Bimetallic Composites Research Articles

Super Bonding Strength of Al2O3 Nanoparticles Reinforced Sn Interlayer Steel/Aluminum Bimetal Casting

For specialized applications, it is incumbent to develop new materials that enable manufacturers to develop new processes and designs. For better fuel economy, structural integrity, and lightweight applications, the development of bimetallic steel/aluminum (Al) alloys having a strong interfacial bond is required. Therefore, a mild steel/Al-bearing alloy bimetallic composite was investigated in this study. Firstly, a tin (Sn) interlayer was developed between the steel substrate and the Al-bearing alloy by the tinning process. For further improvement in the interfacial integrity, alumina (Al2O3) nanoparticles were added to the Sn powder during the tinning process. Four different wt.% of Al2O3 nanoparticles of 0.25, 0.5, 1, and 1.5 were added and mixed thoroughly with Sn powder before mixing them with flux prior to the tinning process. Finally, molten Al-bearing alloy (Al–Sn-Si–Cu) was poured over the Al2O3 nanoparticles reinforced tinned steel substrate. A cross-section of the steel/Al-bearing alloy bimetallic composite was prepared for optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and shear testing. The cross-section microstructure of the steel/Al-bearing alloy bimetallic composite revealed irregular and discontinuous interfacial layers in the case of the low-temperature (170 °C) tinning process. However, a uniform, continuous interfacial layer was fabricated during the tinning process when additional preheat to the steel substrate and tinning process was adopted. It can be reported that low Al2O3 nanoparticles loading (0.25%) and steel substrate preheating were recommended for the better interfacial layer in the steel/Al-bearing alloy bimetallic composite.

A new insight into the mechanism in Fe3O4@CuO/PMS system with low oxidant dosage

Developing efficient catalyst for peroxymonosulfate (PMS) activation is of great importance for the degradation and mineralization of organic pollutants. Herein, magnetic Fe3O4@CuOx was constructed to activate PMS for the removal of triclosan (TCS). Our results demonstrated that introducing Fe3O4 not only promoted the dispersion of CuO but also improved the electron donor capacity of Cu and promoted the redox cycle of Fe, thus enhancing effective activation of PMS. Compared with pure Fe3O4 or CuO, the iron-copper interaction of the bimetallic composites facilitated the production of singlet oxygen (1O2), and thus showed excellent adaptability to various inorganic anions and actual wastewater. Of note, O2 may be involved in the reaction to generate superoxide radical (O2•–), which facilitated TCS removal in case of lower PMS dosage (40 μM). Elevating PMS concentration to 500 μM, a theoretical value for 20 μM TCS mineralization, enabled TCS to be deeply mineralized in ultrapure water (86% removal of total organic carbon (TOC)). Further increasing PMS concentration could achieve satisfactory mineralization in wastewater samples with much higher TOC background values. Overall, this study provides a new insight into the mechanism in Fe3O4@CuO/PMS system with low oxidant dosage, which is beneficial to improve the practical application of SR-AOPs.

Microstructure, Microhardness and Tribological Properties of Bronze-Steel Bimetallic Composite Produced by Vacuum Diffusion Welding.

In this paper, a lead–bronze/steel bimetal composite was produced by vacuum diffusion welding technology. The microstructure, hardness and tribological properties under the dry sliding condition of the bimetal structured material were investigated and compared with two reference samples, i.e., lead–bronze and Mn/Si–brass. The wear mechanism of the three materials was also analyzed in detail. It was found that the bimetallic structure possessed the best wear resistance among the three samples. When paired with the ball bearing steel, the wear rates of the lead–bronze and Mn/Si–brass were 13 and 54 times higher than that of the bimetal composite. When paired with bearing steel, the wear rates of the two materials were 13 and 54 times higher than the bimetallic composite, respectively. This is because the steel layer served as a bearing layer to decrease the plastic deformation of the bronze layer. Furthermore, the lead can accelerate the formation of a dense hardened layer at the sliding interfaces to avoid subsequent wear of the bronze surface. Nevertheless, this hardened layer caused severe scuffing on the steel balls. Therefore, lead–bronze/steel structured material is recommended to match with hard counterface material, such as cemented carbide.

