Search Results (212)

To investigate the effect of liquid-phase laser ablation on the hardness of WC-Co cemented carbide, this study performed hardness testing, elemental distribution analysis, and XRD phase analysis. The influence of ablation times on the hardness, elemental distribution, and phase composition of WC-Co cemented carbide was examined, and a model describing the hardness evolution mechanism under liquid-phase laser ablation was proposed. The results demonstrated that the hardness of WC-Co cemented carbide increased with the number of ablations. After 14 ablation times, the maximum hardness reached 2800 HV, representing an increase of 51%–56% compared to the matrix hardness. As the number of ablations increased, the content of ditungsten carbide (W₂C) and tungsten carbide (WC) in the cemented carbide increased, the WC grain size decreased, the dislocation density increased, and the distribution became more uniform. The refinement of WC grains and the elevated dislocation density facilitated stronger intergranular bonding, thereby significantly enhancing the material’s hardness. This study provides theoretical guidance for improving the surface mechanical properties of WC-Co cemented carbide tools through liquid-phase laser ablation. Full article

This study proposes a laser texturing method to optimize adhesion and minimize residual stresses in CVD diamond films deposited on tungsten carbide (WC-Co). WC-5.8 wt% Co substrates were textured with quadrangular pyramidal patterns (35 µm) using a 1064 nm nanosecond-pulsed laser, followed by chemical treatment (Murakami’s solution + aqua regia) to remove surface cobalt. Diamond films were grown via HFCVD and characterized by Raman spectroscopy, EDS, and Rockwell indentation. The results demonstrate that pyramidal texturing increased the surface area by a factor of 58, promoting effective mechanical interlocking and reducing compressive stresses to −1.4 GPa. Indentation tests revealed suppression of interfacial cracks, with propagation paths deflected toward textured regions. The pyramidal geometry exhibited superior cutting post-deposition cooling time for stress relief from 3 to 1 h. These findings highlight the potential of laser texturing for high-performance machining tool applications. Full article

To elucidate the key material parameters governing the tribological performance of ceramic composites under dry sliding against steel, this study presents a comprehensive comparative assessment of the microstructural characteristics, mechanical performance, and tribological behavior of two alumina–zirconia (Al₂O₃–ZrO₂) ceramic composites, each reinforced with a 42 vol.% carbide phase: zirconium carbide (ZrC) and tungsten carbide (WC). Specifically, tungsten carbide (WC) was selected for its exceptional bulk mechanical properties, while zirconium carbide (ZrC) was chosen to contrast its potentially different interfacial reactivity against a steel counterface. ZrC and WC were selected as reinforcing phases due to their high hardness and distinct chemical and interfacial properties, which were expected to critically affect the wear and friction behavior of the composites under demanding conditions. Specimens were consolidated via spark plasma sintering (SPS). The investigation encompassed macro- and nanoscale hardness measurements (Vickers hardness HV₁, HV₁₀; nanoindentation hardness H), elastic modulus (E), fracture toughness (K_IC), coefficient of friction (COF), and specific wear rate (W_s) under unlubricated reciprocating sliding against 100Cr6 steel at normal loads of 10 N and 25 N. The Al₂O₃–ZrO₂–WC composite exhibited an ultrafine-grained microstructure and markedly enhanced mechanical properties (HV₁₀ ≈ 20.9 GPa; H ≈ 33.6 GPa; K_IC ≈ 4.7 MPa·m^½) relative to the coarse-grained Al₂O₃–ZrO₂–ZrC counterpart (HV₁₀ ≈ 16.6 GPa; H ≈ 27.0 GPa; K_IC ≈ 3.2 MPa·m^½). Paradoxically, the ZrC-reinforced composite demonstrated superior tribological performance, with a low and load-independent specific wear rate (W_s ≈ 1.2 × 10⁻⁹ mm³/Nm) and a stable steady-state COF of approximately 0.46. Conversely, the WC-reinforced system exhibited significantly elevated wear volumes—particularly under the 25 N regime—and a higher, more fluctuating COF. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX) of the wear tracks revealed the formation of a continuous, iron-enriched tribofilm on the ZrC composite, derived from counterface material transfer, whereas the WC composite surface displayed only sparse tribofilm development. These findings underscore that, in steel-paired tribological applications of Al₂O₃–ZrO₂–based composites, the efficacy of interfacial tribolayer generation can supersede intrinsic bulk mechanical attributes as the dominant factor governing wear resistance. Full article

