The experimental and numerical studies proposed in this paper are expected to provide new references and ideas for the design of multilayer structures with better impact resistance and lightweight characteristics.

Design and verification of a high-gradient and high-power 2nd harmonic cavity for the China Spallation Neutron Source upgrade project

Here, we report our recent progress in the design, fluid thermodynamics simulation, and high-power test of the2nd harmonic cavity for the China Spallation Neutron Source Phase II. A high-performance and large-size magnetic alloy (MA) core was developed as the load material for the radiofrequency cavity to achieve a high gradient of 40 kV/m. The water-cooling structure and cooling efficiency were studied and improved through numerical analysis and thermal experiments. The long-term stability of the cavity, especially the waterproofness of the MA cores with high heat load, was verified by high power tests.

Study on localized corrosion behavior of hot extrusion deformed GW103K magnesium alloy

This study investigated the corrosion behavior in the core and at the edge of the cross-section of an extruded GW103K (Mg–10Gd–3Y–0.4Zr) alloy. Equivalent stress and strain were modeled using finite element simulations. The stress and strain in the core were lower than those at the edge. The microstructure, corrosion morphology, and grain orientation of the alloy were examined using optical microscopy, scanning electron microscopy, and electron backscatter diffraction, respectively. The results showed that most grains in the core exhibited a basal plane orientation and lower surface energy, whereas those at the edge exhibited cylindrical orientations. Hydrogen evolution experiments and electrochemical tests showed that the corrosion resistance in the core was higher than that at the edge. Scanning Kelvin probe force microscopy measurements of the surface potential distribution in the cross-section revealed a large potential difference between the second-phase particles at the edge and the matrix, with obvious galvanic corrosion. The alloy core exhibited low stress and a higher content of grains with basal plane orientation, along with a small potential difference between the second-phase particles and the matrix. Thus, the corrosion resistance in the core was higher than that at the edge.

Multifunctional Cu-Se Alloy Core Fibers and Micro-Nano Tapers.

Cu-Se alloy core fibers with glass cladding were fabricated by a thermal drawing method of a reactive molten core. The composition, crystallography, and photoelectric/thermoelectric performance of the fiber cores were investigated. The X-ray diffraction spectra of the Cu-Se alloy core fibers illustrate the fiber cores being polycrystalline with CuSe and Cu3Se2 phases. Interestingly, the fiber cores show a lower electrical conductivity under laser irradiation than under darkness at room temperature. Meanwhile, the fiber cores possess a power factor of ~1.2 mWm-1K-2 at room temperature, which is approaching the value of the high thermoelectric performance bulk of Cu2Se polycrystals. The flexible Cu-Se fibers and their micro-nano tapers have potential multifunctional applications in the field of photoelectric detection and thermoelectric conversion on curved surfaces.

Multicore-shell structure CuxCoy-Fe alloy nitrogen doped mesoporous hollow carbon nanotubes composites for oxygen reduction reaction

Carbon-based materials with transition metal modifications are the dominant materials for oxygen reduction reaction (ORR), but the synthesis in a simple and efficient way is still a great challenge. Herein, multicore-shell structure CuxCoy-Fe alloy nitrogen doped mesoporous hollow carbon nanotubes (N-MHCNT/CuxCoy-Fe@C) were designed and synthesized by a facile and environment-friendly method. In the process of pyrolysis, polypyrrole serving as the substrate to form N-doped hollow carbon nanotubes and the polydopamine (PDA) acts as the carbon and nitrogen source to form a shell structure. Additionally, the cubic CuxCoy-Fe MOFs synthesized at room temperature collapses to form multiple alloy cores. Notably, the mesoporous structure of N-MHCNT/CuxCoy-Fe@C enhances the mass transfer process, while the carbon shell protects the metal active sites. Moreover, mesoporous hollow carbon, rich M-Nx (M=Cu, Co, Fe) active sites, the synergistic effects between N-MHCNTs, CuxCoy-Fe alloys and multiple core-shell structures allowed N-MHCNT/Cu2Co1-Fe@C exhibited high activity and long-term durability in ORR. Besides, the RRDE tests confirms the reaction kinetics of N-MHCNT/Cu2Co1-Fe@C as a mainly 4-electron reaction with an electron transfer number of 3.78 (Pt/C is 3.86) and a low hydrogen peroxide yield of 16%. This work provides a new strategy for the development of non-precious metal ORR catalysts by rational structural design and metal ratio adjustment.