Hollow multi-dimension CoCeS/C as peroxymonosulfate activator toward ofloxacin degradation via coexisting free radical and nonradical pathways

A catalyst with multi-metal introduction and a hollow structure is very promising for peroxymonosulfate (PMS) activation. In this study, Ce doped hollow bimetallic sulfide carbon composite (CoCeS/C) were fabricated from three dimensional layered double hydroxides (LDHs), which was synthesized via metal-organic frameworks (MOFs) self-sacrificial template strategy. The as-synthesised composite was applied to the catalytic degradation of ofloxacin (OFX) and the result indicated that the reaction rate constant (k2) of Ce doped CoCeS/C (18.539 mmol−1·L·min−1) was about 5.7 times higher than CoS/C (3.230 mmol−1·L·min−1) which was without Ce doping. Singlet oxygen (1O2) and SO4-• were verified as the dominant reactive oxygen species (ROS) responsible for OFX via quenching tests and electron paramagnetic resonance spectroscope (EPR). The catalyst kept high removal efficiency over the pH range of 3.0–11.0. In addition, the catalyst still showed good reusability after four runs, as well as strong resistance to versatile inorganic ions and background organic matters in the oxidative treatment of OFX. Finally, degradation pathways were proposed by analyzing the degradation intermediates. These results revealed that the designed CoCeS/C catalyst exhibits wide promising application prospects for the degradation of organic residues in environmental remediation.

Simulation of Hydro-Mechanical Billet Pressing of Fibrous Bimetallic Composites

The simulation of hydro-mechanical billet pressing of bimetallic composite is performed. Using mathematical modeling and simulation exercise, the influence of the main operational parameters, which include: draw-forming, the cone angle of the working die and the conditions of contact friction, on the strain heterogeneity, damage to the fibers (cores), and the extrusion stress, is studied. A method and an expert system were developed that allowed to carry out a computational experiment and a multi-criteria choice of rational values of the technological experiment is carried out. The results of the study are used to improve the industrial production of multi-core bimetallic wires for electrical purposes.

Improvement of the Supercapacitor Performance of Nickel Molybdenum Chalcogenides/Reduced Graphene Oxide Composites through Vanadium-Doping Induced Crystal Strain Relaxation and Band Gap Modification

Metal chalcogenide/reduced graphene oxide (RGO) composites have gained significant interest as promising electrode materials for supercapacitor application. Herein, the effect of different chalcogens (O, S, and Se) on nickel-based bimetallic composites along with the addition of a scanty amount of a heteroatom (V) is investigated. Different sizes and electronegativity of the chalcogens alter the morphology of the composites. However, V doping does not change the morphology but regulates the crystalline strain, band-gap energies, and charge transfer kinetics of the materials. All these factors are very important in controlling the performance of a supercapacitor device. Among all the doped and undoped composites, Se-based electrode materials exhibit the highest supercapacitor properties. In a three-electrode configuration, the V-doped Ni-Mo selenide/RGO (VNMSeR) composite electrode exhibits the highest specific capacitance of ∼610 C g–1 (1220 F g–1) at 2 A g–1 current density with a superior rate capability of ∼73.7%. An asymmetric supercapacitor device has been fabricated using VNMSeR as positive and thermally RGO as negative electrode. The device exhibits a maximum energy density of ∼60.5 Wh kg–1 at a power density of 1.47 kW kg–1 and shows ∼83.4% retention (50.5 Wh kg–1) in energy density when the power density increases by ∼8.25-fold (12.12 kW kg–1).

The Effect of Reinforcement Preheating Temperatures on Tribological Behavior of Advanced Quranic Metal-Matrix Composites (QMMC).