In this study, we investigated the electrochemical corrosion behavior and mechanisms of FeCrNi/WC alloys with varying contents of CTC-S (spherical WC) and CTC-A (angular WC) in a 3.5 wt.% NaCl solution, addressing the corrosion resistance requirements for stainless steel composites in marine environments. The electrochemical test results demonstrate that the corrosion resistance of the alloy initially increases with the CTC-A content, followed by a decrease, which is associated with the formation, stability, and rupture of the passivated film. Nyquist and Bode diagrams for electrochemical impedance spectroscopy confirm that the charge transfer resistance of the passivated film is the primary determinant of the composite’s corrosion performance. A modest increase in CTC-A contributes to the formation of a more heterogeneous second phase, providing a physical barrier and enhancing solid solution strengthening, and thus delaying the cracking and corrosion processes of the passivation film. However, excessive CTC-A content leads to significant dissolution of the alloy’s reinforcement phase and promotes decarburization, resulting in the formation of corrosion pits, craters, and cracks that compromise the passivation film and expose fresh alloy surfaces to further corrosion. When the CTC-A content is 10% and the CTC-S content is 30%, this combination results in minimal degradation in the corrosion performance (0.213 μA·cm²) while balancing the hardness and toughness of the alloy. Additionally, electrochemical evaluations reveal that incorporating angular CTC-A particles at 10 vol% effectively delays the breakdown of the passivation film by mitigating the interfacial galvanic coupling through enhancing the mechanical interlocking at the WC/FeCrNi interface. The CTC-A/CTC-S hybrid system exhibits a remarkable 62% reduction in the pitting propagation rate compared to composites reinforced solely with spherical WC, which is attributed to the preferential dissolution of angular WC protrusions that sacrificially suppress crack initiation at the phase boundaries. Full article

Thermally sprayed carbide cermet coatings, particularly those based on tungsten carbide (WC) and chromium carbide (Cr₃C₂) and produced with the high velocity oxygen fuel (HVOF) process, are used in tribological applications as environmentally friendly alternatives to electroplated hard chrome coatings. These functional coatings are especially prevalent in the automotive industry, offering excellent wear resistance. However, their mechanical and tribological performances are highly dependent on factors such as feedstock powders, spray parameters, and service conditions. This review aims to gain deeper insights into the above elements. It also outlines emerging advancements in HVOF technology—including in situ powder mixing, laser treatment, artificial intelligence integration, and the use of novel materials such as rare earth elements or transition metals—which can further enhance coating performance and broaden their applications to sectors such as the aerospace and hydro-machinery industries. Finally, this literature review focuses on process optimization and sustainability, including environmental and health impacts, critical material use, and operational limitations. It uses a life cycle assessment (LCA) as a tool for evaluating ecological performance and addresses current challenges such as exposure risks, process control constraints, and the push toward safer, more sustainable alternatives to traditional WC and Cr₃C₂ cermet coatings. Full article

The anodic stability of tungsten carbide (WC) and iron oxide with a spinel structure (Fe₃O₄) were compared against similar data for nanostructured, boron-doped diamond (BDD), and the benchmark Vulcan XC72 carbon, in view of their eventual application as alternative supports for the anion exchange membrane electrolyzer anode. To this end, metal oxide composites were prepared by the in situ autocombustion (ISAC) method, and the anodic behavior of materials (composites as well as supports alone) was investigated in 1 M NaOH electrolyte by the rotating ring–disc electrode method, which enables the separation oxygen evolution reaction and materials’ degradation currents. Among all supports, BDD has proven to be the most stable, while Vulcan XC72 is the least stable under the anodic polarization, with Fe₃O₄ and WC demonstrating intermediate behavior. The Co₃O₄-BDD, -Fe₃O₄, -WC, and -Vulcan composites prepared by the ISAC method were then tested as catalysts of the oxygen evolution reaction. The Co₃O₄-BDD and Co₃O₄-Fe₃O₄ composites appear to be competitive electrocatalysts for the OER in alkaline medium, showing activity comparable to the literature and higher support stability towards oxidation, either in cyclic voltammetry or chronoamperometry stability tests. On the contrary, WC- and Vulcan-based composites are prone to degradation. Full article

