Anion regulated the phase composition of tungsten carbide for efficient alkaline hydrogen evolution.

ABSTRACT This study examines the synergistic effects of plasma-assisted heating and ultrasonic vibration on the hard turning of 34CrNiMo6 steel, aiming to minimize tool flank wear. While cubic boron nitride (CBN) and tungsten carbide tools were evaluated, CBN demonstrated superior wear resistance, with statistical analysis confirming that the tool material was the most significant factor influencing wear. A hybrid machining approach was developed, integrating a plasma system for localized workpiece softening and ultrasonic vibration to reduce cutting forces through intermittent tool-workpiece contact. Using Taguchi-designed experiments, the optimal parameters for minimal flank wear were identified: CBN tools operating at reduced cutting conditions (0.50 mm depth of cut, 0.08 mm/rev feed, 40 m/min speed) combined with controlled plasma current (25 A) and maximum vibration amplitude (10 µm). Results revealed a dual-phase plasma current effect, initial force reduction followed by thermal wear at excessive current, and demonstrated that vibration amplitude significantly lowers wear.

ABSTRACT The YG8 tungsten carbide material is extensively utilized for its superior strength, hardness, and wear resistance, thereby placing greater demands on its drilling techniques. To address this, this study employs oxygen, which has a combustion-supporting effect, as the gaseous medium in near-dry electrical discharge drilling (N-EDD). By utilizing the exothermic chemical reaction between oxygen and steel under high temperature and pressure to release substantial chemical energy, efficient material removal is achieved, enabling high-efficiency drilling of YG8. Experimental results show that oxygen-assisted atomized discharge ablation drilling (OA-DAD), compared to air-assisted near-dry electrical discharge drilling (AN-EDD), improves the material removal rate (MRR) by 144.8%, increases the machining depth (De) of fixed-depth holes by 3.12%, reduces electrode wear rate (EWR) by 50.14%, and results in less residual core material. MRR shows an upward trend as rotational speed increases. To examine the main and interaction effects, along with their significance on various optimization criteria, an L27 (35) orthogonal array was employed. Furthermore, the optimal parameter combinations for each single-objective optimization were determined. Through parameter optimization experiments, an optimal MRR of 165.63 mg/min, a minimum overcut (OC) of 0.31 mm, and a machining hole with a depth deviation of −0.01 mm were achieved, verifying the accuracy of the optimal process parameter combinations for each indicator. Grey relational analysis was applied for multi-objective optimization of orthogonal experimental data, producing a hole exhibiting a MRR of 93.1 mg/min, OC of 0.67 mm, and De of 4.95 mm, thereby greatly enhancing both material removal efficiency and machining accuracy.

ABSTRACT Prominent applications of microslit-type geometries on molybdenum thin sheets include X-ray collimators and sustained discharge reactors. The parametric analysis of process variables affecting responses using a tungsten carbide micro-electrode during microdrilling and process optimization, the fabrication of microtools for machining microslits by considering the overcut at optimal conditions to attain the required slit width, and the machining of an array of slits using the fabricated microtool under the optimal conditions make up this research. Capacitance and voltage are the most influential process variables according to ANOVA. The process is optimized by overall evaluation criteria. The optimal condition when all responses are given equal weightages is obtained at capacitance = 100 pF, voltage = 80 V, feed rate (FR) = 10 µm/s, and tool rotational speed (TRS) = 2000 rpm. The average slit width at entrance and exit sides are measured to be 514.70 µm and 493.51 µm, respectively. The optimal condition by balancing machining efficiency and dimensional precision is found at capacitance = 10,000 pF, voltage = 200 V, FR = 40 µm/s, and TRS = 2800 rpm. The average slit widths at the entrance and exit sides are 506.72 µm and 478.02 µm, respectively, at that condition.

Abstract While maintenance, repair, and operations are crucial for improving the performance of gas turbine components, the properties of filler metal, such as Inconel alloys, may be insufficient in extremely harsh environments, necessitating the use of alternative materials need to be implemented. In this study, Alloy 625-based composites reinforced with varying WC (tungsten carbides) nanoparticles (1.25, 2.5, 3.75, or 5.0 wt pct) were fabricated via suction casting. The dendrites in both Alloy 625 and the WC-reinforced nanocomposites consisted of the γ matrix, and segregation of alloying elements in the interdendritic regions resulted in additional carbides and Laves phase precipitates were additionally observed. Synchrotron radiation experiments and microstructure investigations revealed that the partial dissolution of WC promoted the formation of Nb-rich MC and Mo, W-rich M 6 C carbides, while simultaneously reducing the volume fraction of Laves phase precipitates. Oxidation tests in steam (704 °C/1000 hours) showed that the Alloy 625 + WC nanocomposites exhibited slightly lower mass gain compared to the reference Alloy 625. In contrast, in the Ar + 0.25 pct SO 2 atmosphere, increasing WC content in Alloy 625 negatively affects the corrosion resistance due to the excessive formation of Ni 3 S 2 . The hardness of Alloy 625, initially measured at 201 HV10, increased to 254 HV10 with the addition of 5.0 pct WC, contributing to improved dry-sliding wear resistance.