The growing applications of iron/copper bimetallic composites in various industries are increasing. The relationship between the properties of these materials and manufacturing parameters should be well understood. This paper represents an experimental study to evaluate the effect of reinforcement (steel rod) preheating temperature on the mechanical properties (bond strength, microhardness, and wear resistance) of copper matrix composites (QMMC). In preparing the QMMC samples, the melted copper was poured on a steel rod that had been preheated to various temperatures, namely, room temperature, 600 °C, 800 °C, and 1200 °C. Properties of the QMMC (interface microstructure, interfacial bonding strength, microhardness, and wear) were investigated. The experimental results revealed that the best bond between the copper matrix and steel rod formed only in the composites prepared by preheating the steel rods with temperatures lower than the recrystallization temperature of steel (723 °C). This is because the oxide layer and shrinkage voids (due to the difference in shrinkage between the two metals) at the interface hinder atom diffusion and bond formation at higher temperatures. The microhardness test showed that preheating steel rod to 600 °C gives the highest value among all the samples. Furthermore, the QMMC’s wear behavior confirmed that the optimization of preheating temperature is 600 °C.

Highly efficient P uptake by Fe3O4 loaded amorphous Zr-La (carbonate) oxides: Electrostatic attraction, inner-sphere complexation and oxygen vacancies acceleration effect

Bimetallic oxides composites have received an increasing attention as promising adsorbents for aqueous phosphate (P) removal in recent years. In this study, a novel magnetic composite MZLCO was prepared by hybridizing amorphous Zr-La (carbonate) oxides (ZLCO) with nano-Fe3O4 through a one-pot solvothermal method for efficient phosphate adsorption. Our optimum sample of MZLCO-45 exhibited a high Langmuir maximum adsorption capacity of 96.16 mg P/g and performed well even at low phosphate concentration. The phosphate adsorption kinetics by MZLCO-45 fitted well with the pseudo-second-order model, and the adsorption capacity could reach 79% of the ultimate value within the first 60 min. The phosphate adsorption process was highly pH-dependent, and MZLCO-45 performed well over a wide pH range of 2.0-8.0. Moreover, MZLCO-45 showed a strong selectivity to phosphate in the presence of competing ions (Cl−, NO3−, SO42−, HCO3−, Ca2+, and Mg2+) and a good reusability using the eluent of NaOH/NaCl mixture, then 64% adsorption capacity remained after ten recycles. The initial 2.0 mg P/L in municipal wastewater and surface water could be efficiently reduced to below 0.1mg P/L by 0.07 g/L MZLCO-45, and the phosphate removal efficiencies were 95.7% and 96.21%, respectively. Phosphate adsorption mechanisms by MZLCO-45 could be attributed to electrostatic attraction and the inner-sphere complexation via ligand exchange forming Zr/La-O-P, -OH and CO32− groups on MZLCO-45 surface played important roles in the ligand exchange process. The existence of oxygen vacancies could accelerate the phosphate absorption rate of the MZLCO-45 composites.

Mono- and Bimetallic Silver-Containing Nitrogen-Doped Carbon Composites and Their Electrocatalytic Activity

The N-doped metal-carbon composites based on the carbonized melamine-formaldehyde polymer (MFP) with silver, silver-copper, and silver-cobalt particles were synthesized. Mono- and bimetallic silver-containing composites were prepared by the reduction of metal nitrates with hydrazine hydrate in an aqueous ethanol medium in the presence of carbon black particles obtained by the heat treatment of MF-polymer at 500 °C. The structural-phase changes before and after the use of metal-carbon composites as electrocatalysts in the electrohydrogenation of p-nitroaniline (p-NA) were studied by X-ray diffraction analysis. The morpho-logical features of the created MFBC + Ag, MFBC + (Ag+Cu) and MFBC + (Ag+Co) composites were stud-ied by electron microscopy. It was established that the synthesized composites mainly contain crystalline phases of the corresponding reduced metals or their alloys. The monometallic MFBC(1) + Ag(1) composite contains reduced silver crystallites of various shapes and localization on porous MF carbon black particles. Higher electrocatalytic activity of the synthesized Ag-containing composites in the p-NA electrohydro-genation was shown in comparison not only with the electrochemical reduction of p-NA but also with MFBC + (Ag+Cu) composites with electrocatalytic hydrogenation of p-NA on Ag + Cu particles (without MFBC). It was found that the use of the studied MFBC-composites increases the selectivity of the formation of the main hydrogenation product (p-phenylenediamine) and decreases the yields of by-products.