This study develops novel superhydrophobic UHMWPE/PTFE/PVA composites via hot-pressing sintering to achieve ultra-low friction and enhanced wear resistance. The ternary system synergistically combines UHMWPE’s mechanical stability, PTFE’s lubricity, and PVA’s dispersion/binding capability. Results show PTFE disrupts UHMWPE crystallization, reducing melting temperature by 2.77 °C and enabling energy dissipation. All composites exhibit hydrophobicity, with optimal formulations (UPP3/UPP4) reaching superhydrophobicity. Tribological testing under varied loads and frequencies reveals low friction, where UPP1 achieves a COF of 0.043 and wear rate below 1.5 × 10⁻⁵ mm³/(N·m) under low-load conditions. UHMWPE oxidative degradation forming carboxylic acids at the interface (C=O at 289 eV, C–O at 286 eV). Formation of tungsten oxides (WO₃/WO₂), carbides (WC), and transfer films on steel counterparts. A four-step tribochemical reaction pathway is established. PVA promotes uniform transfer films, while PTFE lamellar peeling and UHMWPE chain stability enable sustained lubrication. Carbon-rich stratified accumulations under high-load/speed increase COF via abrasive effects. The composites demonstrate exceptional biocompatibility and provide a scalable solution for biomedical and industrial tribological applications. Full article

Conventional WC-Co hard metals have proven to be difficult to manufacture by means of laser powder bed fusion (PBF-LB), resulting in residual pores, crack formation, foreign phase formation, and the inhomogeneous growth of the carbide phase. Alternative compositions such as the W-C-Ti system presented in this study need to be investigated. Through the employment of a high-throughput screening approach, 11 alloy compositions were investigated to determine the influence of the carbon content and tungsten–titanium ratios on microstructure formation and basic mechanical properties. Two screenings were conducted, with one varying the carbon content (10–35 at.%) and the other adjusting the W/Ti ratios (10:90 to 60:40 at.%). Microstructural analyses using scanning electron microscopy (SEM), X-ray diffraction (XRD), and hardness measurements provided insights into phase formation, grain distribution, and mechanical properties. The results showed that increasing the carbon content significantly enhanced the hardness (from 681 HV (10 at.% C) to 1898 HV (35 at.% C)) due to higher δ-(Ti,W)C_1−x carbide phase fractions. Alloys with a higher tungsten content exhibited finer microstructures and an improved crack resistance while maintaining a high hardness (1900–2100 HV). This study identified an alloy with 32.5 at.% W, 32.5 at.% Ti, and 35 at.% C as a promising candidate for further investigation, with properties similar to those of a conventional WC-Co hard metal. Full article

In the “dual carbon” objective, the preparation of non-precious metal catalysts with low cost and high activity is essential for the study of hydrogen evolution reactions (HERs). This study employed biomass pomelo peel powder as the carbon source and ammonium metatungstate (AMT) as the tungsten source and, through a facile one-step method in molten salt, fabricated a biomass carbon-based nanocatalyst featuring carbon flakes adorned with tungsten carbide (WC) nanoparticles. Dicyandiamide and cysteine were introduced as nitrogen and sulfur sources, respectively, to explore the impacts of N-S elemental doping on the structure, composition, and HER performance of the WC/C catalyst. The experimental results showed that N-S doping changed the electronic structure of WC and increased the electrochemically active surface area, resulting in a significant increase in the HER activity of WC/C@N-S catalysts. The WC/C@N-S catalyst was evaluated with hydrogen evolution performance in a 0.5 mol/L H₂SO₄ solution. When the cathodic current density reached 10 mA/cm², the overpotential was 158 mV, and the Tafel slope was 68 mV/dec, underscoring its excellent HER performance. The outcomes offer novel insights into the high-value utilization of agricultural biomass resources, and pave the way for the development of cost-effective, innovative hydrogen evolution catalysts. Full article

