Tungsten Carbide Nanoparticles Research Articles

Mechanical properties of tungsten carbide nanoparticles filled epoxy polymer nano composites

Growth of latest composite materials or alteration of existing composite materials to get mechanically durable structural components is the real challenge for the most of the industrial engineers. In the present work, change in the performance of epoxy polymer nanocomposites, such as mechanical and physical properties by the addition of Tungsten Carbide (WC) nanoparticles in to it has been studied. Different weight percentages (1%, 2%, 3% and 4%) of particles were added to the neat epoxy. Tensile test, flexural test and amount of void content present in composite were studied. Experiments results show that improvement in both tensile and flexural strength at 2% of particles loading. While At higher percentage of particles loading, there is decrease in mechanical properties has been observed.

Novel zinc/tungsten carbide nanocomposite as bioabsorbable implant

There is a lack of bioabsorbable materials with adequate mechanical strength suitable for implant applications that provide temporary support while tissue integrity is restored, especially for pediatric applications. Bioabsorbable metals have emerged as an attractive choice due to their combination of strength, ductility, and biocompatibility in vivo. Zinc has shown great promise as a bioabsorbable metal, but the weak mechanical properties of pure zinc limit its application as an implant material. This study investigates zinc-tungsten carbide (Zn-WC) nanocomposite as a novel material for bioabsorbable metallic implants. Ultrasound-assisted powder compaction was used to fabricate Zn-WC nanocomposites. This study includes the material characterization of microstructure, microhardness, and degradability. Results showed that tungsten carbide nanoparticles enhanced the mechanical properties of Zn, and maintained the favorable corrosion rate of pure Zn. These results encourage further investigation of Zn-WC nanocomposites for biomedical applications with the ultimate goal of creating safe and efficacious bioabsorbable metallic implants for many clinical applications.

High performance of microbial fuel cell afforded by metallic tungsten carbide decorated carbon cloth anode

Developing high efficient anode is of great significances for the application of microbial fuel cells. Tungsten carbide attracts our attention due to its platinum-like metallic conductivity, corrosion resistance and low cost. In this work, tungsten carbide nanoparticles are pasted on carbon cloth as the anode for mediator-less microbial fuel cell. The surface of obtained anode is quickly attached with highly dense biofilm that accounts for a fast extracellular electron transfer rate. Microbial community structure analysis at the genus level shows that the main exoelectrogens are Geobacter, Geothrix and Pseudomonas, all of which can completely decompose acetate and transfer electrons through both direct and indirect extracellular electron transfer pathways. Consequently, it contributes to higher power density (3.26 W m−2), better chemical oxygen demand removal rate (95.5%) and greater coulombic efficiency (83.2%), which are 2.14-fold, 1.22-fold, 1.71-fold of that obtained by the naked carbon cloth anode (1.52 W m−2, 78.1%, 48.6%), respectively. Especially for the coulombic efficiency, it is obviously higher than others’ reported works in the similar microbial fuel cells system, being attributable to the synergistic effect of exoelectrogen. In virtue of the above advantages, tungsten carbide is a potential candidate for the further application of microbial fuel cells.

The effect of tungsten carbide nanoparticles added to electrolyte on the composition and properties of oxide layers formed by plasma electrolytic oxidation on pre-eutectic silumin

The effect of a low concentration (500 mg/L) additive of tungsten carbide (WC) nanoparticles (NPs) with a dispersion of 50–80 nm in an electrolyte on the structure, composition, and properties of oxide layers formed by plasma electrolytic oxidation (PEO) on 357.0 aluminum-silicon alloy (7.5 wt.% Si) was investigated. The oxide layers were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectral microanalysis (EDXMA), X-ray diffraction analysis (XRD), and instrumental indentation. The thickness, roughness, microhardness, and wear resistance of the oxide layers were determined. It was found that the addition of WC nanoparticles at a concentration of 500 mg/L into the base electrolyte leads to an increase in the average thickness of the layer from 73 μm to 92 μm. It was found that the average microhardness was increased from 882 MPa to 1307 MPa, and the average wear was decreased from 592·10−9 g/(N·m) to 81·10−9 g/(N·m).

Synthesis of Mo2C and W2C Nanoparticle Electrocatalysts for the Efficient Hydrogen Evolution Reaction in Alkali and Acid Electrolytes.

The synthesis of low cost, high efficacy, and durable hydrogen evolution electrocatalysts from the non-noble metal group is a major challenge. Herein, we establish a simple and inexpensive chemical reduction method for producing molybdenum carbide (Mo2C) and tungsten carbide (W2C) nanoparticles that are efficient electrocatalysts in alkali and acid electrolytes for hydrogen evolution reactions (HER). Mo2C exhibits outstanding electrocatalytic behavior with an overpotential of −134 mV in acid medium and of −116 mV in alkaline medium, while W2C nanoparticles require an overpotential of −173 mV in acidic medium and −130 mV in alkaline medium to attain a current density of 10 mA cm−2. The observed results prove the capability of high- and low-pH active electrocatalysts of Mo2C and W2C nanoparticles to be efficient systems for hydrogen production through HER water electrolysis.

