Conductive Powder Research Articles

Hierarchical hybrid conductive powders derived from Ag-deposited Janus particle/MWCNT nanocomposites for enhanced microwave absorption

Hierarchical hybrid conductive powders derived from Ag-deposited Janus particle/MWCNT nanocomposites for enhanced microwave absorption

Uneven Doping of Metal Powder in Carbon Polymer Composites Affects Electrical Conductivity Properties

This paper compares the electrical conductivity of LLDPE-carbon composite materials, LLDPE-carbon-aluminum composites, and LLDPE-carbon-copper composites. Doping with aluminum (Al) and copper (Cu) metal powders influences electrical conductivity in carbon-based polymer composite materials. Adding metal powders as secondary fillers to a mixture of conductive carbon powders and LLDPE can decrease electrical conductivity. This is due to the agglomeration or clustering of metal powders within the polymer matrix, which disrupts conductive pathways and diminishes the efficiency of electrical charge transfer. The impact of filler type and quantity on electrical conductivity in composite materials was examined, and the findings revealed that factors such as the filler's amount, shape, and dispersal significantly affect the composite's electrical resistance properties. Increasing the amount of metal powder filler raises the composite's viscosity, reducing adhesion between the metal and polymer fillers while promoting metal-to-metal contacts.

Feδ+ diaspora titanium dioxide and graphene: A study of conductive powder materials and coating applications.

Feδ+ diaspora titanium dioxide and graphene: A study of conductive powder materials and coating applications.

Studying Heat-Affected Zone, Surface Roughness and Material Removal Rate in NPMEDM Process for Inconel 718 Using Nano Silicon Carbide Powder

Nano powder mixed electrical discharge machining (NPMEDM) is one of the non-traditional machining processes employed to machine metals, which can be tough to machine using traditional processes. It is accomplished by adding conductive powders to dielectric fluid to enhance the performance of the process. In this paper, several experiments were conducted to enhance the process performance in terms of white layer thickness (WLT), heat affected zone (HAZ), surface roughness (SR), and material removal rate (MRR) of the Inconel 718 alloy, machined using Nano SiC powder added to soybean oil, used as a dielectric fluid. The chosen process variables were discharge current, pulse on time, powder concentration, and magnetic field. Experimental outcomes revealed that adding 2 g/l Nano SiC to soybean oil improved the white layer thickness by about 55.16% compared to 0 g/l and 4 g/l additions, while the thickness of heat affected zone increased. Surface roughness and MRR improved when adding 4 g/l of NanoSic to the dielectric fluid; the improvements were approximately 5.54% and 53.99%, respectively.

Investigation into the deicing efficiency and self-healing capability of asphalt mixtures with aluminum dross powder and steel fiber

In winter, reduced friction between tires and icy roads increases accident risks. This study designs an asphalt mixture incorporating conductive waste materials aluminium dross powder (ADP) and steel fibre (SF) to accelerate ice removal. Under simulated −20 °C conditions, microwave heating is applied for 120 seconds to evaluate deicing efficiency. The results show that higher ADP and SF content increases the average surface temperature (AST) and ice-melting speed (IMS). The highest AST increased by 112.86%, while IMS improved by 73.6% compared to the reference sample. A linear relationship (R 2 = 0.91) is observed between ADP-SF content and microwave heating efficiency. For the Self-healing (SH) effect, an indirect tensile test (IDT) is performed before and after damage. Strength values and moisture susceptibility are also determined. Accordingly, higher ADP and SF content during 60 seconds of microwave heating enhanced healing, but after 120 seconds, increased SF content reduces healing effectiveness.

Multi-Objective Optimization of Powder-Mixed Electro-Discharge Machining of Tool Steel Using Advanced Algorithm

<div>Electrical discharge machining (EDM) technology is one of the unconventional machining processes with an ability to machine intricate geometrics with micro finishing. Powder-mixed EDM (PMEDM) extends the EDM process by adding conductive powder to the dielectric fluid to improve performance. This set of experiments summarizes the effect of brass and copper electrode on HcHcr D2 tool steel in chromium powder-mixed dielectric fluid. Powder concentration (PC), peak current (I), and pulse on-time (T<sub>on</sub>) are considered as variable process parameters. General full factorial design of experiment (DOE) and ANOVA has been used to plan and analyze the experiments where powder concentration is observed as the most significant process parameter. The results also reveal that a brass electrode offers a high material removal rate (MRR). Whereas, the copper electrode has reported noteworthy improvement in surface roughness (Ra). Moreover, teaching–learning-based optimization (TLBO) algorithm has been used to optimize the developed multi-objective function assisted by the regression equations.</div>

