Carbide Interface Research Articles

Effect of tungsten carbide interface decoration on thermal and mechanical properties of carbon fiber reinforced copper matrix composites

The use of carbon fiber (CF)/copper (Cu) composites as thermal management materials shows significant promise. However, inadequate interface bonding hinders their thermal properties. This study introduces a novel method to create tungsten carbide–coated CFs (CF(WC)) using the molten salt method. These coated fibers are then used to develop a CF(WC)/Cu composite through vacuum hot-pressing sintering. Results reveal that the WC coating, formed at 1100 ℃ for 60min with a tungsten trioxide/CF molar ratio of 1/10, is continuous, crack-free, and has an appropriate thickness. The WC coating facilitates excellent interface bonding between Cu and CF, thus effectively improving the initial poor interface bonding. With similar 50% fiber content, the CF(WC)/Cu composite exhibits better thermal and mechanical properties than the CF/Cu composite. The in-plane direction thermal conductivity and bending strength of the CF(WC)/Cu composite are 398.7 ± 8.1Wm−1 K−1 and 195.3 ± 6.2MPa, which are 35.3% and 90.4% higher, respectively, than those of the CF/Cu composite. Additionally, the in-plane direction coefficient of thermal expansion is 6.5 ± 0.3 × 10−6 K−1, representing a notable reduction of 37.5%. These exceptional properties, coupled with the simplicity and efficacy of the preparation process, offer valuable insights for the advancement of carbon/Cu thermal management materials.

Silicon‐On‐Silicon Carbide Platform for Integrated Photonics

AbstractSilicon carbide (SiC)'s nonlinear optical properties and applications to quantum information have recently brought attention to its potential as an integrated photonics platform. However, despite its many excellent material properties, such as large thermal conductivity, wide transparency window, and strong optical nonlinearities, it is generally a difficult material for microfabrication. Here, it is shown that directly bonded silicon‐on‐silicon carbide can be a high‐performing hybrid photonics platform that does not require the need to form SiC membranes or directly pattern in SiC. The optimized bonding method yields defect‐free, uniform films with minimal oxide at the silicon–silicon–carbide interface. Ring resonators are patterned into the silicon layer with standard, complimentary metal–oxide–semiconductor (CMOS) compatible (Si) fabrication and measure room‐temperature, near‐infrared quality factors exceeding 105. The corresponding propagation loss is 5.7 dB cm−1. The process offers a wafer‐scalable pathway to the integration of SiC photonics into CMOS devices.

Effects of different element coatings on the interface characteristics and thermal conductivity of vacuum-sintered diamond/Cu composites

The interface structure holds paramount significance in enhancing the thermal conductivity (TC) of diamond/Cu composites, positioning them as a promising candidate for thermal management applications. Diamond/Cu composites (55% volume fraction) with three distinct interfacial carbides were fabricated via sintering at 950 °C using Cu and diamond powder coated with Ti, Cr, and W. During the sintering process, interfacial layers of TiC, Cr3C2, and W2C carbides formed at the composite interfaces. The findings reveal that the interfacial bonding strength among these three composites adheres to the following hierarchy: Ti-D/Cu exceeds Cr-D/Cu, which surpasses W-D/Cu. This hierarchy stems from the varying degrees of carbide coating integrity attained at 950 °C. Furthermore, the coating morphology differs on the diamond-{100} and -{111} crystal planes. Notably, among the interfacial carbides, TiC coating exhibits the most compact and contiguous structure postsintering. Consequently, Ti-D/Cu composites boast the highest density, reaching 95.49%, along with a remarkable TC of 317.66 W/mK. A comparative analysis of the fracture morphology of these composites reveals that Ti-D/Cu, characterized by the most robust interfacial bonding, exhibits a intransgranular fracture mechanism. This study offers profound insights and theoretical implications for the interface design of diamond/Cu composites, paving the way for their effective utilization in heat dissipation materials.

Nanocarbon architecture-intervened interface design of Cu matrix composites towards necking-delayed fracture and toughening

In-situ formed interfacial carbides always sacrifice the structure integrity of reinforcement in nanocarbon/metal composites. Herein, leaf-like carbon nanotube-graphene nanoribbon (CNT-GNR) hybrids, consisting of CNT midrib and GNR margin, was synthetized to solve the above dilemma in nanocarbon-CuCr system. Results demonstrate that high-density nano-sized Cr7C3, which had specific orientation relationship related to the CuCr matrix ([0 0 1]Cr7C3//[011]CuCr, (2‾ 20) Cr7C3//(11 1‾)CuCr), was in-situ formed at GNR-Cu interface via “heterogeneous nucleation-growth” pattern. Meanwhile, the integrity of CNT midrib was well-retained. In-situ SEM tensile results show that such designed interface effectively prevents crack propagation, makes crack blunt via coordinated plastic deformation of local matrix, and guarantees the failure of CNT-GNR by breakage mode, being crucial for exerting the toughening and promoting strength-ductility synergy of CNT-GNR/CuCr.

