WC Nanoparticles Research Articles

Pulse plating of Ni–B/WC nanocomposite coating and study of its corrosion and wear resistance

ABSTRACTThe aim of this study is to investigate the impact of WC content on the properties of the Ni–B/WC nanocomposites deposited by the pulse method. It is obtained that, although by addition of WC nanoparticles to the bath in initial steps (WC 4 and 8 g l−1), the grain size was increased and hence mechanical and electrochemical properties got worse, but at the higher amount of WC (WC 12 g l−1), due to the formation of the fine and packed structures, the great corrosion and wear resistance was achieved. The corrosion resistance of the Ni–B/WC12 g l−1 coating is 59,967 Ω and wear weight loss is 2.1 mg cm−2 with the friction coefficient of 0.64.

Enhanced thermal stability in Cu-40 wt% Zn/WC nanocomposite

A major challenge for alloy applications is to achieve thermal stability of phase transitions and anti-oxidation properties. Given the stability of ceramic nanoparticles, we propose the incorporation of WC nanoparticles as a novel way to tune the thermal stability of Cu-40 wt% Zn, which is an important alloy known as naval brass. In situ XRD and DSC results confirmed the enhanced thermal stability of Cu-40 wt% Zn/10 vol% WC nanocomposites at higher temperatures were observed for both phase transitions and oxidation. The underlying mechanisms behind Zn diffusion during phase change and oxygen contact are discussed to understand the phenomena. Optical profiles along with SEM and FIB images reveal the morphologies and microstructures of different stages and give supporting information for the above argument. Due to the kinetic and dynamic impedance on Zn diffusion and the intrinsic stability of WC, the higher thermal stability in Cu-40 wt% Zn/WC is achieved. This study provides an effective way to tune thermal stability of alloys, control phase change, and vary post-oxidation morphology.

Tribological behavior of Mg-WC nano-composites at elevated temperature

The present study evaluates the tribological behavior of Mg-WC nano-composites at elevated temperature. Mg-WC nano-composites with varying wt% of WC (0.5%, 1%, 1.5% and 2%) have been prepared using ultrasonic vibration assisted stir casting method. Characterizations of composites are performed with the help of optical microscopy, scanning electron microscopy and energy dispersive x-ray patterns. Characterization results confirm the presence of reinforcement phase and microstructural integrity of composites. Micro-hardness and density of composites and base alloy are studied. Effects of operating temperature, applied load and sliding distance on wear and friction characteristics of composites are examined in a high temperature tribotester under dry sliding conditions. Operating temperature is varied over a range of 50 °C to 250 °C while applied load is varied from 20 N to 40 N. Micro-hardness results confirm the improvement in mechanical properties of composites in presence of WC reinforcement. Wear and friction behavior of magnesium alloy gets substantially enhanced with WC nano-particles being incorporated as reinforcement. With incorporation of 2 wt% of WC, wear rate and coefficient of friction of magnesium alloy gets reduced by about 75% and 15% respectively at 20 N and 200 °C. Effects of thermal softening in composites get negated by the presence of harder ceramic phase through formation of some hardened layer at the contact regime.

Thermal- and wear-resistant alloy arc welding depositions using composite and flux-cored wires with TiN, TiCN, and WC nanoparticles

The studied GMAW processes – splitting the electrode into two wires, oscillation of the electrode, and cooling the weld pool metal with filler wire – reduce the arc thermal impact on the nanoparticles and improve their mass transfer into the solidifying metal. The nanoparticles in the wire fillers are recommended to be within 0.3–0.6 wt.%. Surfacing with two composite wires containing WC nanoparticles improves the properties of metal with a Ni3 Al-based matrix at temperatures within 1000–1200 °C. WC particles influence the composite metal formation, initiating precipitation from the γ+γ' solid solutions of strengthening phases in the form of intermetallides of (Zr,Ta,W)C type and ZrC carbides. The surfacing process with oscillation of the electrode flux-cored wire with TiCN particles improves the thermal and plastic resistance of the metal, with a matrix of the C–Fe–Cr–Ni–Mo–Ti–N system at temperatures within 750–950 °C. The composite metal with fine grains is formed under the influence of nucleation centres, in the form of TiCN nanoparticle clusters. The filler flux-cored wire with ultra-disperse TiN particles introduced in the weld pool, improves the resistance of deposited metal of the Fe–C–Cr–Mo–Ni–B system to abrasive wear at 500 °C. TiN particles initiate precipitation from the deposited metal matrix of strengthening phases in the form of (Ti, Mo)C 1−х carbides that are 1–4 μm in size. In conjunction with additional cooling of the melt near the solidification front, this helps to form the MMC structure in the melt.