Numerical Analysis of Double-Leaf Composite Stiffened Door Subjected to Blast Loading

Doors are the most critical part in any structure as they may eventually fail first when subjected to extreme loads such as blasts. Blast resistant doors in a structure work as effective barriers against blast pressure thus making the entire structure safe. Accordingly, the need to provide blast resistant doors arises in important structures to endure blast pressure. Herein, the comparative performance of a three-hinged five-latched double leaf composite door subjected to blast loading is investigated using finite element analysis software LsDyna. The composite door consists of front and rear steel plates composed of armor steel and three different infill materials, i.e., polyurethane (PU) foam, aluminum syntactic foam with 200 μm cenosphere (Al200), or plain cement concrete (PC) are explored in this investigation. Comparative studies of these composite doors are performed by varying the thicknesses and types of infill material and blast-scaled distances. The peak deflection, permanent deflection, internal energy, and total energy are compared among the doors considered herein. Weight and cost analysis of the door are also considered to determine the most cost-effective solution. The numerical results show that the polyurethane core door illustrates better performance for 150 mm of core material. However, the plain concrete infill door and cenosphere aluminum alloy core door demonstrate enhanced performance for 100 mm core thickness at 0.15, 0.2, 0.3, and 0.4 m/kg1/3 scaled distances.

Towards a Better Understanding of the Interaction of Fe66Cr10Nb5B19 Metallic Glass with Aluminum: Growth of Intermetallics and Formation of Kirkendall Porosity during Sintering

Metallic-glass-reinforced metal matrix composites are a novel class of composite materials, in which particles of alloys with an amorphous structure play the role of reinforcement. During the fabrication of these composites, a crystalline metal is in contact with a multicomponent alloy of an amorphous structure. In the present work, the morphological features of the reaction products formed upon the interaction of Fe66Cr10Nb5B19 metallic glass particles with aluminum were studied. The composites were processed via spark plasma sintering (SPS), hot pressing or a combination of SPS and furnace annealing. The reaction products in composites with different concentrations of the metallic glass and different transformation degrees were examined. The products of the interaction of the Fe66Cr10Nb5B19 metallic glass with Al were observed as dense layers covering the residual alloy cores, needles of FeAl3 protruding from the dense shells as well as needles and platelets of FeAl3 distributed in the residual Al matrix. The possible role of the liquid phase in the structure formation of the reaction products is discussed. The formation of needle- and platelet-shaped particles presumably occurred via crystallization from the Al-Fe-based melt, which formed locally due to the occurrence of the exothermic reactions between aluminum and iron. At the same time, aluminum atoms diffused into the solid Fe-based alloy particles, forming an intermetallic layer, which could grow until the alloy was fully transformed. When aluminum melted throughout the volume of the composite during heating of the sample above 660 °C, a similar microstructure developed. In both Al–Fe66Cr10Nb5B19 and Al–Fe systems, upon the reactive transformation, pores persistently formed in locations occupied by aluminum owing to the occurrence of the Kirkendall effect.

The Influence of the Manufacturing Process on the Average Grain Size Behaviour of the 6063-Aluminum Core Alloy Clad With 4004 Alloy, O Temper

The Influence of the Manufacturing Process on the Average Grain Size Behaviour of the 6063-Aluminum Core Alloy Clad With 4004 Alloy, O Temper

Core@shell structured NiCo@NiCoP nanorods vertically aligned on Ni foam as an efficient bifunctional electrocatalyst for overall water electrolysis

The development of efficient noble metal-free electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for practical applications in electrochemical water splitting. In this study, core@shell structured nickel cobalt alloy-nickel cobalt phosphide (NiCo@NiCoP) nanorods directly grown on nickel foam (NF) are successfully synthesized throughout hydrothermal, thermal reduction, anodic oxidation, and phosphidation process. The NiCoP shell contributes to excellent redox performance in the electrochemical reaction, while the NiCo alloy core functions as an electron highway, enhancing the electrical conductivity and charge transfer efficiency. The synthesized NiCo@NiCoP/NF exhibits outstanding HER activity with a low overpotentials of 130 mV at a current density of − 100 mA cm−2 and a small Tafel slope of 36 mV dec−1. Additionally, the overpotential required to acquire a current density of 100 mA cm−2 and the Tafel slope is found to be 340 mV and 79 mV dec−1, respectively, for OER. Furthermore, a symmetric water electrolyzer using NiCo@NiCoP/NF as a bifunctional electrocatalyst requires a cell voltage of only 1.55 V to deliver a current density of 10 mA cm−2 and displays remarkable electrochemical durability of over 100 h. The facile synthetic procedure and excellent bifunctional electrocatalytic performance for both HER and OER would provide the great potential for practical application of water electrolysis and future energy conversion and storage technologies.