Synthesis of Tungsten Carbide Nanomaterials in Triple DC Thermal Plasma Jet System.

The tungsten carbide nanomaterials were synthesized in the triple DC thermal plasma jet system using refractory tungsten, and carbon sources such as multi wall carbon nanotube (MWCNT), amorphous carbon and methane. The starting materials were evaporated in the high temperature region of triple plasma jet, then condensed particles were prepared in nanoscale under 100 nm. The effect of carbon sources was investigated on a view of crystal phase structure and morphology. W₂C crystal nanoparticles were mainly synthesized and WC and WC1-x phase nanoparticles were observed additionally with all carbon sources. From MWCNT starting material, tungsten carbide attached MWCNT composite were produced with spherical tungsten carbide nanoparticles. In case of amorphous carbon, spherical and rod-shaped tungsten carbide was synthesized. Only spherical tungsten carbide nanoparticles were synthesized by methane. In addition, it was revealed that the main crystal structure was changed from W₂C to WC1-x by increasing W/CH₄ composition ratio.

Tungsten carbide nanoparticles show a broad spectrum virucidal activity against enveloped and nonenveloped model viruses using a guideline-standardized in vitro test.

Five tungsten carbide nanoparticle preparations (denoted WC1-WC5) were investigated for broad spectrum virucidal activity against four recommended model viruses. These are modified vaccinia virus Ankara (MVA), human adenovirus type 5 (HAdV-5), poliovirus type 1 (PV-1) and murine norovirus (MNV). All virucidal tests were performed two to five times using the quantitative suspension test, which is a highly standardized test method to evaluate the virucidal efficacy of disinfectants in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Quantitative detection of viruses was conducted by endpoint titration and quantitative real-time PCR. Results showed that three of the five tested compounds (WC1-WC3) were able to reduce the infectivity of all model viruses by at least four log10 of tissue culture infective dose 50% per ml after 15min, whereas the other two compounds exhibited only limited efficacy (WC4) or showed cytotoxicity (WC5). Virucidal activity of nanoparticles increased with incubation time and a dose-effect curve showed dependence of virucidal activity with particle concentration. Whereas WC1-WC4 showed little cytotoxicity, WC5 which was doped with copper exhibited a significant cytotoxic effect. These findings propose tungsten carbide nanoparticles to be very promising in terms of new disinfection techniques. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study investigates the virucidal activity of tungsten carbide nanoparticles using the quantitative suspension test in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Due to highly standardized assay conditions, results of this test are considered very reliable for evaluation of the virucidal activity of disinfectants. Broad-spectrum activity and high efficacy of three different tungsten carbide nanoparticles preparations is concluded.

Formation of tungsten carbide nanoparticles by wire explosion process

AbstractTungsten carbide nanoparticles (NPs) were synthesized by wire explosion process (WEP) in gas ambient as carbon source. Formation of tungsten carbide (WC1−X) in a single step by WEP using methane and argon‐acetylene mixture as carburizing medium, is detailed. X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to observe the phase and morphology of the produced NPs. In WEP, morphology and phase of NPs are controlled using different levels of energy ratio, K (ratio of energy supplied to wire and sublimation energy of wire), type and pressure, P of ambience. High purity WC1−X NPs was synthesized in methane ambience with a high K (=19) and a high P (270 kPa). A thorough study has been made to understand the impact of type of carburizing medium. Methane‐acetylene mixture gave two phases of carbides. Argon‐acetylene ambience provided complete carburization in specific cases. In general, the formed NPs are spherical in shape. Formation mechanism of tungsten carbide NPs is detailed in the work.

Hybrid phthalonitrile‐based materials with advanced mechanical and nuclear shielding performances

AbstractPhthalonitrile resins as one of the leading high performance polymers are currently used in highly exigent applications. Herein, aiming to achieve the best combination of mechanical, thermal, and nuclear shielding performances, we prepared hybrid materials based on the typical phthalonitrile resin and the silane surface modified chopped carbon fibers and tungsten carbide nanoparticles. The obtained results suggested that a synergistic combination between the three constituent was clearly achieved leading to excellent mechanical and gamma rays shielding properties. For instance, the tensile and bending strengths reached up to 505 and 584 MPa for the composite containing 20 and 30 wt% of carbon fibers and tungsten carbide nanoparticles, respectively. Similarly, the gamma rays screening ratio also reached the exceptional value of 39% for the same 2 cm thick hybrid. Finally, the as such described hybrid materials proved that a multi‐approach strategy is often the best solution to achieve the requirements of highly exigent applications.