Efficient adsorption of nitrate and phosphate from wastewater by the cost- effective Mg/Ca bimetallic oxide composites functionalized peanut shell

Efficient adsorption of nitrate and phosphate from wastewater by the cost- effective Mg/Ca bimetallic oxide composites functionalized peanut shell

Electrospinning one-dimensional surface-phosphorized CuCo/C nanofibers for enzyme-free glucose sensing

High sensitivity of nonenzymatic glucose detection boosted by unique fibrous carbon supported bimetallic composites and surface phosphorization.

Effect of electro-spark deposited ZA12 interlayer on the microstructure and mechanical property of A356/AZ91D by liquid-solid compound casting

In this paper, to fabricate high strength Al/Mg bimetallic composite without the formation of Al12Mg17 intermetallic compound at the interface, ZA12 deposited A356/AZ91D bimetal was achieved by liquid-solid compound casting. The combination between electro-spark technology and compound casting was realized. The process parameters of electro-spark deposition were optimized by considering the thickness, quality, and efficiency of the coating. The microstructure, phase composition and mechanical properties of A356/AZ91D bimetal without and with ZA12 coating were investigated. From AZ91D to A356, the main phases formed across the interface region are: Mg17(Al, Zn)12 + α-Mg in diffusion layer I, Al5Mg11Zn4 and Mg32(Al, Zn)49 in diffusion layer II, and Al3Mg2 and Mg2Si in diffusion layer III. The microhardness of the interface is obviously higher than that of the substrate on both sides. The average shear strength of ZA12 coated A356/AZ91D bimetal is 69.2 MPa. The interface microstructure evolution mechanism of ZA12 coated A356/AZ91D by liquid-solid compound casting was analyzed. The result is helpful for further development of high strength Al/Mg bimetallic composites.

Construction of MOF-derived plum-like NiCo@C composite with enhanced multi-polarization for high-efficiency microwave absorption

Nowadays, facing the inevitable electromagnetic (EM) pollution caused by many electronic products, it is urgent to develop high-performance microwave absorbing materials. In particular, the bimetallic carbon-based composites derived from MOFs exhibit excellent microwave absorption potential due to their simple preparation, low cost, adjustable morphology and magnetoelectric synergy mechanism. In this work, we successfully prepared plum-like NiCo@C composite by simple solvothermal method and carbonization treatment, which displays strong absorption (-55.4 dB) and wide effective absorption band (EAB, 7.2 GHz) when the loading is 20 wt%. The plum-like structure greatly enriches the non-uniform interface and the structural anisotropy contributes to the dissipation of electromagnetic waves. At the same time, the band hybridization and magnetic coupling of NiCo@C contribute to the coordination of EM characteristics. Overall, this work proves the feasibility of NiCo@C hierarchical composite in the field of microwave absorbing, and provides insight for the development of high-performance absorbers.

Constitutive behavior and fracture of intermetallic compound layer in bimetallic composite materials: Modeling and application to bimetal forming process

This paper presents a novel experimental and computational methodology to characterize the fracture behavior of the intermetallic bonding layer particularly for the bimetallic forming applications. The proposed methodology was applied to Al-Sn bearing alloy/mild steel bimetallic composite. Tensile-shear bimetal samples were fabricated to test the metallurgical bonding layer under shear conditions. Based on the macroscopic behavior, the coupled elasto-plasticity and damage constitutive equations for the bond material were formulated and implemented. The used damage model is written within the framework of the thermodynamic of irreversible processes with the concept of internal state variables and the framework of continuum damage mechanics (CDM). The characterization of the shear fracture behavior of the bond has included FE numerical simulation of tensile-shear tests of the bimetallic composite using ABAQUS/Explicit® FE code with the specially developed VUMAT subroutine. Accordingly, a calibration approach has been proposed to identify the fracture parameters of the bond based on the correspondence between the numerically predicted and experimental global shear force–displacement responses. These parameters have been applied to FE model of the U-bending testing of Al-Sn/mild steel bimetallic composite. A qualitative correspondence between numerically predicted results and U-bending experiment of the bimetal conducted under high-speed camera is deemed extremely satisfactory.