Gradient multi-layered aluminum sheet with excellent corrosion resistance

Diffusion is a very important phenomenon in the thermal processing, including Cu diffusion, Si diffusion and Zn diffusion in the sheet during brazing. Specifically, the migration of Si affects the amount of liquid metal that can be used to form joint, and further affects the solubility of solid substrate at the liquid–solid interface between the clad alloy and core alloy. In addition, Cu accumulates on Al(Fe,Mn)Si precipitates and in Al–Si eutectic at the grain boundaries. Compared with Al matrix, the formation of Al(Fe,Mn,Cu)Si enhances the potential difference between these materials. These events greatly damaged the corrosion resistance of the sheets. Due to the existence of the interlayer, Zn in the interlayer diffuses to the core layer, and the concentration of dissolved zinc decreases with the increase of depth, resulting in an increasing potential of the Al matrix towards the core layer. With depth from the surface to the core layer, the Al matrix is more cathodic, which promoting lateral corrosion within the interlayer region, prevents through failure and which protects the core alloy. Diffusion during brazing leads to microstructure evolution and local electrochemical characteristics of different layers. The optimized potential gradient of the clad layer-interlayer-core layer can greatly improve the corrosion resistance of the alloy.

Thermally Stable AgPd@ZnO Bimetallic Alloy Nanoparticles for Ethanol Sensors with Long-Term Stability

Bimetallic alloy nanoparticles (NPs) typically provide some unique properties in gas sensing due to the synergistic effects that arise from the two distinct metals, especially selective catalytic oxidation of hazardous volatile organic compounds. However, their practical uses are being held back by the high catalyst cost and the deterioration of catalytic capabilities at elevated temperatures. In this work, extremely thermally stable ZnO-supported AgPd bimetallic alloy core–shell NPs were synthesized, demonstrating resistance to surface oxidation due to the synergistic effect of Ag and Pd atoms. The AgPdalloy@ZnO core–shell NPs outperform the pristine ZnO and Pd@ZnO NPs in ethanol sensing, with a response of 704.08 to 100 ppm ethanol at 300 °C. Besides, the sensor demonstrates excellent selectivity, anti-interfering response, repeatability, long-term stability, and humidity effect. The lattice mismatch, upshifts in the d-band center, and oxidation resistance behavior of AgPdalloy ameliorate their electronic structure, which enhances the catalytic properties and the gas sensing performances in AgPdalloy@ZnO NPs. Most importantly, compared to other noble metal NPs, Ag is very inexpensive and cost-effective, which is a great advantage from an economic perspective.

Ultra high response for hydrogen gas on Pd–Augr-alloy@ZnO core-shell nanoparticles with Pd–Au gradient composition alloy core

Pd@ZnO core-shell nanoparticles (CS-NPs) have shown relatively low response and selectivity to hydrogen gas due to surface oxidation of the Pd core. To overcome this, Pd@Au@ZnO core-double shell nanoparticles (CDS-NPs) with an added Au shell layer between the Pd core and ZnO shell are fabricated via a two steps hydrothermal route. Each as-prepared Pd@Au@ZnO CDS-NP is composed of a cubic Pd core (particle size of about 13 nm), an inner Au shell layer (approximately 5 nm thick) and an outer ZnO shell layer (approximately 45 nm thick). After calcination at 500 °C, each Pd@Au CS-NP core becomes a gradient composition Pd–Au alloy NP, in which the inner is a Pd-rich alloy and the outer is an Au-rich alloy (that retains the core-shell structure). At an optimal working temperature of 300 °C, the Pd-Augr-alloy@ZnO sensor shows a high response (174) toward 100 ppm H2 gas, which is about 3 and 13 times higher than that demonstrated by Pd@ZnO and pure ZnO sensors, respectively. Moreover, the Pd–Augr-alloy@ZnO CS-NPs sensor presents with higher selectivity to hydrogen gas than to other gases. The excellent response and selectivity are the result of a synergistic effect between the catalytic and hydrogen adsorption properties of the gradient composition Pd–Au alloy core.

