Search Results (212)

This study investigates the enhancement of AA6082/Al₂O₃ aluminum metal matrix nanocomposites (AMMNCs) through powder metallurgy combined with systematic process optimization. Ultrasound-assisted dispersion and Taguchi design L9 orthogonal array were employed to improve nanoparticle distribution and optimize fabrication parameters. The effect of Al₂O₃ content and ultrasonication time (UT) on hardness and compressive strength was analyzed using S/N ratio and ANOVA. Characterization was performed using X-ray Diffraction (XRD) and scanning electron microscopy (SEM). The result shows that Al₂O₃ content had the most significant influence on both hardness (82.25%) and compressive strength (81.08%), followed by UT. The optimal condition produced a maximum hardness of 31.9 HV and compressive strength of 205.53 MPa. Regression models demonstrated strong predictive accuracy (R² > 85%). Overall, the study highlights the effectiveness of parameter optimization in improving nanocomposite performance and provides valuable guidance for advanced material design. Full article

Surface discharge-induced degradation poses a significant threat to the operational reliability of high-voltage insulation systems. This research investigates the dielectric endurance of polyester-based nanocomposites reinforced with seven distinct nano-additives: iron oxide (Fe₃O₄), copper oxide (CuO), titanium oxide (TiO₂), aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), zinc borate (ZnB) and graphene oxide (GO). Specimens were fabricated at 0.5% and 0.75% weight concentrations and subjected to constant AC electrical stress of 4.5 kV at 50 Hz until failure using the first-plane tracking method. To accurately monitor the aging process, a sophisticated signal processing framework involving Hankel-matrix-enhanced Robust Principal Component Analysis (RPCA) was developed to extract high-frequency discharge features from captured leakage current signals. The degradation characteristics were quantified using various statistical metrics, including Kurtosis, RMS and Burst Discharge Index (BDI). Experimental findings demonstrate that the incorporation of nanoparticles significantly extends the time-to-failure compared to neat polyester, although the effectiveness is highly dependent on both additive type and concentration. At 0.5 wt.%, ZnB exhibited the superior performance in delaying carbonized track formation. However, at 0.75 wt.%, Al₂O₃ emerged as the most effective additive, achieving a maximum endurance time of 31.61 min. In contrast, certain additives like TiO₂ showed a performance decline at higher loadings, likely due to nanoparticle agglomeration. The Hankel-RPCA methodology successfully isolated discharge-specific signatures from background noise, establishing a strong correlation between signal features and material failure stages. This study confirms that the synergy between advanced nanomaterial modification and robust signal processing provides an effective diagnostic tool for monitoring insulation health, offering a vital pathway for the designing of high-performance dielectrics for real-world power system applications. Full article

Copper functions as an exceptionally efficient conductor, garnering considerable interest in electrical and thermal applications; however, its relatively malleable nature and insufficient durability may hinder its structural effectiveness. This study focused on the development of copper-based nanocomposites by reinforcing a copper matrix with co-precipitated CuO/Al₂O₃ nanoparticles (varying from 0 to 10 wt% in increments of 2%). A thorough examination was conducted regarding the microstructural characteristics, mechanical properties, and the electrical and thermal conductivities of the composites. X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) analysis validated the successful synthesis of nano-sized CuO and Al₂O₃ phases, with an estimated crystallite size of 33.2 ± 2.4 nm. Scanning electron microscopy revealed a relatively uniform distribution of nano-oxides within the copper matrix, albeit with signs of particle agglomeration at higher loading levels. The durability of the copper exhibited a significant enhancement attributed to the nano-oxide reinforcement, achieving an 180% increase relative to pure copper with a 10% reinforcement addition. Consequently, the tensile strength increased by approximately 68% (from around 154 MPa to nearly 260 MPa), while maintaining an exceptional level of ductility. The electrical conductivity of copper remained largely unchanged with the addition of nanoparticles; rather, a slight improvement in conductivity and a ~30% rise in thermal conductivity were observed at the maximum reinforcement level. This research work presents a copper-based nanocomposite that offers remarkable potential for applications requiring enhanced strength, wear resistance, and exceptional electrical and thermal conductivity. Full article

Hybrid nanocomposites based on Aluminum 6061 (Al 6061) reinforced with carbon nanotubes (CNTs) and aluminum oxide (Al₂O₃) emerge as promising materials due to their ability to achieve simultaneous improvements in strength, thermal stability, and tribological performance. This study examines the structure–property relationships of CNT–Al₂O₃ nano-reinforced hybrid Al 6061, with particular emphasis on microstructural evolution and mechanical properties. The nanocomposites are fabricated via a powder metallurgy route, which enables optimized dispersion and homogeneous distribution of CNTs and Al₂O₃ within the aluminum matrix. Microstructural characteristics, interfacial bonding, and grain refinement are systematically analyzed using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Mechanical characterization demonstrates a marked enhancement in mechanical properties compared to Al 6061. The observed property improvements are attributed to synergistic strengthening mechanisms, including effective load transfer from the matrix to Al₂O₃ particles, CNT-induced grain refinement, and increased resistance to dislocation motion. These results establish a direct correlation between microstructural features and mechanical performance, highlighting the potential of CNT–Al₂O₃ reinforced Al 6061 hybrid nanocomposites for lightweight, high-strength applications in aerospace, automotive, and structural engineering industries. Full article