Fabrication of Al–WC gradient nano-composite via centrifugal casting method

AbstractIn this work, fabrication and characterization of aluminum gradient composites reinforced by nano-particles of tungsten carbide via the centrifugal casting method were studied. In order to prepare a mixture of aluminum and tungsten carbide powders, a high energy planetary ball mill was used. The master-alloy was added to A356 aluminum matrix by horizontal centrifugal casting at different rotation speeds to synthesize Al-5 wt.% WC. The results of X-ray diffraction and scanning electron microscopy analysis confirmed a homogeneous powder in nanometer scale through mechanical milling. Centrifugal casting at speeds of up to 1300 RPM is a suitable method for production of Al–WC gradient nano-composites. By increasing the rotation speed, reinforcement phases are transmitted into the outer layers of cast samples. An agglomeration of hard WC phase leads to improvement of surface hardness and wear resistance.

Tungsten carbide as a deoxidation agent for plasma-facing tungsten-based materials

Tungsten (W) and various composites are being considered as the primary plasma-facing materials for fusion reactors. Like all engineering materials, they contain certain levels of impurities, which can have an important impact on mechanical properties. In the present work, oxygen was identified as a major impurity in our starting tungsten powder. At elevated temperatures, the presence of interstitial elements such as oxygen leads to the formation of an oxide-rich tungsten phase at the tungsten grain boundaries. In this study, we determined the capacity of tungsten carbide (WC) nanoparticles to remove the oxide impurities from a tungsten body. Tungsten composites with 0.05, 0.25 and 0.51 wt. % carbon (C) in the form of WC were sintered using a field-assisted sintering technique (FAST) at 1900 °C for 5 min. The sintered samples were characterized using field-emission scanning and transmission electron microscopy. Thermodynamic and kinetic considerations allowed us to determine the optimum theoretical amount of WC to prevent the in-situ formation of WO2.

Sliding wear and solid particle erosion response of aluminium reinforced with tungsten carbide nanoparticles and aluminide particles

AbstractIn the present effort, aluminium matrix composites (AMCs) were produced by the addition of submicron‐sized WC particles of low (up to 2.5 vol%) content into a melt of Al1050. Casting was assisted by the use of K2TiF6 as a wetting agent and mechanical stirring in order to limit particle clustering. Particle distribution was reasonably uniform comprising both clusters and isolated particles. Various different reinforcing particles' phases were identified, both in situ (Al‐W, Al‐Ti, and Al‐W‐Ti intermetallic phases) and ex situ (WC particles) of various morphologies shapes and sizes. Increase of the reinforcing particle content led to an increase of the tendency for clustering. The wear properties of the composite were examined by dry sliding wear. The worn surfaces and the produced debris were examined by SEM‐EDX, and an effort to correlate the wear response of the produced materials with the matrix and the reinforcing phase characteristics was attempted. In general, the increase of the reinforcing phase content led to an improvement of the sliding wear response. Solid particle erosion experiments were carried out for impact angles of 30°, 60°, and 90°. Τhe eroded surfaces were examined with SEM‐EDX, and possible erosion mechanisms were proposed based on morphological and other material characteristics. Intensive particle clustering seemed to deteriorate the erosion resistance of the systems. Medium concentrations of the reinforcing particles (1.0‐1.5 vol% WC) are proposed as a recipe for optimum sliding wear and solid particle erosion resistance behavior.

Ultradispersed WxC nanoparticles enable fast polysulfide interconversion for high-performance Li-S batteries

Li-S batteries are a promising next-generation battery technology but are confronted with a series of fundamental challenges, in particular the notorious shuttle effect of soluble polysulfide intermediates. Current research efforts are mostly focused on designing proper host materials for the entrapment and immobilization of polysulfides. Herein, we demonstrate that electrocatalysis may play an unexpected role in Li-S batteries. Nanosized tungsten carbide particles dispersed on the carbonaceous support are prepared from the pyrolysis of phosphotungstic acid-functionalized metal-organic frameworks. Both experimental measurements and theoretical calculations demonstrate that they not only have strong affinity toward polysulfide intermediates, but also significantly accelerate the reduction of low-order polysulfides that is otherwise kinetically challenged. Using these supported tungsten carbide nanoparticles as the cathode catalyst, our Li-S batteries achieve large capacity, excellent cycling stability and impressive rate capability.