The Influence of Material Configuration of Fibre-Metal Laminates with Alumina Core on Flexural Strength

Abstract Fibre metal laminates (FMLs) consisting of layers made of PA6 polyamide prepregs reinforced with glass and carbon fibres and an aluminium alloy core are the new variant of the other types used by aerospace FML materials such as GLARE or CARALL. By using a thermoplastic matrix, they can be shaped by stamping processes, which allows for a more efficient production process than classical laminating methods such as vacuum bagging. In addition to the improved impact energy absorption efficiency, the metallic core can be utilised to effectively bond the composite part to adjacent metallic structures. This article presents the influence of the material configuration of fibre-metal laminates consisting of continuous fibre-reinforced thermoplastic outer layers integrated with a layer of metallic aluminium alloy inserts—a number of layers, type and direction of reinforcing fibres—on the static and fatigue flexural properties. In this study, eight laminate configurations were prepared using a one-step variothermal consolidation process. The results showed that in the three-point flexural fatigue test, the samples exceeded 106 cycles at stresses <30% of the static bending strength. Laminates with predominantly longitudinally reinforced layers showed the highest fatigue strength among the FML samples analysed. The type of reinforcing fibres and the number of layers were less affected on the analysed mechanical properties.

Experimental and Numerical Analysis of Chlorinated Polyethylene Honeycomb Mechanical Performance as Opposed to an Aluminum Alloy Design.

Manufacturing aircraft components through 3D printing has become a widespread concept with proven applicability for serial production of certain structural parts. The main objective of the research study is to determine whether a chlorinated polyethylene material reinforced with milled carbon fibers has the potential of replacing the current 5052 NIDA aluminum alloy core of the IAR330 helicopter tail rotor blade, under the form of a honeycomb structure with hexagonal cells. Achieving this purpose implied determining the tensile and compression mechanical properties of the material realized by fused deposition modeling. The tensile tests have been conducted on specimens manufactured on three printing directions, so that the orthotropic nature of the material may be taken into account. The bare compression tests were realized on specimens manufactured from both materials, with similar honeycomb characteristics. All the mechanical tests have been performed on the Instron 8872 servo hydraulic testing system and the results have been evaluated with the Dantec Q400 Digital Image Correlation system. The experimental tests have been reproduced as finite element analyses which have been validated by results comparison, in order to determine if the compression model is viable for more complex numerical analysis.

Equivalent circuits of FeCoZr-alloy nanoparticles deposited into Al2O3 and PZT dielectric matrices nanogranular composite films

The paper presents equivalent substitution circuits (ESCs) describing nanogranular composite films (Fe0.45Cо0.45Zr0.10)x(Al2O3)1 – x and (Fe0.45Cо0.45Zr0.10)x(PZT)1 – x with a concentration of metal-containing granules in the range 0.3 < х < 0.8. Films of 2–7 μm thick were obtained by ion-beam sputtering of composite targets in pure argon or in Ar – O2 mixture, followed by stepwise (with a step of 25 K) isochronous (15 min) annealing in air in the temperature range of 398 – 873 K. Deposition of nanocomposites in an oxygen-containing atmosphere or subsequent annealing in air led to the formation of nanoparticles with a core – shell structure consisting of Fe0.45Cо0.45Zr0.10 metallic alloy cores coated with shells of native iron and cobalt oxides (FeO, Fe3O4, Fe2O3, CoO). It has been established that when such shells contain semiconductor-type iron oxides (like FeO and Fe3O4) the frequency dependences of the total impedance Z (f, T) of nanocomposites can be described using ESCs containing two resonant RCL-circuits, that is accompanied by a positive phase shift of the current relative to the applied bias voltage (the so-called negative capacitance effect). The prevailing of dielectric-like oxides (Fe2O3) in shells around metallic cores leads to ESCs either with one resonant RCL-circuit or without it at all. This results in disappearing of the negative capacitance effect when usual capacitive-like behaviour of nanocomposite behaviour is observed. It is shown that if we construct ESCs for nanocomposites with different ratios of the metallic (FeCoZr) and dielectric (Al2O3, PZT) components, it is possible to describe the Z (f, T) dependences for every circuit elements (R, C, L) corresponding both to individual phase components in nanocomposites including intrinsic semiconductor- or dielectric-like iron and cobalt oxides in shells around metallic cores.

Bimetallic Au-Cu gradient alloy for electrochemical CO2 reduction into C2H4 at low overpotential

Electrocatalytic reduction of CO2 (CO2RR) represents a promising approach to reduce CO2 emission and generate value-added chemicals. Herein, we developed bimetallic Au-Cu gradient alloy nanostructures (AuCu-g) comprising of ultrathin Cu-rich alloy surface and Au-rich alloy core as electrocatalyst via a facial solvothermal method. Impressively, the AuCu-g can stably generate a considerable amount of C2H4 with faradaic efficiency (FE) ∼20 % at a low limiting potential of −0.4 V versus reversible hydrogen electrode (RHE) due to its unique gradient structure and multi-component tandem effect. The potential-dependent in situ Raman spectrum indicated an enhanced *CO adsorption strength and a remarkable CO intermediate generation over Au-Cu gradient alloy at low overpotentials during CO2 reduction process. This work shines a light for developing mutilmetallics toward efficient CO2 RR.