Temperature-Induced Interface Hybridization of WC Boosts NiCu Activity for Alkaline Hydrogen Oxidation Reaction.

The development of non-precious hydrogen oxidation reaction (HOR) catalysts is a major challenge for the commercialization of Pt-free fuel cells. Herein, a temperature-induced phase hybridization method is reported that greatly improves the catalytic performance of NiCu alloy for the HOR. The migration of W atoms hybridizes the interface of tungsten oxide (WOx) and tungsten carbide (WC) at the onset reduction temperature of WOx, leading to a greatly weakened H binding energy and an optimized OH binding energy, which endows NiCuW/WOx-WC@WC with favorable stability and CO resistance during HOR. The hybridization catalysts deliver a high mass activity of 29.37 mA mg-1 Ni and reach a peak power of 298 mW.cm-2 in H2-O2 anion exchange membrane fuel cells (AEMFCs).

First Principle Study on Schottky Barrier at Ni/Graphene/4H-SiC Interface

High stability 4H-SiC ohmic contact is currently a key technical challenge that silicon carbide devices urgently need to overcome. It is important to reduce the Schottky barrier height (SBH) at the Ni/4H-SiC interface to optimize ohmic contact. In this paper, the mechanisms of graphene layer changing Ni/4H-SiC interface Schottky barrier height (SBH) are studied based on the first-principles method within the local density approximation. Theoretical studies have shown that graphene intercalation can reduce the SBH of Ni and 4H-SiC interfaces. The reason of SBH reduction may be that the graphene C atoms saturate the dangling bonds on the 4H-SiC surface and the influence of the metal-induced energy gap state at the interface is reduced. In addition, the new phase formed at the interface of graphene and silicon carbide has a lower work function. Furthermore, an interfacial electric dipole layer may be formed at the 4H-SiC/graphene interface which may also reduce the SBH. These results make them to be promising candidates for future radiation resistant electronics.

Quasi-freestanding AA-stacked bilayer graphene induced by calcium intercalation of the graphene-silicon carbide interface

We study quasi-freestanding bilayer graphene on silicon carbide intercalated by calcium. The intercalation, and subsequent changes to the system, were investigated by low-energy electron diffraction, angle-resolved photoemission spectroscopy (ARPES) and density-functional theory (DFT). Calcium is found to intercalate only at the graphene-SiC interface, completely displacing the hydrogen terminating SiC. As a consequence, the system becomes highly n-doped. Comparison to DFT calculations shows that the band dispersion, as determined by ARPES, deviates from the band structure expected for Bernal-stacked bilayer graphene. Instead, the electronic structure closely matches AA-stacked bilayer graphene on calcium-terminated SiC, indicating a spontaneous transition from AB- to AA-stacked bilayer graphene following calcium intercalation of the underlying graphene-SiC interface.

Atomic-scale manipulation of buried graphene–silicon carbide interface by local electric field

Precision of scanning tunneling microscopy (STM) enables control of matter at scales of single atoms. However, transition from atomic-scale manipulation strategies to practical devices encounters fundamental problems in protection of the designer structures formed atop the surface. In this context, STM manipulation of subsurface structures on technologically relevant materials is encouraging. Here, we propose a material platform and protocols for precise manipulation of a buried graphene interface. We show that an electric field from the STM tip reversibly controls breaking and restoring of covalent bonds between the graphene buffer layer and the SiC substrate. The process involves charge redistribution at the atomically sharp interface plane under the epitaxial graphene layer(s). This buried manipulation platform is laterally defined by unit cells from the corresponding (6×6)SiC moiré lattice of the epitaxial graphene. Local and reversible electric-field-induced patterning of graphene heterostructures from the bottom interface creates an alternative architecture concept for their applications.

