Search Results (3,694)

The growing demand for sustainable materials in construction and sanitation has increased interest in natural fibre-reinforced polymer composites. Rice husk, an abundant agricultural by-product, offers a promising alternative as a reinforcing filler in polypropylene (PP) composites. This study aims to assess the suitability of PP composites reinforced with micronised rice husk particles for application in sanitary components. Two formulations containing 20% and 30% rice husk were developed and characterised. Comprehensive analysis included morphological, thermal, rheological, mechanical, hygroscopic, and tribological testing. Results showed that particles incorporation enhanced thermal stability and crystallinity due to a nucleating effect, with the 30% composite showing higher crystallinity. Thermogravimetric analysis showed that although the T₅% decreased from 374.1 °C for neat PP to 309.2 °C and 296.2 °C for the 20% and 30% composites, respectively, the DTG peak temperatures increased by 15.9 °C and 17.6 °C, indicating a delayed main decomposition stage of PP matrix and enhanced overall thermal stability. Rheological behaviour revealed increased viscosity and pseudoplasticity at higher particle content Mechanical characterisation showed an increase in Young’s modulus from 1021 MPa for neat PP to 1065 MPa (+4%) and 1125 MPa (+10%) for PP_Rice_20% and PP_Rice_30%, respectively. In contrast, the nominal strain at break dropped sharply from 238% (PP) to 30% (PP_Rice_20%) and 16% (PP_Rice_30%). Shrinkage decreased from 1.31% (PP) to approximately 1.05% in both composites, indicating improved dimensional stability. However, water absorption rose from 0.015% (PP) to 0.111% (PP_Rice_20%) and 0.144% (PP_Rice_30%), accompanied by an increase in surface roughness (Sa from 0.34 µm to 0.78 µm and 1.06 µm, respectively). The composite with 20% rice husk demonstrated better filler dispersion, reduced water uptake, and smoother surfaces, making it more suitable for injection-moulded components intended for use in humid environments. Overall, the study supports the use of agricultural residues in high-performance biocomposites, contributing to circular economy strategies and the development of more sustainable polymer-based materials for technical applications. Full article

The generation and stability of foam are critical attributes influencing the perceived efficacy and sensory experience of cleansing products like face cleansers and hair shampoos. This study rigorously investigated the influence of water hardness on the foam characteristics of a face cleanser and hair shampoo through integrated macroscopic, microscopic, and rheological analyses. Hard water consistently induced severe foam destabilization, evidenced by significantly increased foam decay and shortened drainage half-lives. Microstructural analysis revealed pronounced bubble coalescence, manifested as reduced bubble counts and elevated mean bubble areas. Rheologically, hard water compromised foam viscoelasticity, leading to diminished complex moduli (G*), earlier G″/G′ crossovers, and heightened phase angles (δ), signifying a rapid transition to a predominantly viscous, unstable state. Conversely, soft water consistently yielded highly elastic foams with robust G* values, maintained G′ dominance, and low δ, indicative of superior structural integrity and temporal stability. Notably, controlled rate viscosity profiles remained unaffected by water hardness. These findings collectively demonstrate that divalent cations fundamentally undermine foam lamellar film stability, inducing profound structural and mechanical degradation. Concurrently, tribological measurements revealed that the face cleanser consistently exhibited higher coefficients of friction in hard water across varying sliding speeds, whereas the hair shampoo displayed a more complex, speed-dependent frictional profile that was comparatively less sensitive to water hardness. This underscores the critical necessity for formulation chemists to mitigate water hardness effects to ensure consistent product performance and sensory attributes. Full article