ABSTRACT Natural fiber reinforced polymer composites are gaining prominence as sustainable, biodegradable alternatives in modern engineering. However, challenges like moisture absorption and poor thermal/electrical performance persist. Chemical fiber treatments can mitigate these issues. Among natural fibers, basalt stands out for superior mechanical properties, making basalt fiber-reinforced polymer (BFRP) composites increasingly vital. This study enhances BFRP performance by incorporating tungsten carbide (WC) ceramic nanofillers via hand layup fabrication. Mechanical and thermogravimetric analyses assessed composites with varying WC content (0–3 wt.%). Results showed deteriorating effect on tensile strength, while flexural strength, interlaminar shear, and impact resistance improved significantly at low nanofiller loadings (≤0.4 wt.%). Beyond this threshold, agglomeration is due to high surface energy limited gains. The specimens with nanofillers showed a notable improvement in wear resistance when compared to unfilled composites, although thermal stability was largely unaffected. SEM micrographs corroborated mechanical trends, confirming optimal dispersion at lower concentrations. These findings highlight WC’s potential to selectively enhance basalt fiber-reinforced polymer composites performance within strict compositional limits.

Diamond anvil cells are commonly used at synchrotron x-ray diffraction beamlines to study structural and thermoelastic properties of materials at high pressures. In a radial geometry, where the x-ray probe is oriented perpendicular to the axis of force, the deformation and strength of materials can be measured in situ. Because the anelastic and failure properties of materials depend strongly on temperature, many applications would benefit from the ability to measure high pressure radial diffraction in elevated and accurately controlled thermal environments. Previous work to introduce high temperature to radial diamond anvil cells has been largely limited to laser heating, with relatively scant efforts to resistively heat the sample. Here, we report a relatively straightforward adaptation of a simple wire coil heater, with in situ high-temperature radial diffraction performed on tungsten carbide up to 573K at beamline 12.2.2 of the Advanced Light Source. The results demonstrate that the differential stress supported by WC decreases with increasing temperature: the differential stress on the basal (001) and pyramidal (101) planes decreased 6.6% and 5.5%, respectively, while the (100) plane only saw a 2.7% decrease, in agreement with previous studies.

Tool Wear and temperature compensation in laser-assisted ultra-precision cutting of tungsten carbide aspheric molds

The primary goals of the investigation is to study the effects of a coating of TiAlN on tungsten carbide tool inserts using a high-velocity oxy-fuel thermal spraying technique; then, to machinize Inconel 925 alloys with these tools while incorporating Pongamia pinnata oil as a lubricant in a minimum quantity lubrication condition. Using this to create a core composite design model and find the real-world connections between the key machining process variables and the results. For the utilization response surface methods to optimizing the model, rank the parameters, and do sensitivity analysis. The critical aspect in this research is to assess the impact of changing critical machining process parameters on the quality of the machined job. This research focused on use scanning electron microscopy, X-ray diffraction, electron backscattering diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy to characterize the machined tool inserts and Inconel 925 materials.

Purpose: This study aimed to evaluate the effects of different types of finishing and/or polishing protocols on the surface roughness of two different restorative materials that are frequently preferred in pediatric dentistry. Materials and Methods: Compomer (Dyract XP) (n=20) and glass hybrid restorative (Equia Forte HT) material discs (n=20) were prepared using metal moulds and initial surface roughness values (Ra) were measured and recorded with a profilometer. Each restorative material was subdivided to 4 groups (n=5) containing different finishing and/or polishing protocols for each restorative material group (Sof-Lex Disc, Sof-Lex Disc+Rubber Bur, Tungsten Carbide Bur and Tungsten Carbide Bur+Rubber Bur). After finishing&polishing procedures, final surface roughness measurements were performed and recorded. Kruskal Wallis-H and Wilcoxon Signed-Rank tests were used to analyze the data. Statistical significance value was taken as 0.05. Results: According to analyzes performed considering the alteration (ΔRa) between initial and final surface roughness values, no statistically significant difference was found in terms of ΔRa between two restorative materials and their subgroups (p=0.055). Also, final roughness values of compomer samples that were subjected to Tungsten Carbide Bur and Tungsten Carbide Bur+Rubber Bur were found to be significantly higher than initial roughness (p=0.043 and p=0.043, respectively). Conclusions: It was concluded that finishing and polishing protocols caused similar roughness changes on compomer and glass hybrid restorative material surfaces. However, it was also concluded that compomer surface finished with Tungsten Carbide burs was rougher than initial values.