Thin Nickel Layer with Embedded WC Nanoparticles for Efficient Oxygen Evolution

Developing active and stable electrocatalysts for the oxygen evolution reaction (OER) is essential to enhance the efficiency of water splitting. Herein, we report a nickel/tungsten carbide (Ni/WC) composite catalyst in which WC nanoparticles are embedded underneath thin Ni layers as a highly active OER catalyst in an alkaline electrolyte. The thin Ni layer has a modulated electronic structure stemming from the interaction with the WC. The Ni/WC composite exhibits excellent OER activity and durability in a 1 M KOH solution. The turnover frequency of the Ni/WC composite (0.58 s–1) is increased by approximately 5.8 times relative to that of the Ni nanoparticles (0.10 s–1). The significant increase in catalytic activity of the Ni/WC composite can be attributed to the adsorption property change originating from the interaction between the Ni layers and the WC nanoparticles. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation results show that the electronic structure of the N...

Dry sliding tribological behavior of AZ31-WC nano-composites

Abstract The present study investigates the effect of WC nano-particles on tribological behavior of magnesium based nanocomposites for varying wt% of WC (0.5, 1, 1.5 and 2 wt%). Nanocomposites are fabricated using ultrasonic vibration assisted stir casting method. Optical microscopy, scanning electron microscopy and energy dispersive x-ray patterns are used to characterize the base alloy and fabricated composites. Micro-hardness values of as-cast composites are obtained through Vicker's micro-hardness tester. Friction and wear behavior of fabricated composites are studied using pin-on-disk type tribotester at room temperature under dry sliding condition. Operating load range is 10–40 N while sliding speed range is 0.1–0.4 m/s. Characterization of Mg-composites confirms particle inclusion as well as better microstructural integrity with increase in reinforcement. Hardness value of composites increases with increase in the amount of WC nano-particles. Wear and friction behavior of base matrix are also enhanced due to incorporation of WC nano-particles. Different wear mechanisms occurring at the contact surfaces are ascertained through SEM images and EDAX patterns. Oxidation in the tested surface is also identified through SEM and EDAX. This yields better tribological behavior in composites.

Simultaneous increase of friction coefficient and wear resistance through HVOF sprayed WC-(nano WC-Co)

Generally, well wear resistance corresponds to low friction coefficient. While, well wear resistance and high friction coefficient are needed in brakes for short braking distance and long serving life. Ceramics possess high hardness which correspond well wear resistance. Cobalt is often used as bond phase of tungsten carbide ceramic, which will increase the toughness of tungsten carbide. While, the stiffness of WC-Co will decrease after cobalt is introduced into tungsten carbide, which will lead to the decrease of friction coefficient. To increase the stiffness and the friction coefficient of WC-Co, nano WC particles were introduced into cobalt binder phase which formed WC-(nano WC-Co).In this work, WC-(nano WC-Co) coatings were prepared through high velocity oxygen fuel (HVOF) spray on the vermicular iron substrate in order to increase friction coefficient and wear resistance simultaneously. The microstructure, mechanical property and wear performance of the coating were investigated.It was found that the microhardness of WC-(nano WC-Co) coatings had the highest hardness of 1393 ± 13 HV with 50% nano WC-10Co-4Cr. Meanwhile, its friction coefficient was obviously increased to 0.7, which was three times higher than that of the vermicular cast iron and higher than both of the micro-sized and nano sized WC-Co. Its wear mass loss of WC-(nano WC-Co) coating was much lower than that of the vermicular cast iron and lower than both of the micro-sized and nano sized WC-Co. The friction coefficient and wear resistance of WC-(nano WC-Co) were increased simultaneously.