Nanomaterial-based systems (NBS) have emerged as transformative elements in advanced surface engineering, offering superior corrosion resistance, mechanical strength, and tribological resilience governed by unique phenomena inherent to the nanoscale. However, bridging the knowledge gap between these enhanced physicochemical properties and the metrological tools required to quantify them remains a critical challenge. This review provides a comprehensive examination of the fundamental mechanisms, state-of-the-art experimental techniques, and computational strategies employed to probe NBS behavior. The article first elucidates the core mechanisms driving performance, including passive barrier formation, stimuli-responsive active corrosion inhibition, grain boundary strengthening, and the formation of protective tribo-films by 2D nanomaterial-based systems. Subsequently, the article evaluates the transition from conventional macroscopic testing to high-resolution in situ characterization, highlighting the capabilities of High-Speed Atomic Force Microscopy (HS-AFM), Liquid Cell Transmission Electron Microscopy (LC-TEM), and nanoindentation in visualizing dynamic defect evolution and measuring localized mechanical responses. Furthermore, the indispensable role of computational materials science—specifically Molecular Dynamics (MD) and Machine Learning (ML)—in predictive modeling and elucidating atomic-scale interactions is discussed. Finally, persistent challenges regarding substrate interference, sample heterogeneity, and instrumentation limits are addressed, concluding with a perspective on future research directions focused on standardization, operando testing, and the development of AI-driven “Digital Twins” for accelerated testing and material optimization. Full article

We are witnessing a global commitment to sustainable mobility that requires advanced materials and manufacturing techniques, such as fused filament fabrication (FFF), to create lightweight, durable, and recyclable machine components. Acknowledging that friction and wear significantly contribute to energy loss globally, developing high-performance polymeric materials with customizable properties is essential for greener mechanical systems. FFF inherently drives resource efficiency and offers the geometric freedom necessary to engineer complex internal structures, such as the gyroid pattern, enabling substantial mass reduction. This study evaluates the tribological performance of FFF-printed thermoplastic polyurethane (TPU 82A) specimens fabricated with three distinct gyroid infill densities (10%, 50%, and 100%). Ball-on-disc testing was conducted under dry sliding conditions against a 100Cr6 spherical ball, with a constant normal load of 5 N, resulting in an initial maximum theoretical Hertz contact pressure of 231 MPa, over a total sliding distance of 300 m. Shore A hardness and surface roughness (R_a) were also measured to correlate mechanical and structural characteristics with frictional response. Results reveal a non-monotonic relationship between infill density and friction, with a particular absence of quantifiable mass loss across all samples. The intermediate 50% infill (75.9 ± 1.80 Shore A) exhibited the peak mean friction coefficient of $\overline{\mu }=1.002$ (${\mu }_{\max }=1.057$), which can be attributed to its balanced structural stiffness that promotes localized surface indentation and an increased real contact area during sliding. By contrast, the rigid 100% infill (86.3 ± 1.92 Shore A) yielded the lowest mean friction ($\overline{\mu }$ = 0.465), while the highly compliant 10% infill (44.3 ± 1.94 Shore A) demonstrated viscoelastic energy damping, stabilizing at $\overline{\mu }$ = 0.504. This work highlights the novelty of using FFF gyroid architectures to precisely tune TPU 82A’s tribological behavior, offering design pathways for sustainable mobility. The ability to tailor components for low-friction operations (e.g., μ ≈ 0.465 for bushings) or high-grip requirements (e.g., μ ≈ 1.002 for anti-slip systems) provides eco-efficient solutions for automotive, railway, and micromobility applications, while the exceptional wear resistance supports extended service life and material circularity. Full article

This work presents a comparative study of TiSiC and TiSiCN composite coatings deposited on stainless steel by reactive plasma spraying using mechanically activated powders. Microstructure, phase composition, and hardness were assessed by SEM/EDS, XRD, and Vickers indentation, while corrosion, erosion, and high-temperature tribological behavior were systematically evaluated. The TiCN + SiC + Si system forms a stable TiC_xN_1−x solid solution with amorphous Si₃N₄ grain-boundary phases, leading to densification and enhanced chemical stability. Compared with TiSiC, TiSiCN coatings exhibit higher hardness (2599 N/mm², ≈324 HV), lower erosion loss (<1 mg), and stable friction coefficients (0.45–0.50 at 600 °C) due to protective oxide/nitride tribofilms. Electrochemical tests in 3.5 wt.% NaCl show a >6-fold reduction in corrosion rate (from 0.0506 to 0.008 mm·year⁻¹) relative to bare steel. Overall, TiSiCN coatings deposited at 500–600 A provide an optimal balance of hardness, wear, and corrosion resistance, indicating strong potential for gas-turbine and power-generation components operating in aggressive environments. Full article