Preparation of magnetic‐oriented electronic packaging composite materials with improved thermal conductivity and insulating properties by filling magnetic BN@Fe3O4 core‐shell particles into epoxy

AbstractEpoxy resin (EP), as a resin material with excellent insulation performance, has been widely applied in fields such as electronics, coatings, ships etc. However, epoxy resins generally have poor thermal conductivity, which limits their application in the field of new generation of electronic packaging. To address the key issues mentioned above, the BN@Fe3O4 particles with positive out‐of‐plane thermal conductivity were successfully prepared in this study, having a core‐shell structure with rough surfaces as well. As a thermal conductive powder, the disadvantage of hexagonal boron nitride being easily agglomerated in resin has been improved. By applying an external magnetic field, three‐dimensional thermal conduction pathways were constructed in the matrix. The physical and chemical properties of the BN@Fe3O4 powder and its composite materials were analysed and tested. The experiment indicates that the thermal conductive magnetic powder BN@Fe3O4 had been successfully prepared. When the filling amount of BN@Fe3O4 reached 27.5 vol%, the out‐of‐plane thermal conductivity of the composite material was 1.758 W m−1 K−1, which was 982.12% that of pure EP. At this point, the mechanical behaviour and insulation performance of EP composite materials can be effectively guaranteed at the same order of magnitude as pure EP performance.

Continuous porous aromatic framework membranes with acid-/base-induced reversible isomerization for switchable ion conductivity.

Stimuli-responsive ion conductor materials are highly sought after in the fields of biological systems, clean energy, and smart devices. However, it remains a huge challenge to achieve acid/base switchable ion conductors owing to their stringent requirements of structural responsive behaviors, high stability and porosity. In this study, porous aromatic frameworks (PAFs) are utilized as a favorable platform to successfully design and prepare ion conductive powders and its continuous membranes based on a commercially available pH indicator. Interestingly, these PAFs possessed structural reversibility in response to acidic and alkaline environments, followed by an apparent ion-conducting switch of about 4 orders of magnitude (from 3.36 × 10-7 S cm-1 to 4.59 × 10-3 S cm-1) under the conditions of 25 °C and 98% RH. Moreover, the continuous PAF membrane exhibited an ultrahigh ion conductivity of 7.29 × 10-1 S cm-1 after 1 mol per L NaOH treatment and good acid/base switchable cycle stability. To our knowledge, this is the first report on exploring ion-conductive porous frameworks and continuous membranes that dynamically respond to acid/base chemical stimuli. This work provides a new research strategy for the application of ion conductors as so-called "smart materials" even in extremely harsh chemical environments.

REMELTING FERROCHROME-CRUSHING DUST

This article discusses the practical implications of remelting briquettes from ferrochrome dust after crushing. The formation of corrosion-resistant electrically conductive powder (CRP) and its fractional compositions are described, shedding light on the potential applications of this research. The partially described briquetting method used is explained, along with the equipment in detail, providing valuable insights for future research and industrial applications. A literature review on lignosulfonate-based binders provides a comprehensive understanding of this aspect. The work compares the remelt of briquettes in the base and experimental periods, where in the base period, dust is remelted in bulk (in the initial dusty state) and in the experimental period, in a briquette state. The article also characterizes the weighing of charge materials and their comparison; the tables indicate the electricity costs and electrodes spent on remelting, providing practical data for industrial operations. The chemical compositions of the charge materials for remelting and technical and economic indicators (referred to as TEI from now on) are given in the tables, offering practical guidance for future research and operations. The comparison results with standard melting modes are briefly touched upon, providing a valuable benchmark for the research. In the end, the results and conclusions of the work are written, summarizing the study's practical implications.