A low-temperature strategy to rapidly prepare high-quality diffusion-bonded joint of dissimilar superalloys enabled by pulsed current

Joining of dissimilar superalloys is indispensable in the field of advanced manufacture, achieving a high-quality joint while minimizing thermal damage to substrates during diffusion bonding is a critical but challenging pursuit. A low-temperature and rapid diffusion bonding strategy enabled by pulsed current was proposed to resolve this challenge. Attributed to the enhanced interfacial plastic-deformation and carbide-precipitation, pulsed current rapidly achieved a nanovoid-free and tight joint of GH3536 and GH5188 superalloys at a low temperature of 850 °C for 5 min. Meanwhile, the rapid joining process prevented the interfacial carbides from coarsening and allowed their elimination in a short-term heat-treatment. The carbide dissolution, recrystallization of highly-deformed grain and cross-interface grain growth during heat-treatment significantly enhanced the joint performance, the heat-treated joint exhibited a high ultimate strain of 25.5 % and a tensile strength comparable to the raw GH3536.

Microstructural effects on impact-sliding wear mechanisms in D2 steels: The roles of matrix hardness and carbide characteristics

This study investigates the wear micromechanisms of D2 steels under impact-sliding conditions, offering insights into their performance when used in applications such as trimming dies for high-strength steel sheets where they undergo plastic deformation and chipping. Two D2 steel samples, both with a bulk hardness of 59.7 HRC but different matrix hardnesses and carbide distributions, are tested by using an impact-sliding wear test rig at Hertzian contact pressures exceeding 2 GPa. The sample with a softer matrix exhibits wear primarily through delamination caused by plastic deformation. This initiates cracks at the matrix/primary carbide interface, leading to material loss in the form of large chips. In contrast, the steel with a harder matrix shows reduced wear due to its resistance to plastic deformation. Initially, wear occurs through the fracture of primary carbides. However, with prolonged loading, the matrix begins to soften, adopting a wear mechanism similar to the D2 steel with softer matrix. Notably, smaller primary carbides are associated with improved wear resistance by limiting the initiation sites for cracks, especially at the matrix/primary carbide interface. This understanding enables the selection and design of heat treatments to optimize D2 steel microstructure, thus improving resistance to impact-sliding wear damages observed in processes like trimming.

Unveiling the failure mechanism on creep response of a casting Ni-based superalloy in thin-wall thickness

With the improvement of thermal efficiency and the lightweight tendency of engine blades, Ni-based superalloy is widely used owing to its excellent performance in high-temperature atmospheres. This work studied the effects of surface oxidation, internal environmental attack, and matrix damage on the failure mechanism in a thin-walled casting Ni-based superalloy at 980 °C/160 Mpa. At the edge of the fracture, the sample suffered a severe environmental attack, resulting in the oxidation-affected zone forms. However, the loss of effective bear area induced by surface damage could not be the main reason for the sample's failure. At the interior of the matrix, voids were preferably initiated at the interface of MC carbides. As the increase of creep deformation, dynamic recrystallization (DRX) occurred at the tip of the voids, which increased the transverse grain boundaries and promoted crack propagation. Moreover, the DRX provided a short penetration path for the nitrogen, causing internal nitridation with AlN and Ti(Ta)N to precipitate. EBSD analysis confirmed that nitrides induced significant dislocations to accumulate at the boundaries of nitrides/γ, accelerating the failure of the sample.

Impact of the oxidation temperature on the density of single-photon sources formed at SiO2/SiC interface

The impact of oxidation temperature on the formation of single photon-emitting defects located at the silicon dioxide (SiO2)/silicon carbide (SiC) interface was investigated. Thermal oxidation was performed in the temperature range between 900 and 1300 °C. After oxidation, two different cooling processes—cooling down in N2 or O2 ambient—were adopted. Single photon emission was confirmed with second-order correlation function measurements. For the samples cooled in an N2 ambient, the density of interface single photon sources (SPSs) increased with decreasing oxidation temperature with a density that could be controlled over the 105 to 108 cm−2 range. For the O2 cooled samples, on the other hand, many interface SPSs were formed irrespective of the oxidation temperature. This is attributed to the low-temperature oxidation during the cooling process after oxidation.