Hybrid ZnSe‐SnSe2 Nanoparticles Embedded in Nitrogen‐Doped Carbon Nanocube Heterostructures with Enhanced and Ultra‐stable Lithium‐Storage Performance

AbstractInvited for this month's cover picture are the groups of Prof. Kwang Ho Kim at the Pusan National University (Korea) and Prof. Jun Kang at the Korea Maritime and Ocean University (Korea). The cover picture shows characteristic microstructure images of novel bimetallic selenide composites embedded in N‐doped carbon nanocubes and their enhanced and ultra‐stable electrochemical performances as lithium‐ion battery anodes. Read the full text of the Article at 10.1002/celc.202100846.

Single source precursor derived ZnO–PbO composite thin films for enhanced photocatalytic activity

Bimetallic oxide composite has emerged as an effective stratagem to enhance the performance of metal oxide photoanodes. ZnO–PbO composite thin films were deposited onto fluorine doped tin oxide (FTO) coated glass substrates from a newly synthesized polymeric Zn–Pb based single source precursor {ZnPb(OAc)(TFA)3(THF)2}nvia aerosol-assisted chemical vapor deposition (AACVD) technique. The precursor was synthesized by the reaction of zinc acetate dihydrate (Zn(CH3CO2)2⋅2H2O), and lead acetate trihydrate (Pb(CH3CO2)2⋅3H2O) in the presence of triflouroacetic acid using THF as a solvent. The prepared complex {ZnPb(OAc)(TFA)3(THF)2}n, was characterized by FTIR, NMR, and single crystal X-ray analysis. The polymeric precursor had melting point of 72 ᴼC and decomposed at 450 ᴼC with 36.6% residue as obtained via thermogravimetry (TG/DTG). X-ray diffraction and energy-dispersive X-ray spectroscopy studies of thin films predicted a prominent growth of ZnO–PbO crystallites onto FTO substrate. FESEM analysis illustrated a homogenous and smooth surface with evenly distributed microspheres. The direct band gap of ZnO–PbO composite, estimated by UV–Vis spectroscopy is 2.40 ​eV that proves the narrowing of band gap in composite form of ZnO with PbO. Photoelectrochemical properties of the as-synthesized ZnO–PbO composite thin films investigated in the presence of 0.5 ​M aqueous NaOH solution shows photocurrent density of 705 ​μA ​cm−2 at an applied potential of +0.8 VSCE. The charge transfer dynamics of thin films were also examined using an electrochemical impedance spectroscopy (EIS) technique.

The role of vibration time in interfacial microstructure and mechanical properties of Al/Mg bimetallic composites produced by a novel compound casting

A simple mechanical vibration was used to enhance interface bonding of the Al/Mg bimetallic composites produced by a novel lost foam compound casting in this study. The effect of vibration time on interfacial microstructure and mechanical properties of the Al/Mg bimetallic composites was investigated. The results show that the vibration time had a significant effect on the interfacial microstructure and mechanical properties of the Al/Mg bimetallic composites. With the increase of the vibration time, the cooling rate during the solidification was increased, and the thickness of intermetallic compounds (IMCs) layer at the interface of the Al/Mg bimetallic composites was decreased. This resulted in the decrease of A3Mg2 and Al12Mg17 brittle phases, and the Mg2Si phase at the interface was refined with a distribution change from agglomeration to dispersion. When the vibration time was 300 s, the vibration fully affected the formation and solidification process of the IMCs layer of the Al/Mg bimetallic composites, and had an obvious effect on the reduction of the brittle phases as well as the improvement of the size and distribution of the Mg2Si phase. As a result, the shear strength of the Al/Mg bimetallic composites was the highest, reaching 47.49 MPa, which was 51% higher than that of the Al/Mg bimetallic composites without vibration.