Due to the low hardness of carbon steels, their low resistance to wear, and erosion by cavitation and corrosion, it is necessary to protect the surfaces of parts with layers capable of ensuring the properties listed above. In this paper, we started from the premise that adding tungsten carbide (WC) powders during the electric arc spraying process of stainless steel would lead to obtaining a composite material coating resistant to wear and erosion at high temperatures, with relatively lower manufacturing costs. Thus, our research compared the following two types of coatings: a highly alloyed layer with WC, Cr, and TiC (obtained from 97MXC core wires) and a 60T/WC coating (obtained from a 60T solid-section wire to which WC was added), in terms of microstructure, mechanical properties, dry friction wear, and behaviour at erosion by cavitation (EC). The results of our research demonstrated that although the 60T/WC coating had lower erosion by cavitation behaviour than the 97MXC one, it can still be considered as a relatively good and inexpensive solution for protecting C15 steel parts. Full article

In recent years, the field of bionic engineering has advanced at a remarkable pace. Numerous engineering challenges have been addressed through inspiration drawn from biological organisms in nature. In this paper, laser cladding was employed to fabricate a bionic unit inspired by the radial ribs of the bivalve shell surface morphology on 20CrMnTi steel, with the aim of enhancing its wear performance. The metallic powder used in the experiments was prepared by blending Ni60 alloy powder with tungsten carbide (WC) in a predetermined ratio. The WC content was maintained within a mass percentage range of 15% to 60% in the composite powder system. The microstructure and properties of the bionic unit were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and a hardness tester, while its dry sliding wear resistance was evaluated using a block-on-ring tribometer. The influence of the WC content on the microstructure, hardness, surface roughness, and wear performance of the bionic unit was investigated. The experimental results revealed that the bionic unit exhibited a dual microstructure comprising equiaxed crystals and fine dendritic structures. The incorporation of WC induced pronounced grain refinement, while the dispersed WC particles formed effective metallurgical bonding with the Ni-substrate. A positive correlation was observed between the WC content and hardness, with peak hardness reaching 1008 HV_0.2 at 60% WC. Tribological analysis demonstrated a wear mechanism transition from dominant abrasive wear to a hybrid abrasive–adhesive wear. The wear volume of the bionic unit decreased with increasing WC content, and the extent of damage was reduced. Full article

Laser alloying was used to form metal matrix composite layers strengthened by WC particles. The process parameters were selected in such a way that there was no complete melting of the WC particles. Four different laser beam powers (from 0.65 kW to 1.3 kW) were used, generating different temperature distributions during processing. The temperature across the laser track axis was determined according to the mathematical model proposed by Ashby and Esterling. All layers produced contained unmelted WC particles in an aluminum-based matrix. The depth of the WC-Al composite layers strongly depended on the applied laser beam power. The lowest thickness of 198 ± 36 µm was measured for the layer produced at a laser beam power of 0.65 kW. A twofold increase in power P was the reason for obtaining a thickness th_AZ = 387 ± 21 µm. The power of the laser beam also affected the percentage of the substrate material (7075 alloy) in the molten pool during the laser processing. As a result, the highest amount of substrate material was obtained for the WC-Al composite layer produced using the highest laser beam power P = 1.3 kW. Simultaneously, this layer was characterized by the lowest percentage of tungsten carbide particles in this layer. The temperature profile along the axis of the laser track and also the maximum temperature reached confirmed the difference in the bonding between the reinforcing WC particles and the metal matrix. For P = 0.65 kW, too low a temperature was reached for the tungsten carbide particles to overmelt, resulting in poor bonding to the metallic matrix in the layer. Moreover, the layer showed serious defects such as discontinuity, porosity, and cracks. As a result, the WC-Al composite layer produced at the lowest laser beam power was characterized by a wear resistance lower (I_mw = 6.094 mg/cm²/h) than the 7075 alloy without surface layer (I_mw = 5.288 mg/cm²). The highest wear resistance was characteristic of the 7075 alloy laser alloyed with a laser beam power equal to 1.17 kW (I_mw = 2.475 mg/cm²/h). This layer showed satisfactory quality and adhesion to the substrate material. Full article