This study examines the rheological and tribological behavior of bio-based nano-lubricants enhanced with cerium oxide (CeO₂) and multi-walled carbon nanotubes (MWCNTs), alongside the application of artificial intelligence (AI) models for performance prediction. Rheological results confirmed non-Newtonian, shear-thinning behavior across all formulations. CeO₂-based lubricants exhibited significantly higher viscosities at 40 °C (up to ~3700 mPa·s at low shear), which decreased sharply with shear, indicating strong particle interactions. In contrast, MWCNT-based lubricants maintained moderate viscosities (90–365 mPa·s at 40 °C) with improved flowability due to nanotube alignment. At 100 °C, both systems showed viscosity reduction, stabilizing between 8 and 18 mPa·s, which favors pumpability in high-temperature applications. Tribological testing revealed distinct performance characteristics. CeO₂ lubricants showed slightly higher coefficients of friction (0.144–0.169) but excellent wear resistance, achieving the lowest wear rate of 1.66 × 10⁻⁶ mm³/N-m. MWCNT-based lubricants offered stable and lower CoF values (0.116–0.148) while also providing very low wear rates, with MCO6 achieving 1.62 × 10⁻⁶ mm³/N-m. However, ternary blends (C20T80 and M20T80) displayed moderate CoF but significantly higher wear rates (up to 2.92 × 10⁻⁵ mm³/N-m), suggesting that blending improves dispersion but weakens tribo-film stability. To complement the experimental findings, support vector regression (SVR), artificial neural networks (ANN), and AdaBoost algorithms were employed to predict key performance parameters based on compositional and thermal input data. The models demonstrated high prediction accuracy, validating the feasibility of AI-driven formulation screening. These results highlight the complementary potential of CeO₂ and MWCNT additives for high-performance bio-lubricant development and emphasize the role of machine learning in accelerating material optimization for sustainable lubrication systems. Full article

FeCoCrNiNb_xN (x = 0, 0.25, 0.5, 0.75, 1 molar) high-entropy nitride (HEN) films were fabricated on 304 stainless steel and Si wafers using magnetron sputtering to investigate the influence of Nb content on the microstructure, mechanical properties, and tribological performance. X-ray diffraction (XRD) analysis reveals a face-centered cubic (FCC) structure with a preferred orientation in the (200) plane, which transfers to the (111) plane as the Nb content increases. The lattice distortion induced by Nb incorporation enhanced crystallinity, with the Nb_0.5N film exhibiting the highest diffraction peak intensity and interplanar distance. Cross-sectional SEM images displayed columnar crystal structures, while the surface morphology evolved from “cauliflower-like” to smoother clusters with increasing Nb content, reducing average roughness from 7.54 nm (Nb₀) to 4.89 nm (Nb₁). The hardness and elastic modulus initially decrease, then peak at 25.56 GPa and 265.36 GPa, respectively, for the Nb₁ film, attributed to solid solution strengthening and high-entropy effects. Tribological tests demonstrated that Nb₁ achieved the lowest coefficient of friction (0.46), wear volume (1.23 × 10⁻³ mm³), and wear rate (5.11 × 10⁻⁸ mm³·N⁻¹·m⁻¹), owing to NbN phase formation, refined grains, and reduced surface roughness. The wear mechanisms are abrasive and oxidative wear. Full article

To address the demands of modern high-speed and high-quality continuous casting production, depositing high-performance coatings on the surface of mold copper plates is critically important for extending the service life of continuous casting molds. To this end, a Ni-Co-Cr/SiC nanocomposite coating was developed, and cryogenic treatment was applied to further improve its hardness and wear resistance. This work systematically investigates the microstructural evolution and performance enhancement of the Ni-Co-Cr/SiC nanocomposite coating under different cryogenic treatment parameters, with special emphasis on the effects of treatment temperature on the coating’s microstructure, hardness, wear resistance, and adhesion to the substrate. The results demonstrate that decreasing the cryogenic treatment temperature and extending the holding time effectively refine the grains of the coating while simultaneously promoting the accumulation of microstrain and dislocation density. These changes lead to significant improvements in hardness, wear resistance, and interfacial bonding performance. Specifically, after direct immersion at −196 °C for 16 h, the coating reached a hardness value of 946.5 HV, and the wear rate was reduced to 0.032 mm³·(N·m)⁻¹, representing only 54.6% of that of the untreated coating. The dominant wear mechanism transitioned to a mixed mode of abrasive wear and oxidative wear. Moreover, the cryogenic treatment enhanced the stability of the coating-substrate adhesion. Full article