Abstract Broadband photodetectors with high responsivity and low dark current are crucial for advancing applications in optoelectronics, infrared imaging, and environmental sensing. In this work, we report a Tungsten Carbide/n type Silicon (WC/n-Si) hybrid photodetector that demonstrates high responsivity (31.03 A/W at 405 nm) and a broad spectral response from 280 nm to 3286 nm. A tungsten carbide layer was deposited onto an n-doped silicon substrate using sputtering, creating a heterostructure that utilizes the complementary absorption properties of WC and Si. Despite the amorphous nature of WC, the structure delivers significant mid-infrared detection, with responsivity values of 7.66 A/W at 2700 nm and 0.5 A/W at 3286 nm. We further analyzed the device's performance through absorption simulations, response time characterization, and benchmarking against state-of-the-art photodetectors, including 2D/TMD (Transition Metal Dichalcogenides) based devices. This simple, scalable device combines simulation and experiment to show strong mid-IR sensitivity and potential for low-cost broadband photonics.

Abstract Machining Inconel 718 remains challenging due to its high strength and low thermal conductivity, necessitating advanced tool modifications, such as cryogenic treatment and surface texturing, to enhance tool life and performance. The present study investigates the synergistic effect of cryogenic treatment and laser-induced surface texturing on uncoated tungsten carbide (WC) inserts during the turning of Inconel 718 under dry machining. The experiments evaluated four tool configurations—untreated (UT), cryogenically treated (CT), untreated textured (UTT), and cryogenically treated textured (CTT) under a constant depth of cut (0.4 mm) with cutting speeds of 30, 60, and 90 m/min and feed rates of 0.08, 0.12, and 0.16 mm/rev in turning operation. Key performance parameters were analyzed, including flank wear, roundness deviation, cutting temperature, surface roughness, chip morphology, and subsurface hardness. Compared to untreated tools, cryogenically treated and textured inserts reduced flank wear by up to 70%, indicating superior wear resistance and stability during dry machining of Inconel 718. Surface roughness remained under 0.8 µm, and roundness errors were significantly minimized. Microhardness profiles of CTT-machined samples exhibited a uniform subsurface hardness gradient, characterized by reduced work hardening, thereby preserving structural integrity. SEM analysis confirmed enhanced η-phase carbide precipitation and densification of the cobalt binder in cryogenically treated tools, resulting in ~8% improvement in hardness and a reduction in wear tendency. Uniform chip segmentation and improved chip control with CTT tools demonstrate effective thermal regulation and optimized tribological behavior. Integrating cryogenic treatment and surface texturing presents an efficient and sustainable solution for machining nickel-based superalloys.

Coupling biomass valorization with rechargeable metal-air batteries offers a promising strategy to address energy storage and sustainable synthesis challenges. However, it demands highly active bifunctional catalysts capable of replacing the sluggish oxygen evolution reaction (OER) with value-added biomass electrooxidation. We report here a single-atom nickel-decorated tungsten carbide (Ni-WC x ) catalyst that demonstrates exceptional bifunctional activity for both the oxidation of 5-hydroxymethylfurfural (HMF) and the oxygen reduction reaction (ORR). The catalyst achieves near-quantitative conversion of HMF to furandicarboxylic acid (FDCA) with 99% selectivity and shows excellent ORR performance, featuring a half-wave potential (E 1/2) of 0.855 V. Through in situ spectroscopic analysis and multiscale simulations, we reveal a dual role of the atomically dispersed Ni δ+ sites: serving as intrinsic active centers and reconstructing the interfacial hydrogen-bond network to facilitate mass transport of bulky HMF molecules. When applied in an HMF-assisted Zn-air battery, the catalyst enables an ultralow charge-discharge voltage gap of 0.71 V at 20 mA cm-2 and remarkable cycling stability. This work proposes a new design strategy for electrocatalysts, emphasizing interfacial solvent engineering as a critical route to advanced hybrid energy-chemical systems.