Fe–Ni Invar alloy reinforced by WC nanoparticles with high strength and low thermal expansion

Invar is a solid solution alloy that offers high-dimensional stability. It is challenging for traditional methods to strengthen Invar alloys without a significant increase in the coefficient of thermal expansion (CTE). In this work, WC nanoparticle-reinforced Invar nanocomposite was manufactured. The microstructures, mechanical properties, and thermal expansion behavior were investigated. It was found that the Invar alloy was effectively strengthened by WC nanoparticle reinforcement without significant elevation of its CTE. The Invar–WC nanocomposite exhibits an enhanced yield and tensile strength of 440 and 795 MPa, an increase of 60% and 77% from commercial Invar alloy, and a moderate ductility of 22.7% in annealed state. In cold-rolled state, The Invar–WC nanocomposite exhibits a high tensile strength of 1050 MPa, an increase of 46% from commercial Invar alloy, while retaining 4.5% ductility. A record low CTE value of 2.61 × 10−6/°C and an enhanced Young’s modulus of 185 GPa, up from 140 GPa, were also achieved. It was found that WC leads to a lower CTE at higher temperature compared to unreinforced Invar.

Correlation between the microstructure and magnetic configuration in coarse-grain inhibited hot-deformed Nd[sbnd]Fe[sbnd]B magnets

Stress-induced alignment of Nd2Fe14B nanograins along (001) planes represents a practical process with which to create uniaxial high-anisotropy NdFeB magnetic materials. The residual non-oriented coarse-grain defect at ribbons’ surfaces not only deteriorates the [001]-oriented structure but also facilitates the low-field nucleation of reversed magnetic domains. Although the local structural defect has proved to be controllable via doping refractory ceramic nanomaterials, the natures of coarse-grain suppression and corresponding magnetic configuration variation remain poorly known. Herein, we comprehensively discuss the correlation between structures and magnetic configurations to address the role of WC dopants in the kinetics of stress-induced deformation system. The statistical data suggest that the reinforced stress caused by WC nanoparticles effectively suppresses the size of Nd2Fe14B grains and induces their anisotropic growth. Simultaneously, the evolved (006) polar figures further confirm that the crystallographic orientation of interfacial Nd2Fe14B grains is also improved by reinforced stress. The analysis for magnetic configurations around dopants confirms that the coarse-grain inhibited structure reduces the low-field nucleation probability of reversed magnetic domains. Relying on their combined effect, the coercivity is increased by about 12%. These observations are further verified by the micromagnetic simulation computations. All these above findings may enrich the knowledge of stress-induced deformation mechanism and deepen the fundamental understanding of the correlation between structure and magnetic features.

Facile fabrication and enhanced properties of Cu-40 wt% Zn/WC nanocomposite

High loading of WC nanoparticles was successfully incorporated into the alloy system Cu-40 wt% Zn by molten salt stirring method. Given the energy balance of thermal energy, van der Waals interaction and inter-particle barrier, the expected pseudo-dispersion of WC was stable. In order to evaluate the materials functional applicability, the mechanical, electrical and anti-corrosion properties of fabricated Cu-40 wt% Zn/WC nanocomposite were measured and theoretically analyzed; with an increase of WC nanoparticles to 23.0 vol%, the microhardness increases to ∼200.00 HV and the Young's modulus to ∼179.00 GPa. Even though the electrical conductivity decreases to ∼4.17 MS/m, the corrosion rate for Cu-40 wt% Zn/WC is significantly lowered (∼0.017 mm/yr for 12.5 vol% WC).