In-situ grafting of Au and Cu nanoparticles over graphitic carbon nitride sheets and unveiling its superior supercapacitive performance as a hybrid composite electrode material

In this article, a bimetallic hybrid composite of Au and Cu nanoparticles over graphitic carbon nitride has been reported as supercapacitor electrode material. The bimetallic Au-Cu/g-C3N4 hybrid was synthesized using facile one-phase impregnation of Au and Cu nanoparticles in holey g-C3N4 sheets. The as-synthesized materials were systematically characterized to assess structural, morphological, electronic, and thermal properties. The electrochemical tests revealed that the Au-Cu/g-C3N4 hybrid uncovers a superior specific capacitance of 506.25 F/g at 1.25 A/g current density amiable cycle stability with 76.1% capacitance retention at 5 A/g current density after 5000 cycles and excellent rate capability. Our designed asymmetric supercapacitor device based on Au-Cu/g-C3N4 hybrid unveils specific energy of 59.3 Wh/kg at a specific power of 2.49 kW/kg. The substantial enhancement in supercapacitor performance of Au-Cu/g-C3N4 compared to pristine g-C3N4, Au/g-C3N4, and Cu/g-C3N4 is attributed to synergy between Au, Cu nanoparticles, and semiconductor g-C3N4 surface. In hybrid electrode material, the mass ratio of components plays a vital role synergistic supercapacitive effect.

Defect-Engineered NiCo-S Composite as a Bifunctional Electrode for High-Performance Supercapacitor and Electrocatalysis.

Defect engineering is a reasonable solution to improve the surface properties and electronic structure of nanomaterials. However, how to introduce dual defects into nanomaterials by a simple way is still facing challenge. Herein, we propose a facile two-step solvothermal method to introduce Fe dopants and S vacancies into metal-organic framework-derived bimetallic nickel cobalt sulfide composites (NiCo-S). The as-prepared Fe-doped NiCo-S (Fe-NiCo-S) possesses improved charge storage kinetics and activities as electrode material for supercapacitors and the oxygen evolution reaction (OER). The obtained Fe-NiCo-S nanosheet has a high specific capacitance (2779.6 F g-1 at 1 A g-1) and excellent rate performance (1627.2 F g-1 at 10 A g-1). A hybrid supercapacitor device made of Fe-NiCo-S as the positive electrode and reduced graphene oxide (rGO) as the negative electrode presents a high energy density of 56.0 Wh kg-1 at a power density of 847.1 W kg-1 and excellent cycling stability (capacity retention of 96.5% after 10,000 cycles at 10 A g-1). Additionally, the Fe-NiCo-S composite modified by Fe doping and S vacancy has an ultralow oxygen evolution overpotential of 247 mV at 10 mA cm-2. Based on the density functional theory (DFT) calculation, defects cause more electrons to appear near the Fermi level, which is conducive to electron transfer in electrochemical processes. Our work provides a rational strategy for facilely introducing dual defects into metal sulfides and may provide a novel idea to prepare electrode materials for energy storage and energy conversion application.

A freestanding cathode with bimetallic MOF-based composites anchored on N-doped porous carbon nanofibers for lithium-oxygen batteries

Simultaneously achieving both bifunctional catalysts and flexible self-supported electrodes are urgently in demand to satisfy rechargeable lithium-oxygen (Li-O2) batteries, particularly for wearable devices. Herein, we propose a novel strategy embracing electrospinning and hot-pressing to develop Co-based composites embedded in porous nitrogen-rich carbon nanofibers (ZnCo-NC/NCF) as a freestanding cathode for Li-O2 batteries. The fabricated electrode is obtained through pyrolysis of bimetallic (ZnCo) zeolitic imidazolate frameworks/polyacrylonitrile (PAN) nanofibers (BMZIF/PAN). Benefiting from outstanding mechanical strength of electrospun carbon matrix and abundant porosity originated from decomposition of ZIFs as well as fully exposed Co-Nx active sites, the achieved cathode is capable of excellent flexibility, high specific surface area, great conductivity and good catalytic behaviors towards both oxygen reduction/evolution reactions. Consequently, the corresponding Li-O2 batteries exhibit remarkably decreased voltage gap (0.49 V), high specific areal capacity (9.52 mAh cm−2) and long-term cycling capability (around 42 cycles under a curtailing capacity of 0.25 at 0.04 mA cm−2). Besides, the evolution of the morphology and electrochemical impedance spectroscopy at various reaction states are further investigated, which confirms that ZnCo-NC /NCF cathode enables formation and decomposition of lithium peroxide during charge-discharge period.