Fe-Cr-Al coatings were obtained by air plasma spraying (APS) from 85Fe-12Cr-3Al and 68Fe-26Cr-6Al powders at two hydrogen flow rates (8 and 13 L/min), which resulted in four deposition regimes (A1, A2, B1, B2). Stainless steel 20Kh13 (equivalent to AISI 420) was used as the substrate material. The microstructure of the coatings has a typical lamellar layering with molten and semi-molten particles. When the hydrogen flow rate is increased to 13 L/min, a denser and more homogeneous structure with reduced porosity is observed. X-ray phase analysis revealed the presence of metal and oxide phases (Fe,Cr), Fe₃O₄, FeO, Fe²⁺Cr₂O₄, which indicates partial oxidation of particles during the spraying process and stabilization of the structure. Electrochemical tests in 3.5% NaCl solution showed that the 85Fe-12Cr-3Al coatings are characterized by a corrosion potential of E_o ≈ −0.60…−0.67 V, a corrosion current density of i_o = (2.6–4.7) × 10⁻⁵ A/cm², and a corrosion rate of 0.30–0.55 mm/year, whereas the 68Fe-26Cr-6Al coatings exhibit lower values of i_o = (1.4–2.9) × 10⁻⁵ A/cm² and a corrosion rate of 0.17–0.34 mm/year, indicating the formation of a denser protective oxide film (Cr₂O₃ + Al₂O₃) and enhanced surface passivation. Tribological tests showed that 85Fe-12Cr-3Al coatings demonstrate more stable friction compared to 68Fe-26Cr-6Al, while for regime B2, after 180 m, an increase in the friction coefficient is observed, caused by brittleness and the local destruction of the oxide film. A comprehensive analysis of the results showed that increasing the hydrogen consumption to 13 L/min improves the density and corrosion–tribological characteristics of the coatings. Full article

Background: Cu-based friction materials (CBFMs) exhibit significant application in transportation and mechanical engineering due to their excellent wear resistance, thermal conductivity, and stable tribological performance. Methods: In this study, CBFMs holding a 3D mesh reinforcement structure was prepared under different sintering temperatures and sintering times. The phase, mechanical, and tribological properties were tested, and the wear mechanisms were analyzed. Results: The results showed that with an increase in sintering temperature, compressive strength showed a trend of increasing first and then decreasing, COF showed a decreasing trend first and then an increasing trend, and wear rate showed a decreasing trend that can be attributed to the different strength of the matrix and 3D mesh reinforcement structure at different sintering temperatures. With an increase in sintering time, COF continuously increased and wear rate sustained a decrease. Conclusions: Compared with previous studies, this study revealed the influence mechanism of sintering temperature and sintering time on the comprehensive properties of CBFMs holding a 3D mesh reinforcement structure for the first time. The results can provide data support for the performance improvement of CBFMs holding a 3D mesh reinforcement structure, and lay a theoretical foundation for the further study of powder metallurgy materials. Full article

The influence of electron beam melting (EBM) scan speed on the corrosion, nano-biotribological, and cellular adhesion properties of Ti-6Al-4V-ELI (extra low interstitials) was systematically investigated. Specimens were fabricated using five different scanning speeds, and tribological performance was assessed via reciprocating dry wear tests, while corrosion behaviour was evaluated through monitoring the open circuit potential and anodic potentiodynamic polarization tests in Ringer’s solution. Human fibroblasts from the FN1 cell line were used to assess cell adhesion. Specimens produced using scanning speeds of 4530 mm·s⁻¹ and 4983 mm·s⁻¹ exhibited increased passive current densities, indicating reduced corrosion protection, although all surfaces maintained the passive film characteristic. Tribological behaviour was strongly dependent on scan speed, with wear rate and penetration depth increasing at higher speeds; notably, an intermediate scan speed produced a surface with minimal wear and penetration depth despite a wide wear track, suggesting enhanced resistance to tribological degradation. Fibroblast cultures demonstrated robust adhesion and spindle-shaped morphology across all samples, with the disk produced using a scanning speed of 4983 mm·s⁻¹ showing the highest surface coverage, highlighting the role of EBM process parameters in modulating surface properties relevant to cell–biomaterial interactions. These findings underscore the critical influence of scan speed on the multifunctional performance of Ti-6Al-4V-ELI for biomedical applications. Full article