This work investigates the effect of the addition of tungsten carbide (WC) particles as reinforcements to Ni (Inconel 625) versus Co (Stellite 6) alloys during deposition by laser cladding to form wear-resistant metal matrix composite (MMC) coatings. While the related literature often associates the presence of WC with the enhanced wear performance of MMC coatings, this work shows that such an effect is not universal as it may critically depend on the metallic matrix employed. Thus, to demonstrate whether the reinforcement and matrix act synergically in such a scenario or not, MMC coatings formed by Inconel 625 and Stellite 6, both with WC content ranging from 10% to 40%, were deposited under the same laser cladding setup on AISI 304 stainless steel substrates, being WC-free samples produced together for comparison basis. As expected, the hardness levels increased with more WC presence in both matrices, but the wear resistance was specifically evaluated by means of the metal wheel abrasion test (ASTM B611). The results revealed that the use of WC as a reinforcement indeed affects the matrix materials differently; for Stellite 6, the wear resistance increased with up to 20% of WC (in contrast to the hardness indication), whereas for Inconel 625, the wear resistance progressively decreased with more WC content. It was observed via scanning electron microscopy (SEM) that the WC particles within the Inconel 625 alloy tended to intensive cracking, being in this way more prone to detach from the matrix and hence representing a weakening factor for the effectiveness of the coatings produced. Thus, it is concluded that the addition of WC particles, as potential reinforcements for MMC coatings, is not always effective (synergic with the matrix) in providing wear resistance, hence, opposing the prevailing consensus. This outcome and its reasons will certainly help with insights into proper design of MMC coatings, starting with the importance of matrix material selection. Full article

Pulsed lasers have a wide range of applications in scientific and industrial fields, and the saturable absorber (SA) is the core device of pulsed lasers. Tungsten carbide (WC) has garnered significant attention due to its exceptional physicochemical properties, making it a promising candidate for optoelectronic applications, particularly as an SA in pulse lasers. This study is the first to report the nonlinear optical properties of WC thin film at a 1064 nm wavelength and its use as an SA device to generate pulsed lasers. A high damage threshold of 472.4 mJ/cm² was achieved, which is a critical parameter for high-power laser applications. The constructed laser demonstrated pulsed output with a central wavelength of 1064.12 nm, an average output power of 185 mW, and a narrow pulse width of 684 ns. Our research has provided a strong candidate for the development of future economically stable high-power laser systems. Full article

Q235B is widely used in marine engineering materials; however, its wear resistance and corrosion resistance are poor. To improve wear and corrosion resistance, a CoCrFeNi high-entropy alloy (HEA) composite coating was cladded using laser cladding (LC) technology. Different proportions of tungsten carbide (WC) and Nb elements were added to the CoCrFeNi HEA coating, and the microstructure, phase, hardness, wear, and corrosion resistance of three different composite coatings were analyzed. The results show that the in situ synthetic phase is composed of Face central cubic (FCC) (Cr₃C₂) and strengthening phases such as W, WC, and NbC. In the process of LC, Nb will react with WC in situ, which not only reduces the morphology of the CoCrFeNi HEA cladding coating changed by adding WC, but also generates NbC, which leads to the dissolution of WC particles and improves the uniformity of particle distribution of the coating. The hardness of the coating with Nb is increased by 1.40 times, the wear resistance is enhanced, and the peeling of the hard phase is reduced during wear. The corrosion resistance of the coating with only WC particles is the best. Nb reduces the morphology of CoCrFeNi HEA cladding coating changed by WC particles. Although the coating with Nb is not as strong as that with WC particles only, it has outstanding hardness and wear resistance. Full article