A Study on Material Removal Rate in Powder-Mixed Electro-Discharge Machining Utilizing Integrated Experimental and Computational Fluid Dynamics Analysis

Electric discharge machining (EDM) serves as a pivotal technique for the precision machining of materials known for their inherent difficulty in conventional cutting processes. Its capability to fashion blind slots and intricate features in conductive materials, otherwise challenging to fabricate using traditional methods, underscores its significance in modern manufacturing. The effectiveness of Electrical Discharge Machining (EDM) hinges upon a multifaceted interplay of electrical and non-electrical variables, encompassing parameters such as current, voltage, cycle time, and powder concentration. This study delves into the realm of EDM with a specific focus on Powder-Mixed Electro-Discharge Machining (PMEDM), aiming to comprehensively explore and optimize the material removal rate (MRR). The experimental investigation, conducted with and without the incorporation of conductive powder particles into the dielectric medium, scrutinizes the impact on MRR, thereby shedding light on the efficacy of powder integration in enhancing machining efficiency. Furthermore, the study ventures into the realm of computational fluid dynamics (CFD) to simulate and analyze the intricate dynamics of dielectric flow, powder particle behavior, and debris movement within the inter-electrode gap (IEG). These simulations serve as invaluable tools in elucidating the underlying mechanisms governing the machining process, providing insights into the intricate interplay between electrical discharges, fluid flow, and particulate dynamics. The synthesis of experimental data and simulation results reveals a strong correlation between the inclusion of powder particles in the dielectric medium and the enhancement of machining efficiency, particularly evident in the observed improvements in MRR. The consistency between experimental findings and simulation outcomes underscores the validity and robustness of the study's methodologies and conclusions. In essence, this research not only contributes to the advancement of understanding of PMEDM but also underscores the potential of integrated experimental and computational approaches in optimizing machining processes. By elucidating the intricate dynamics of powder-mixed EDM and its implications on material removal efficiency, this study paves the way for enhanced precision machining in various industrial applications.

A Comparative Investigation on Powder Mixed EDM Machining of Steel Alloys with Multi-Objective Optimization Using Fuzzy-TOPSIS Method

The current work offers a comparative study that examined the effects of various process parameters, such as dielectric fluid, current (IP), pulse on time (TON), and different conductive powder particles mixed dielectric fluids, on electrical discharge machining (EDM) of AISI 1040, EN31, and HCHCr steels, respectively. The findings indicate that adding conductive particles to the dielectric medium during the powder-mixed EDM (PMEDM) process enhances energy distribution across the spark gap, thereby improving material removal capacity and the surface characteristics of the machined surfaces. Experimental results show that the concentration of powder particles has the most significant impact on surface roughness (Ra) and tool wear rate (TWR), while the most critical factor affecting the material removal rate (MRR) is the current (IP). Additionally, increasing the IP and TON leads to the formation of continuous, thick cracks and a thin white coating on the EDMed surface, as evidenced by scanning electron microscopy (SEM) images of the surface morphology. The study also employs a multi-optimization technique using the Fuzzy-based TOPSIS method to investigate the cumulative effects of the control parameters on performance indicators, namely Ra, MRR, and TWR. In experimental run 8 i.e. moderate IP (5 A), higher TON (180 µs), and higher concentration of copper powder (10 g/l) mixed in EDM oil while machining of AISI 1040, the optimal results i.e. Ra is 5.983 µm, MRR is 27.243 mm3/min, and TWR is 0.775 mm3/min were obtained, respectively.

(Invited) Preparation of Boron-Doped Nanodiamond and Its Application to Aqueous Electrochemical Capacitors

Boron-doped diamond (BDD) is known to be a functional electrode material that can be used in various electrochemical applications such as sensitive electroanalysis and efficient electrolysis, based on the unique electrochemical properties including wide potential window and low background current, as well as extreme physical/chemical stabilities. Usually, BDD electrodes are prepared by deposition of a polycrystalline BDD thin film on a conductive substrate. In this form, the specific surface area is too small to be used as an electrochemical capacitor. Thus, we have developed boron-doped nanodiamond (BDND) powder as a conductive diamond powder with a large specific surface area. BDND exhibits wider potential window in aqueous electrolytes than activated carbon (AC). Therefore, the BDND is expected to be used for an electrode material of aqueous EDLC with a large cell voltage.Nanodiamond powder (primary particle size: 4 nm) was used as a substrate material for BDND. BDD was deposited on the agglomerate of dry nanodiamond powder via microwave plasma-assisted chemical vapor deposition (CVD). The as-deposited BDND was then treated by air oxidation at 425 °C to minimize sp2 carbon components to obtain BDND. Test electrode was prepared by casting an ink containing BDND on a glassy carbon disk electrode as a current collector. For an EDLC pouch cell, BDND paste containing PVDF binder was applied on the both sides of a titanium sheet current collector to form an electrode. Two electrodes with a separator in between was put in a plastic bag and aqueous electrolyte was poured in the bag to form a pouch cell.The BDND was found to show a relatively large specific surface area of 650 m2 g−1 and good conductivity of ~1 S cm−1. CV in 1 M H2SO4 at the BDND test electrode in a three-electrode configuration showed a wide potential window of 3 V, which was significantly wider than that of an AC test electrode (1.5 V). In a symmetric two-electrode system, cell voltage of a CV in 1 M H2SO4 was found to be larger at the BDND electrode (1.8 V) than at the AC electrode (0.8 V). Therefore, wide potential window of the BDND was confirmed to be useful for creation of an aqueous EDLC with a large cell voltage. In addition, the use of saturated NaClO4 as an electrolyte was shown to be effective for an extremely large cell voltage of 2.8 V, which can further enlarge the energy and power densities of an aqueous EDLC. CV of BDND/saturated NaClO4 system exhibited a high energy density of 20 Wh kg−1 and a high power density of 104 W kg−1. Similar charge-discharge properties were also shown at EDLC pouch cells with BDND/concentrated NaClO4 system.