Fatigue Failure Analysis on Precracked 304 Stainless Steel Components Repaired by Laser with Addition of Nanocomposites

Abstract The service life of components can be extended by repairing fatigue crack with laser so as to improve resource utilization rate. However, the effect of laser repair may be influenced by the instability of laser treatment. To investigate the addition of nanocomposites on the laser repairing effect, fatigue test under uniaxial tension was carried out to evaluate the fatigue life of precracked 304 stainless steel components repaired by laser. According to the results obtained from fatigue tests, a probabilistic fatigue life distribution model considered the sampling size and discreteness of data was established based on the three-parameter Weibull distribution model and three-parameter stress-life equation. The results of probabilistic fatigue life distribution model show that the fatigue life of components repaired by laser with addition of WC nanocomposites can be enhanced significantly, especially the high cycle fatigue life. Moreover, the microstructure of repaired region show that the WC nanoparticles could refine the recrystallized grains and lead to the improvement of strength and toughness of material around crack tip, which are the main reason of improved fatigue life. Meanwhile, smooth surface of repaired region caused by WC nanoparticles can also prevent the initiation of microcracks.

Manufacturing and Characterization of Zn-WC as Potential Biodegradable Material.

This work presents the manufacturing and characterization of zinc-tungsten carbide (Zn-WC) nanocomposite as a potential biodegradable material. A highly homogeneous WC nanoparticle dispersion in a Zn matrix was achieved by molten salt assisted stir casting followed with hot rolling. The Vickers microhardness and ultimate tensile strength of zinc were enhanced more than 50% and 87%, respectively, with the incorporation of up to 4.4 vol. % WC nanoparticles. Additionally, Zn-WC nanocomposite retained high ductility (> 65%). However, the electrical and thermal conductivities were reduced by 12% and 21%, respectively. The significant enhancement in mechanical strength makes nanoparticle-reinforced zinc a promising candidate material for biodegradable metallic implants for a wide range of clinical applications, including orthopaedic and cardiovascular implants as well as bioresorbable electronics.

Effect of Hot Rolling on Naval Brass/WC Nanocomposite

Abstract Metal matrix nanocomposite emerges as an important class of novel materials that can offer tunable mechanical, electrical, and thermophysical properties. With various types and volumes of nanoparticles in the metals, more design variables need to be considered for successful processing of these materials. In this paper, the hot rolling effect on Cu-40wt.% Zn alloy (naval brass) and its nanocomposite (with 10 vol.% WC) was studied at a suitable rolling temperature after a careful consideration of the complex phase composition and phase transition in the Cu-40 wt.% Zn. The rolling thickness reduction of 35% was applied. After the hot rolling, WC nanoparticles were distributed and dispersed more uniformly in the metal matrix. The microhardness of pure Cu-40 wt.% Zn after hot rolling was 179.42 HV while that of Cu-40 wt.% Zn with 10 vol.% of WC was enhanced to 230.10 HV. Electrical conductivity of the hot rolled samples were measured and the conductivity of the hot rolled nanocomposites was much higher than 1 MS/m, which is suitable for various applications that demand supreme mechanical properties and reasonable conductivities.

Design of Experiments Analysis of Friction Behavior of Mg-WC Nano-composites using Taguchi Methodology

Abstract Present study deals with the friction behavior of magnesium nano-composites reinforced with WC nano-particles in a pin-on-dosc tribotester. Different wt% of WC nano-particles of average particle size 80 nm is incorporated into molten magnesium by ultrasonic vibration assisted stir casting method. Taguchi methodology based on L27 orthogonal array is applied to minimize coefficient of friction (COF) by considering three process parameters viz. wt% of WC (A), applied load (B) and sliding speed (C). Analysis of variance (ANOVA) is done to find the significant process parameters and their respective percentage contribution on coefficient of friction. Applied load is found to be the most effective process parameter. Confirmation test is performed to validate the experimental result.

Wear performance of Mg-WC metal matrix nanocomposites using Taguchi methodology

Abstract Present study examines the effect of process parameters on wear behavior of magnesium nano-composites reinforced with WC nano-particles with the help of Taguchi methodology. Nanocomposites are developed by ultrasonic vibration assisted stir casting method. Three process parameters (wt% of WC, applied load and sliding speed) and three levels of each parameters are considered for this study. L27 orthogonal array is applied to minimize the wear rate of fabricated composites. Main effect and interaction effect of selected parameters are examined by main effect plot and interaction plot respectively. Analysis of variance is performed to find the significant parameters and their percentage of contribution. Sliding speed and wt% of WC are found to be the most significant parameters. Confirmation test is conducted to validate the experimental results. Finally SEM image of wear track is studied to find the wear mechanism.