Abstract This article investigates the impact of second‐phase additives on the structure and mechanical properties of zirconium diboride (ZrB 2 )‐based ceramic materials. The materials obtained were characterized by X‐ray diffraction, scanning electron microscopy, and Vickers hardness (HV) analysis. As a result, in the temperature range of 1800–2000°C, dense ceramic materials with a fine‐grained structure and uniform distribution of secondary phases were obtained. Additives such as molybdenum disilicide (MoSi 2 ), silicon carbide (SiC), molybdenum carbide (Mo 2 C), and tungsten carbide (WC) lowered the sintering temperature compared to the sintering of pure ZrB 2 . HV measured at loads from 1 to 20 kg showed a weak dependence of hardness on the load. Maximum hardness values were achieved for the three‐component ceramics ZB 2 + 15 vol.% SiC + 5 vol.% Mo 2 C and ZB 2 + 15 vol.% SiC + 5 vol.% WC (HV 20 = 18.68 GPa and 19.33 GPa, respectively) due to increased density of the materials and small grain sizes. The addition of 15 vol.% MoSi 2 leads to an increase in the fracture toughness (5.04 MPa*m 1/2 ) and grain boundary strength (0.58 GPa). This points to the formation of grain boundary states with increased strength (σ f = 0.48 GPa).

Spark plasma sintering (SPS) is one of the new methods in powder metallurgy which has made significant progress over the past two decades and has attracted plenty of attention from researchers and industries. Recently, given the high capabilities of the SPS method, its use for manufacturing functional materials (FGM) has also sparked great research interest. Considering the studies conducted and the limitations of tungsten alloys as well as tungsten carbide alone in applications such as high-energy penetrants in the oil and gas industries along with friction stir welding tools, W/WC FGM samples have been manufactured using the SPS method for the first time in this study to enhance mechanical properties. The aim of this study is to examine the effect of the factors of pressure and time of SPS sintering on the microstructural properties of W/WC FGM. The phase, elemental, and structural properties of the powder, cross-sectional area, and fracture surface of the SPS samples, after the experiments, were characterized using X-ray diffraction and scanning electron microscopy images. The results revealed that the best sintering conditions for creating W/WC FGM bulk with the best mechanical properties included sintering the sample for 15min, a pressure of 60MPa, a temperature of 1400°C, and a heating rate of 200°C/min. In the optimal case, the W/WC FGM sample consisted of five layers with different chemical compositions and a microstructure without a diffusion zone, with tensile and flexural strengths of 745 and 890MPa, respectively, and a density of 92.5%.

Abstract This study pioneers the optimization of Friction Stir Welding (FSW) for C71500 copper-nickel alloys, delivering significant enhancements in weld quality and corrosion resistance while bridging a critical gap in integrated mechanical, microstructural, and corrosion analyses essential for demanding marine and offshore applications. A robust tungsten carbide tool was employed on a vertical milling machine with refined parameters (1130 rpm rotational speed, 30 mm/min traverse speed, 5 KN axial force) which yielded defect-free welds with unprecedented performance. The evaluated mechanical properties, demonstrated superior retention of around 90% of the tensile strength (342 MPa after welding vs. 380 MPa before welding). The Vickers hardness tester showed a value between 198–262 HV, indicating profound grain refinement. Microstructural assessments per ASTM E112 confirmed dynamic recrystallization, reducing weld zone grain size to 12.4 µm from the parent metal's 35.2 µm, enhancing the structural integrity. ASTM G48 corrosion testing of the specimen in 6% FeCl3 revealed negligible weight loss (0.5566 g) and zero pitting, surpassing conventional welds by up to 75%. The corrosion rate was calculated using the Tafel extrapolation curves and was found to be 1260 mpy. Further the Taguchi optimization revealed the highest S/N ratio for spindle rotation, i.e. 1350 rpm and H13 tool material demonstrated the highest corrosion resistance among all. These results establish FSW's dominance in preserving alloy properties and enabling cost-effective solutions in harsh marine environments and high-stake industries.