Hydrodynamic Jet Cavitation to Process Natural Graphite into High C-Rate Capable Anodes for Use in Pouch Cells

A novel method for processing natural graphite for use in high performance Li-ion batteries is presented. The processing method utilises hydrodynamic jet cavitation (HJC) to produce a highly conductive graphite powder from a natural graphite precursor with the only consumables being electricity and water (process shown in Figure 1a). The HJC process produced a thin (carbon black)-like coating on the surface of the graphite particles, giving the material a higher conductivity compared to two other commercial graphite samples. In rate capability tests, LFP // graphite full cells produced a specific capacity 500% than the commercial graphite anodes (Figure 1c).This patented process is carbon neutral and aims to help the global electric vehicle (EV) market to produce high performing EVs whilst simultaneously lowering the high carbon footprint from producing the battery packs that power them.An in-depth characterisation study is performed on the powders, electrode slurry formulations and cells to determine how the surface characteristics of the graphite particles affect their electrochemical performance. The graphite powders were separated by particle size and tested in both coin and single layer pouch cells. Through SEM analysis, HJC graphite powders show a higher proportion of edge planes compared to basal planes, providing more sites for Li (de-)intercalation during charging and discharging (shown in Figure 1b). This explains their higher capacity at higher C-rates (5C + 10C) compared to the commercial standards. However, it is also found that the higher proportion of edge planes results in a substantially thicker solid electrolyte interphase (SEI) during cycling, consuming more of the Li inventory; resulting in a poorer initial coulombic efficiency and cycle life. The addition of electrolyte additives such as Lithium difluorooxalatoborate (LiDFOB), vinyl carbonate (VC) and VC derivatives are used to improve the coulombic efficiency of the coin and pouch cells. Figure 1

Closed-Loop Recycling of Wearable Electronic Textiles.

Wearable electronic textiles (e-textiles) are transforming personalized healthcare through innovative applications. However, integrating electronics into textiles for e-textile manufacturing exacerbates the rapidly growing issues of electronic waste (e-waste) and textile recycling due to the complicated recycling and disposal processes needed for mixed materials, including textile fibers, electronic materials, and components. Here, first closed-loop recycling for wearable e-textiles is reported by incorporating the thermal-pyrolysis of graphene-based e-textiles to convert them into graphene-like electrically conductive recycled powders. A scalable pad-dry coating technique is then used to reproduce graphene-based wearable e-textiles and demonstrate their potential healthcare applications as wearable electrodes for capturing electrocardiogram (ECG) signals and temperature sensors. Additionally, recycled graphene-based textile supercapacitor highlights their potential as sustainable energy storage devices, maintaining notable durability and retaining ≈94% capacitance after 1000 cycles with an areal capacitance of 4.92 mF cm⁻2. Such sustainable closed-loop recycling of e-textiles showcases the potential for their repurposing into multifunctional applications, promoting a circular approach that potentially prevents negative environmental impact and reduces landfill disposal.