In order to improve the high-temperature wear resistance of mold copper plates, this study used laser cladding technology to prepare a high-wear-resistant composite coating with Inconel 718 and WC(Tungsten carbide) particles. The phase composition, microstructure, microhardness, and tribological properties at 400 °C were systematically analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Vickers microhardness tester, and high temperature friction and wear tester. The results indicate that the Inconel 718/WC coating is free of pores and cracks and exhibits a metallurgical bond with the substrate. Its phases mainly consist of a γ-Ni solid solution and various hard carbide reinforcing phases, such as MC, M₃W₃C, and W₂C. The average microhardness of the coating reaches 851.7 HV_0.5, which is 11.5 times than that of the substrate (74 HV_0.5). At 400 °C, the wear rate of the coating is 3.48 × 10⁻⁴·mm³·N⁻¹·m⁻¹, only 35.7% of the substrate’s wear rate. The dominant wear mechanism is abrasive wear, accompanied by oxidative wear. The outstanding performance of the coating is attributed to the combined effects of grain refinement strengthening, solid solution strengthening, and second-phase strengthening induced by the various hard carbides. Full article

To extend the service life of sensors in seawater, this work prepared an integrated diffusion-plated Al₂O₃ film using high-power impulse magnetron sputtering (HiPIMS). The tribological properties of the Al₂O₃ film in a marine environment were tested using a tribometer. The morphology and evolution of the Al₂O₃ film before and after the friction tests were investigated by characterization techniques such as field emission scanning electron microscopy (FESEM). The results demonstrate that the Al₂O₃ film exhibits excellent tribological performance in the marine environment, significantly enhancing the wear resistance of the substrate material. Furthermore, with the protection of the Al₂O₃ film, the designed pressure sensor achieved high-sensitivity detection of minute operational forces underwater. When applied to a robotic gripper for manipulation tasks, the coated underwater sensor enabled accurate perception of subtle motion states of the grasped objects. Full article

One of the limitations of additive manufacturing technology is the high surface roughness of finished products caused by the layered structure of the deposition and the effect of adhesion of unfused powder particles. This worsens the fatigue characteristics, wear resistance, and functional properties of the parts, which are especially important for critical applications in medicine, aviation, and mechanical engineering. The paper presents the results of a study on the possibility of using plasma electrolytic polishing for post-processing of products made of additively manufactured Ti6Al4V alloy to form a homogeneous surface with reduced roughness. The morphology, roughness, and tribotechnical characteristics of the surface after processing in a fluoride electrolyte were studied with varying voltage and polishing time. A 90% reduction in surface roughness is achieved by polishing at 300 V for 20 min. The results of tribological tests revealed that after the polishing of the oxidative wear mechanism is maintained, the temperature in the tribological contact zone decreases, and the load-bearing capacity of the surface increases (the Kragelsky–Kombalov criterion decreases). The greatest decrease in the friction coefficient by 2.1 times was observed with minimal surface roughness, when the largest average radius of rounding of the microprotrusions of the friction track microtopology is formed with a low value of the Kragelsky–Kombalov criterion. Full article

This study focuses on surface modification of aluminum alloys (Al–Si) with high silicon content using plasma electrolytic oxidation (PEO). The influence of Al₂O₃ and SiO₂ particles, introduced both separately and in combination, into a sodium aluminate-based electrolyte during high-frequency treatment (2000 Hz). Examination of surface and cross-sections using a scanning electron microscope SEM showed an increase in the compactness of the coating when Al₂O₃ particles were introduced. The addition of SiO₂ particles tended to promote a smoother surface and a slight reduction in the porosity and defect density. However, when these particles are added together, especially at high concentrations, an increase in structural defects and crack formation is observed. X-ray diffraction analysis revealed that the γ-Al₂O₃ phase was present in all coatings. In the samples with Al₂O₃ addition, the α-Al₂O₃ diffraction signal became stronger compared with the other coatings. Tribological tests revealed that the addition of Al₂O₃ particles significantly improved wear resistance, while the introduction of SiO₂ particles contributed to the stabilization of the friction coefficient. Thus, Al₂O₃ particles were the most effective in enhancing the mechanical properties of the coating. Full article