Investigating microstructural features of the carbon nanotube-aluminum hybrid active plate on diffusion induced stresses in the bilayer electrode with initial stretching

Various types of batteries are produced to support years of service for implantable medical devices. Evaluation of internal stresses in nanoparticle-contained electrodes for lithium-ion batteries (LIBs) is a fundamental step toward enhancing their durability. In this research, diffusion induced stresses (DISs) in the bilayer electrode consisted of the carbon nanotube (CNT)-aluminum (Al) nanocomposite active plate bonded to the current collector are investigated. Modeling the DIS is performed by applying the initial stretching on the CNT-Al active plate. Effective properties of CNT-filled Al nanocomposites are calculated using micromechanics models in which the formation of interfacial carbide between the Al and CNT is considered. The role of important microstructural features including amount, length, diameters, curved structure and dispersion type of CNTs, and the thickness and property of interphase in DISs is examined to provide design insights for LIB electrodes. The blending of straight CNTs with a high aspect ratio significantly reduces the tensile stress in the current collector, both compressive and tensile stresses in the nanocomposite active plate and especially the stress drop at the collector/plate interface. Moreover, the DISs can be alleviated by the formation of a stiff and thick interphase between the Al and nanotubes. The CNT-contained electrode with a stretched active plate exhibits lower internal stresses.

Carrier Trap Density Reduction at SiO2/4H-Silicon Carbide Interface with Annealing Processes in Phosphoryl Chloride and Nitride Oxide Atmospheres.

The electrical and physical properties of the SiC/SiO2 interfaces are critical for the reliability and performance of SiC-based MOSFETs. Optimizing the oxidation and post-oxidation processes is the most promising method of improving oxide quality, channel mobility, and thus the series resistance of the MOSFET. In this work, we analyze the effects of the POCl3 annealing and NO annealing processes on the electrical properties of metal-oxide-semiconductor (MOS) devices formed on 4H-SiC (0001). It is shown that combined annealing processes can result in both low interface trap density (Dit), which is crucial for oxide application in SiC power electronics, and high dielectric breakdown voltage comparable with those obtained via thermal oxidation in pure O2. Comparative results of non-annealed, NO-annealed, and POCl3-annealed oxide-semiconductor structures are shown. POCl3 annealing reduces the interface state density more effectively than the well-established NO annealing processes. The result of 2 × 1011 cm-2 for the interface trap density was attained for a sequence of the two-step annealing process in POCl3 and next in NO atmospheres. The obtained values Dit are comparable to the best results for the SiO2/4H-SiC structures recognized in the literature, while the dielectric critical field was measured at a level ≥9 MVcm-1 with low leakage currents at high fields. Dielectrics, which were developed in this study, have been used to fabricate the 4H-SiC MOSFET transistors successfully.

Iron carbide interface modulating for synergies of 3D-graphene-like and iron-coated Fe3O4 particles for high microwave absorption performance

Iron carbide interface modulating for synergies of 3D-graphene-like and iron-coated Fe3O4 particles for high microwave absorption performance

Elimination of Carbides in Carburized Layer of Stainless Steel/Carbon Steel by Horizontal Continuous Liquid-Solid Composite Casting.

The carbides in the carburized layer of stainless steel (SS)/carbon steel (CS) clad plates are prone to inducing intergranular cracks and reducing the interfacial bonding strength. In this paper, SS/CS clad plates were fabricated by horizontal continuous liquid-solid composite casting (HCLSCC), and the formation mechanism of the interfacial carbides and their effect on the elimination of carbides in the carburized layer were revealed by numerical simulation and thermodynamic calculations. During the HCLSCC process, the cladding interface encountered re-melting and re-solidification after rapid melting and solidification, resulting in liquid-liquid and solid-solid diffusion at the cladding interface, where the atomic ratio of Cr/C (Cr/C) gradually increased. Therefore, strip M7C3 and M23C6 carbides as well as blocky M23C6 carbides formed at the cladding interface in turn and had a coherent relationship with the matrix. The blocky M23C6 carbides led to an increase of 240% in the interfacial ferrite strength. The formation of interfacial carbides reduced the difference in C activity between the cladding interface and SS, thus preventing the diffusion of C to SS and inhibiting carbide precipitation in the carburized layer of SS, which was beneficial to improving the interfacial bonding strength.

Growth mechanisms of interfacial carbides in solid-state reaction between single-crystal diamond and chromium