Erratum to: Modification of Weld Metal with Tungsten Carbide and Titanium Nitride Nanoparticles in Twin Submerged Arc Welding

Received February 27, 2018

Prediction of initial particle size of the tungsten carbide synthesized by electrical discharge erosion method based on general dynamic equation of aerosols

In the process of synthesizing nanoparticles within an aerosol, the initial size of the particles and their process characteristics have a crucial effect on extent of adhesion between them and the formation of final nanoparticles. In the present study, a mathematical model based on the general dynamic equation of aerosols was used to predict the initial size of tungsten carbide nanoparticles, which was synthesized using electrical discharge erosion. A method was developed to calculate all of the parameters required for the mathematical model, solely with the input and output values of the electrical discharge process without the need for any external data. This model was evaluated through the synthesis of nanoparticles under an atmosphere of argon and nitrogen. The parameters required for the analytical model were obtained from experimental data, and its results were verified by comparing them with the results of experiments conducted under specific case-study parameters, which predicted a smaller size (approximately 18%) of synthesized nanoparticles in argon gas compared with nitrogen gas. Based on the theoretical results' remarkable consistency with the experimental data, this model can be used to adjust the input parameters of the electrical discharge erosion process to obtain primary tungsten carbide nanoparticles of desired sizes.

Performance of diamond drill bits with hybrid nanoreinforced Fe-Ni-Mo binder

In this study, the possibility of applying novel Fe-Ni-Mo-based alloys in diamond tool binders is shown. Nanoparticles of tungsten carbide, hexagonal boron nitride, and carbon nanotubes were used for binder reinforcement. It is established that simultaneous addition of all three types of nanoparticles allows one to achieve the highest mechanical and tribological properties of Fe-Ni-Mo alloy. The machining tests of drill bits equipped with experimental binders demonstrated that nanoparticle reinforcement enhances wear resistance of tools, their service life, and diamond retention within the working layer. Furthermore, an analysis of the tool surface and diamond condition after tests showed a good correlation between binder strength and diamond retention capacity. The positive role played by tungsten carbide nanoparticles involves both Orowan strengthening of the binder and a better chemical bonding at the binder–diamond interphase.

Study on electrical behaviour of copper and its alloys containing dispersed nanoparticles

Nanoparticles can be added to metals to tune their properties for numerous applications. Recently extensive research has been conducted to measure the mechanical properties of nanoparticle reinforced metals. However, few theories exist to understand how nanoparticles interact with metals to affect their electrical performance, partly due to the difficulty in producing bulk metal samples, containing dispersed nanoparticles. In this work, copper and copper alloys (Cu, Cu-40 wt% Zn, and Cu-60 wt% Ag) containing dispersed tungsten carbide (WC) nanoparticles of more than 20 vol% were successfully fabricated via solidification processing. The experimental results show that copper and its alloys with an increasing volume fraction of nanoparticles, the electrical conductivity of the samples decays exponentially. Therefore, a theoretical model, compatible with the Nordheim's rule was established to predict the electrical behaviour of metals containing dispersed nanoparticles. This new model on the electrical behaviour of copper nanocomposites is experimentally validated by low-temperature resistivity measurements and electronic heat capacity measurements above Debye temperature.

Production of tungsten carbide nanoparticles through Micro-EDM and its characterization

Abstract The development of nano technologies have created renewed interest among researchers and scientist about various ingenious applications of these nano technologies. Production of nanoparticles with controlled morphology, size, shape and composition, is crucial step toward nano-technological applications. The present paper is focused on production of tungsten carbide nanoparticles through micro-EDM. In micro-EDM process after discharge high heat is generated, this is responsible for melting and evaporating of material in dielectric medium to form nanoparticles. Change in dielectric show the remarkable effect on the Metal Removal Rate (MRR) and Tool Wear Rate (TWR), size, morphological structure of produced nanoparticle. The generated tungsten carbide nanoparticles were characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy. EDS result shows the sample contains carbon and tungsten which form tungsten carbide.

Metallic tungsten carbide nanoparticles as a near-infrared-driven photocatalyst

In this study, we present the LSPR effect and full spectrum photoabsorption of metallic WC for the direct NIR-driven photoelectric conversion and photocatalytic degradation of organic pollutants.

High-performance copper reinforced with dispersed nanoparticles

Copper (Cu) has high electrical conductivity and is widely used for many industrial applications. However, pure Cu is very soft and improving the mechanical properties of Cu comes at the great expense of electrical and thermal conductivity. In this work, high-performance Cu with superior mechanical properties and reasonable electrical/thermal conductivity was fabricated using a scalable two-step method. First, Cu micro-powders with uniformly dispersed tungsten carbide (WC) nanoparticles were created by a molten salt-assisted self-incorporation process. A bulk nanocomposite was then obtained by melting the powders under pressure. The as-solidified Cu with 40 vol% uniformly dispersed WC nanoparticles exhibits high hardness, a yield strength over 1000 MPa, a Young’s modulus of over 250 GPa, and reasonable electrical and thermal conductivity.