Highly Durable Pt-Based Core-Shell Catalysts with Metallic and Oxidized Cobalt Species for Boosting the Oxygen Reduction Reaction

A self-supported Pt-CoO alloy catalyst has recently been reported as a new concept for Pt-based catalysts combining high surface area with high ORR activity. [1] Very recently, the presence of cobalt oxide species within Pt-Co catalyst after electrochemical dealloying in acidic media has also been reported by Weber et al. [2] However, the elemental distribution particularly for light elements like oxygen as well as the influence of the Co oxide on the ORR activity are still unclear to date.We prepared a disordered PtCoOx alloy catalyst using wet-impregnation - freeze-drying - thermal annealing method. [3] After electrochemical activation by dealloying, the less noble metal is dissolved from the nanoparticle surface and the remaining Pt surface atoms are forming a protective particle shell referred to as core-shell catalyst. [2, 3] Using high resolution scanning transmission electron microscopy in combination with electron energy loss spectroscopy (STEM-EELS) we were able to explore the detailed structure of the activated PtCoOx catalyst with a Pt-enriched shell. Based on the EELS elemental maps of Pt, Co and O, we observed that oxygen is mainly located at the interface between the Pt-enriched shell and the PtCoOx alloy core. Thus, the CoOx species are highly stable during the electrochemical dealloying in acidic media. The ORR mass activity (0.56 ± 0.14 A mgPt -1 at 0.9 VRHE) of the PtCoOx core-shell catalyst is 2.5-times higher, whereas the ORR specific activity (592 ± 171 µA cmPt -2 at 0.9 VRHE) is 3-times higher than that for commercial Pt/C (0.24 ± 0.05 A mgPt -1, 187 ± 29 µA cmPt -2). The stability of the CoOx species and the electrochemical catalyst durability were tested by using an accelerated stress test (AST, 10,000 cycles from 0.5 to 1.0 VRHE) in acidic media. Here, the PtCoOx core-shell catalyst showed an improved electrochemical durability compared to Pt/C and maintains 85% of the initial ECSA, 54% of the initial ORR mass activity and 68% of the initial ORR specific activity, respectively. From the STEM-EELS and XPS measurements, we revealed an increase of the thickness of the Pt-enriched shell of several monolayers after the AST protocol. Very surprisingly, the cobalt oxide in the sub-surface layers still remains, but it is less narrowly distributed than before the AST experiment.Thus, we suggest that the Co oxide species in PtCoOx alloy catalyst might have a positive effect on the ORR performance and durability and could even be a yet undiscovered alternative to metallic cobalt.Reference:[1] G.W. Sievers et al., Nat. Mater., 2021, 20, 208-213;[2] D.J. Weber et al., J. Mater. Chem. A, 2021, 9, 15415-15431;[3] M. Oezaslan et al., J. Electrochem. Soc., 2012, 159, B394-B405.

Metallurgical Characterization of a Copper-Alloy Aramaic-Inscribed Object from Tulûl Mas‘ud (Elyakhin)

An Aramaic-inscribed object made of copper-alloy was discovered in 1993 in the south-western part of Tulûl Mas‘ud (Moshav Elyakhin) and has recently been studied using an archaeometallurgical approach. Based on visual testing and multifocal light microscopy observation, the object was probably produced in a nearby workshop, with the inscription engraved using a sharp tool during the production process. Given the larger assemblage of inscribed copper-alloy artefacts from the site, this item appears not only to have been used as a cultic object, but was also most probably made for the purpose of cultic offerings. The XRF analysis results of the Aramaic-inscribed object after it was sanded revealed the core metal to have been made of relatively pure copper with a tin content of less than 1.0 wt. % Sn. The choice to produce the object using a low-tin copper-alloy indicates that the alloy was chosen based on technological considerations, in order to facilitate plasticity in fashioning the part into its cylindrical shape. The manufacturing process involved bending the object while it was hot and shaping it into its final form by means of several cycles of forging and annealing. Although the current research has revealed the bulk composition and the general manufacturing process of the object, the microstructure of the core alloy could not be observed because destructive testing was not permitted. Although only a single copper object was analysed, the current archaeometallurgical study allows to gain further information on metallurgical knowledge and manufacturing processes of copper objects in the Persian period Levant.