WC strengthened W–Cu nanocomposite powder synthesized by in-situ reactions

A novel strategy to prepare W–Cu nanocomposite powder with WC nanoparticles for strengthening was proposed. The feasibility and mechanisms of the present in-situ reactions method for synthesizing multicomponent powders were demonstrated by both thermodynamic calculations and experiments. The W-Cu-WC nanopowder can be prepared at a low temperature with pure phase constitution and homogeneous microstructure with a mean particle size of 60 nm. Owing to in-situ reactions, the orientation relationship of WC and W is formed, which facilitates strong bonding between the strengthening particles and matrix. The new method is applicable to synthesize a variety of composite powders with tailorable phase and particle size.

TRIBOLOGICAL BEHAVIOR OF THIN NANO TUNGSTEN CARBIDE FILM DEPOSITED ON 316L STAINLESS STEEL SURFACE

This study presents the tribological behavior of austenitic 316L Stainless Steel (SS) coated with nano Tungsten Carbide (WC). The nano WC particles were prepared by mechano chemical method. The tungsten and toluene have been ball milled for 40[Formula: see text]h led to the synthesis of WC nano particles. An average particles size of 48[Formula: see text]nm was achieved. The prepared nano WC particles were deposited on 316L SS substrate as a thin film using DC magnetron sputtering process. The thickness of the nano WC coating was 5[Formula: see text][Formula: see text]m. The synthesized nano WC particles and the thin nano WC film are characterized using Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray Analysis (EDAX) technique. Vickers microhardness test was conducted to evaluate the microhardness of the thin film. A high microhardness value of 2242 HV[Formula: see text] was observed. The coated specimens are subjected to wear test using pin on disc setup and the tribological parameters such as friction and wear are analyzed. The results were compared with uncoated 316L SS specimen and micro WC particles coated 316L SS. The nano WC coated 316L SS possess high hardness and better wear resistance when compared with 316L SS and micro WC coated 316L SS specimen.

Influence of tungsten carbide (WC) nanoparticle on microstructure and mechanical properties of Cu/Sn57.6Bi0.4Ag/Cu solder joints

The effect of WC nanoparticles on the spreadability, microstructure and mechanical properties of Cu/Sn57.6Bi0.4Ag/Cu solder joints was investigated. The results showed that the spreadability of Sn57.6Bi0.4Ag composite solder was enhanced by WC nanoparticles, and the spreadability was increased first and decreased with increasing WC content next; when the content of WC was 0.1 wt%, the solder got relatively optimal spreadability. The dispersed WC particles provided the heterogeneous nucleation sites during the soldering process and led to the microstructure refinement of Sn57.6Bi0.4Ag solder alloy. WC particles restrained the growth rate of IMC by reducing the surface energy of Cu6Sn5, the shear strength of Sn57.6Bi0.4Ag–xWC/Cu (x = 0, 0.1) solder joints decreased seriously with increasing aging time, WC particles improved the shear strength and toughness of Sn57.6Bi0.4Ag/Cu solder joints by refining the microstructure.

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.

W2C-reinforced tungsten prepared using different precursors

Tungsten is considered to be the primary candidate material for high-heat-loaded structural parts in the DEMO demonstration fusion power plant. Its recrystallisation at high temperatures, which results in a loss of strength, can be suppressed by the incorporation of ceramic particles in the form of oxides or carbides. Here we propose the reinforcement of the W-matrix with W2C ceramic inclusions, which can be formed by a high-temperature reaction of the W-matrix with a carbide precursor. In this study the W2C particles were synthesised in-situ during vacuum sintering using three carbon sources: graphene, phenol-formaldehyde resin, and WC nanoparticles. Our results suggest that the WC nanoparticles are the most suitable carbon source for the formation of the W2C-W composite. The composite containing 24 wt% of W2C shows a denser structure and better mechanical properties compared to the pure tungsten. Additionally, ageing tests confirmed that the incorporation of W2C ceramic particles prevents the W-grain growth even at temperatures higher than 1200 °C.