Synergistic effect of nickel and graphite powders on the thermoelectric properties of ultra-high-performance concrete containing steel fibers and MWCNTs

Synergistic effect of nickel and graphite powders on the thermoelectric properties of ultra-high-performance concrete containing steel fibers and MWCNTs

Conductive Powder Binders for Production of Carbon Composites

Conductive Powder Binders for Production of Carbon Composites

Preparation and Properties of Conductive Aluminum Powder (Al@Si@C) for Water-Borne Heavy-Duty Anticorrosive Coatings

To improve the storage stability and conductivity of aluminum powder in an aqueous environment, the surface of aluminum powder was treated to form silica film by the sol–gel method, then was treated with conductive modification to introduce nanocarbon black particles so that conductive aluminum powder could be prepared to solve the application bottleneck of aluminum powder in water-borne heavy-duty anticorrosive coatings. The structure, surface morphology, and composition of the modified aluminum powder were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). The corrosion resistance and electrochemical properties were measured using a hydrogen evolution test and an 2electrochemical test. The results showed that there was a compact SiO2 film formed on the surface of the prepared conductive aluminum powder, and the conductive filler nanocarbon black was uniformly grafted on the surface. According to the hydrogen evolution test at 100 h/50 °C, conductive aluminum powder with 5 wt% carbon black exhibited the best hydrogen evolution effect, with a hydrogen evolution amount of only 0.5 mL. The prepared conductive aluminum powder was applied to the water-borne coatings, and the storage stability test, electrochemical polarization test, and neutral salt spray test were further conducted. The water-borne coatings prepared with conductive aluminum powder still showed good performance and had no reaction after 6 months of storage. Compared with the coating containing SiO2-modified aluminum powder, the coating exhibited better corrosion resistance.

Preparation of self-assembled graphene materials with assisted multi-structured TiO2: Internal three-phase heterojunction built by doping with Al3+

Preparation of self-assembled graphene materials with assisted multi-structured TiO2: Internal three-phase heterojunction built by doping with Al3+

Improved thermal conductivity of high‐density polyethylene by incorporating hybrid fillers of copper powders and silicon carbide whiskers

AbstractIn this paper, highly electrically and thermally conductive copper powders (Cu) and electrically insulative yet thermally conductive silicon carbide whiskers (SiCw) were selected as functional fillers and high‐density polyethylene (HDPE) was used as the matrix to prepare thermal conductive composites. By controlling the amount of Cu at 30 vol% which is below percolation threshold, the volume resistivity of the composites is maintained above 1014 Ω cm. The results showed that SiCws entered the area which was not occupied by Cu particles and they played a bridging effect among Cu particles, thereby promoting the formation of intact thermal conductive pathways that contributed to improving the thermal conductivity of corresponding composites. The combination of SiCw:Cu = 3:1 at a filler content of 30 vol% resulted in a thermal conductivity as high as 1.921 W/mK, which is 380% higher than pure HDPE.

Investigation on characteristic of vanadium trioxide insulation mixed with metal powder for rare-earth barium copper oxide coils

This study examined the turn-to-turn contact resistance (R ct) between rare-earth barium copper oxide (REBCO) tapes and layers of vanadium trioxide (V2O3) and V2O3 mixed with metal powder mixture. V2O3 in single crystal structure was electrically characterised to exhibit resistivity with negative temperature dependence, allowing the turn-to-turn insulation to self-regulate the current bypass between REBCO tapes. To facilitate effective quench protection of V2O3-insulated REBCO magnets above the metal-insulator transition temperature (T rt), R ct must be further reduced to a level similar to those of non- and metal as insulated (NI and MI) REBCO magnets. Thus, we explored the mixing of conductive metal powders such as molybdenum (Mo) with V2O3 paste and investigated the transition properties of R ct. The resistance versus temperature characteristics, microscopic morphologies of the V2O3 layers, and thermal conductivity (k v) were appropriately assessed to determine the effects of mixing the metal powder with V2O3. The R ct of virgin V2O3 exhibited variations of 107–105 μΩ cm2 under 77–293 K. As the mixing concentration of the metal powder was increased, the reduction magnitude on R ct increased for > T rt (approximately 150 K). Furthermore, the transition slope became gentler for a wider temperature range of < T rt. For metal powder concentrations exceeding 50 wt%, R ct decreased by approximately 2 orders of magnitude (∼103 μΩ cm2) for > 150 K compared with that for virgin V2O3 paste. Moreover, compared to that of pure V2O3, k v demonstrated a remarkable increase of approximately 352% at 91 K for Mo powder mixed at a concentration of 60 wt%. The improved electrical and thermal properties of the V2O3 insulation layer owing to the mixing of metal powders can help REBCO magnets operate in an insulated state under normal conditions and effectively convert to a non-insulated state under quenching.