Interfacial bonding is one of the most challenging issues in the fabrication, and hence comprehensively influences the properties of diamond-based metal matrix composites (MMCs) materials. In this work, solid-state (S/S) interface reaction between single-crystal synthetic diamond and chromium (Cr) metal was critically examined with special attention given to unveil the role of crystal orientation in the formation and growth of interfacial products. It has been revealed that catalytically converted carbon (CCC) was formed prior to chromium carbides, which is counterintuitive to previous studies. Cr7C3 was the first carbide formed in the S/S interface reaction, aided by the relaxation of diamond lattices that reduces the interfacial mismatch. Interfacial Cr7C3 and Cr3C2 carbides were formed at 600 and 800 °C, respectively, with the growth preferred on diamond (100) plane, because of its higher density of surface defects than (111) plane. Interfacial strain distribution was quasi-quantitively measured using windowed Fourier Transform-Geometric Phase Analysis (WFT-GPA) analysis and an ameliorated strain concentration was found after the ripening of interfacial carbides. Textured morphologies of Cr3C2 grown on diamond (100) and (111) planes were perceived after S/S interface reaction at 1000 °C, which is reported for the first time. The underlying mechanisms of Cr-induced phase transformation on diamond surface, as well as the crystal orientation dependent growth of interfacial carbides were unveiled using the first-principles calculation. The formation and growth mechanisms of Cr3C2 were elucidated using TEM and XRD analyses. Finally, an approach for tailoring the interfacial microstructure between synthetic diamond and bonding metals was proposed.

Investigating the effect of Al, Mo or Mn addition to CoCrFeNi entropy alloys on the interface binding properties of WC/HEA cemented carbides

At present, it is found that the mechanical properties of WC/HEA cemented carbide are mainly affected by the interfacial bonding properties of hard phase and bonding phase. Therefore, the effect of adding Al, Mo or Mn on the interfacial bonding properties of WC/HEA cemented carbides was studied by first-principles simulation. The results show that adding Mn can enhance the interface bonding performance, while adding Al and Mo is the opposite. Compared with Al and Mo atoms, Mn atoms are more likely to form strong bonds with W atoms at WC/HEA cemented carbide interface. In order to verify the rationality of the calculation, WC/HEA cemented carbide samples were prepared by mechanical alloying and gas pressure sintering. It is found that WC/CoCrFeNiMn has the best mechanical properties. Its hardness, fracture toughness and strength are 1562 HV, 9.3 MPa·m1/2, 850 MPa. The experimental results further confirm that adding Mn can improve the interfacial bonding properties of WC/HEA cemented carbide.

The Microzone Structure Regulation of Diamond/Cu-B Composites for High Thermal Conductivity: Combining Experiments and First-Principles Calculations

The interface microzone characteristics determine the thermophysical properties of diamond/Cu composites, while the mechanisms of interface formation and heat transport still need to be revealed. Here, diamond/Cu-B composites with different boron content were prepared by vacuum pressure infiltration. Diamond/Cu-B composites up to 694 W/(mK) were obtained. The interfacial carbides formation process and the enhancement mechanisms of interfacial heat conduction in diamond/Cu-B composites were studied by HRTEM and first-principles calculations. It is demonstrated that boron can diffuse toward the interface region with an energy barrier of 0.87 eV, and these elements are energetically favorable to form the B4C phase. The calculation of the phonon spectrum proves that the B4C phonon spectrum is distributed in the range of the copper and diamond phonon spectrum. The overlapping of phonon spectra and the dentate structure together enhance the interface phononic transport efficiency, thereby improving the interface thermal conductance.

Synergetic effects of Mo2C sphere/SCN nanocatalysts interface for nanomolar detection of uric acid and folic acid in presence of interferences

Till to date, the application of sulfur-doped graphitic carbon nitride supported transition metal carbide interface for electrochemical sensor fabrication was less explored. In this work, we designed a simple synthesis of molybdenum carbide sphere embedded sulfur doped graphitic carbon nitride (Mo2C/SCN) catalyst for the nanomolar electrochemical sensor application. The synthesized Mo2C/SCN nanocatalyst was systematically characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with elemental mapping. The SEM images show that the porous SCN network adhered uniformly on Mo2C, causing a loss of crystallinity in the diffractogram. The corresponding elemental mapping of Mo2C/SCN shows distinct peaks for carbon (41.47%), nitrogen (32.54%), sulfur (1.37%), and molybdenum (24.62%) with no additional impurity peaks, reflecting the successful synthesis. Later, the glassy carbon electrode (GCE) was modified by Mo2C/SCN nanocatalyst for simultaneous sensing of uric acid (UA) and folic acid (FA). The fabricated Mo2C/SCN/GCE is capable of simultaneous and interference free electrochemical detection of UA and FA in a binary mixture. The limit of detection (LOD) calculated at Mo2C/SCN/GCE for UA and FA was 21.5 nM (0.09 – 47.0 μM) and 14.7 nM (0.09 – 167.25 μM) respectively by differential pulse voltammetric (DPV) technique. The presence of interferons has no significant effect on the sensor’s performance, making it suitable for real sample analysis. The present method can be extended to fabricate an electrochemical sensor for various molecules.