This study presents an experimental investigation into the efficiency of ultranet cracking technology for processing heavy crude oil fractions. A high-pressure hydrodynamic system equipped with tungsten carbide nozzles and rotating targets was employed to generate compact liquid jets with velocities ranging from 400 to 750 m/s. The experiments evaluated the effects of jet velocity, impact angle, and target material on the breakdown of long-chain hydrocarbons. Results demonstrated that at a jet velocity of 600 m/s and an impact angle of 80°, the yield of light fractions with boiling points below 350°C increased to 28.4%, exceeding the untreated oil baseline by approximately 9–12%. Additionally, viscosity was reduced from 220 to 145 mPa·s after two treatment cycles, indicating significant molecular degradation. The introduction of cyclic flow regimes and turbulence promoters further enhanced the performance, increasing the light fraction yield by up to 4% and 2–3%, respectively. Calculated deceleration forces reached up to 1.6×10⁶ m/s², emphasising the intense mechanical impact driving the cracking process. The findings highlight ultranet cracking as an energy-efficient and adaptable method for upgrading heavy petroleum feedstocks. Compared with ultrasonic cavitation under comparable specific energy inputs (≈500–700 kJ·kg⁻¹), ultranet cracking achieved higher light-cut yields (28.4%–31.2% vs. ~21–23%), highlighting its performance advantage in partial upgrading.

Hydrocracking is a promising route for the chemical recycling of polyolefins (PO), converting them into short hydrocarbons over bifunctional catalysts with metal sites for hydrogenation and dehydrogenation, and Brønsted acid sites (BAS) for isomerization and C-C bond cleavage. However, PO feedstocks containing polyvinyl chloride (PVC) can release chlorine (Cl) under reaction conditions, deactivating conventional noble metal/zeolite catalysts. Moreover, the lack of site intimacy and the presence of micropores within conventional catalysts create challenges around the transport of high-molecular-weight, sterically encumbered polymer intermediates. Here, we report tungsten carbides (WxC) as a novel type of bifunctional catalysts that address these challenges. W/W2C phases on WxC offer "metal" sites, and -OH on WOx species introduces BAS in close proximity. The "metal":BAS ratio can be tuned through carburization temperature, leading to a volcano-shaped activity trend reflecting the requirement for metal-BAS balance. Kinetic data demonstrate that each PO chain undergoes sequential cleavage, while trends in cracking ideality and selectivity follow those in short-alkane hydrocracking. On the per-BAS basis, WxC is more efficient than conventional bifunctional catalysts by more than an order of magnitude, due to enhanced polymer transport. They maintain or show increased activity with 10 wt % PVC in the substrate. This work establishes transition-metal carbides as earth-abundant bifunctional catalysts with unique site proximity and heteroatom compatibility. These features, along with the broad structure space for rational tuning, make them promising options to tackle specific challenges that polymer feedstocks present in hydrocracking.

This study investigates the optimization of coating powder composition for enhanced microhardness and reduced porosity. Using an I-optimal design approach, the research explores the effects of varying weight percentages of Tungsten Carbide (WC), Nickel-Chrome-Boron (Ni-Cr-B), Aluminum (Al), and Cobalt (Co) on coating properties. The experimental design matrix consisted of 16 trials, including four replicated experiments. Response surface methodology and ANOVA were employed to analyze the relationship between formulation factors and responses. Results indicate that WC content positively correlates with microhardness, while Al content increases porosity. The optimal coating composition was determined to be 65% WC, 25% Ni-Cr-B, 5% Al, and 5% Co, achieving a desirability value of 0.881. This study provides insights into the complex interactions between coating components and their impact on critical properties, offering a foundation for developing high-performance coatings with enhanced resistance to oxidation, corrosion, and erosion for various industrial applications.

HighlightsWhat are the main findings?PDC coating reduced erosion depth by 77.6% compared with WC.Valve lifetime extended by about 4.5 times under slurry flow.Erosion concentrated near gate–seat interface areas.What are the implications of the main findings?PDC coating improves durability of subsea gate valves.Lower wear reduces maintenance and downtime costs.Supports material selection for erosion-critical valve designs.Produced well flow is controlled through valves placed in the Christmas tree. Being mostly gate-type valves, they isolate the well from the surface when commanded or automatically in an emergency. The reliability of these valves is essential for subsea wells, as maintenance and replacement involve high cost, time, and HSE risks. Their design must withstand harsh conditions such as high temperature, pressure, solid particles, and corrosive environments. However, failures caused by leakage, cold welding, and the erosion of sealing elements are still common. These issues motivated the initial stage of this research, which experimentally showed that replacing the current tungsten carbide (WC) coating with polycrystalline diamond compact (PDC) material reduces friction and wear due to its high hardness and thermal stability. Based on these results, a 3D subsea gate valve model was developed and simulated in Ansys Fluent 2024 R2 under API slurry test conditions using the Oka erosion and Discrete Phase Models. A comparative analysis of WC and PDC coatings for a 5-inch gate valve exposed to a 2% sand slurry (250–400 μm) showed that PDC reduces the erosion depth by 77.6% and extends the valve lifetime by 4.5 times. The findings support the use of PDC for improved erosion resistance in subsea valve applications.