Porous ceramic oxides have gained significant interest as components in a wide variety of energy storage devices. Their use, however, is limited by long and high-temperature processing methods. We recently demonstrated Porogen-integrated Rapid Oxidation (PiRO) as a new method to manufacture porous aluminum oxide in significantly shorter times and with substantial manufacturing cost savings, but challenges remain with the resultant porous matrices. First, carbonaceous residue remains in the films after the combustion event, which is necessary to minimize for electronic applications. Second, the porous structure is not stable at elevated temperatures (>250 °C), which are often required for nanocomposite applications of the matrices where filling with a second phase is achieved through high-temperature annealing. Here, we address these challenges by using post-processing treatments, including UV/Ozone, high-temperature nitrogen oven anneals, and oxygen plasma. First, we characterize the treatments’ efficacy in carbon removal using FTIR and measure bulk carbon removal with XPS. Second, we characterize the matrices’ thickness collapse and porosity changes after treatments with ellipsometry. Finally, we use nanoindentation to understand changes in stiffness resulting from the various treatments. By understanding the treatments’ roles in removing carbon from the films and stabilizing the matrix structure, we are able to select optimal post-processing treatments for designing a stable platform for further applications of the mesoporous oxide. Full article

In this study, B₄C nanoparticles were incorporated into AA2024, one of the aluminum alloys with superior mechanical and wear properties, with the aim of further enhancing its mechanical, tribological, and corrosion performance. The nanocomposites were produced using mechanical milling followed by powder metallurgy techniques. The effects of nano-sized B₄C additions on powder characteristics, microstructure, and physical, mechanical, tribological, and corrosion properties were systematically investigated through microhardness, density, SEM, XRD, bulk hardness, wear, and corrosion tests. B₄C was added at weight fractions of 0–2 wt.%, and all samples were mechanically milled for 8 h. The results revealed a gradual reduction in powder particle size and a corresponding increase in particle microhardness with increasing B₄C content. The sample reinforced with 2 wt.% nano-B₄C exhibited an approximately 80% increase in hardness and around a 55% improvement in tensile strength compared to the unreinforced alloy. Wear resistance was significantly enhanced, showing up to an 8-fold improvement under a 5 N load and a 6-fold improvement under a 25 N load. Furthermore, corrosion resistance nearly doubled with the addition of B₄C nanoparticles. Full article

Corrosion in harsh environments causes global economic losses exceeding 3 trillion US dollars annually. Traditional silicone epoxy (SE) coatings are prone to failure due to insufficient physical barrier properties and lack of active protection. In this study, cerium dioxide (CeO₂) was in situ grown on the surface of hexagonal boron nitride (h-BN) mediated by polydopamine (PDA) to prepare BN-PDA-CeO₂ ternary nanocomposites, which were then incorporated into SE coatings to construct a multi-scale synergistic corrosion protection system. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) confirmed the successful preparation of the composites, where PDA inhibited the agglomeration of h-BN and CeO₂ was uniformly loaded. Electrochemical tests showed that the corrosion inhibition efficiency of the extract of this composite for 2024 aluminum alloy reached 99.96%. After immersing the composite coating in 3.5 wt% NaCl solution for 120 days, the coating resistance (Rc) and charge transfer resistance (Rct) reached 8.5 × 10⁹ Ω·cm² and 1.2 × 10¹⁰ Ω·cm², respectively, which were much higher than those of pure SE coatings and coatings filled with single/binary fillers. Density functional theory (DFT) calculations revealed the synergistic mechanisms: PDA enhanced interfacial dispersion (adsorption energy of −0.58 eV), CeO₂ captured Cl⁻ (adsorption energy of −4.22 eV), and Ce³⁺ formed a passive film. This study provides key technical and theoretical support for the design of long-term corrosion protection coatings in harsh environments such as marine and petrochemical industries. Full article

This investigation has yielded a remarkably efficient metallic catalyst. Copper (Cu), cobalt (Co), and nickel (Ni) nanoparticles were concurrently deposited onto micron-sized aluminum (µAl) through a displacement reaction, resulting in the formation of [nCu+nCo+nNi]/µAl composites. The interfacial layer of the nanocomposite facilitates the creation of efficient oxygen transport pathways, significantly augmenting thermal release. In the context of the ADN/AP oxidizer, the [nCu+nCo+nNi]/µAl configuration demonstrates a substantial synergistic catalytic effect, reducing its thermal decomposition temperature by an impressive 104.1 °C. Combustion experiments have corroborated that this composite markedly enhances flame intensity, combustion temperature, and the burning rate of the ADN/AP system. The underlying thermal-oxidative mechanism was elucidated through comprehensive thermal analysis of the composite both prior to and following a heat treatment at 1100 °C. Moreover, through an integration of thermal analysis and combustion experiments, the catalytic mechanism of [nCu+nCo+nNi]/µAl on the thermolysis of ADN/AP was elucidated, and a plausible reaction pathway under thermal stimulation was proposed (e.g., ${\mathrm{NH}}_4{\mathrm{ClO}}_4+{{\mathrm{NH}}_4\mathrm{N}({\mathrm{NO}}_2)}_2\stackrel{\mathrm{Cu},\mathrm{Co},\mathrm{Ni}}{\to }{\mathrm{N}}_2+{\mathrm{H}}_2\mathrm{O}+\mathrm{HCl}+{\mathrm{O}}_2+\left[\mathrm{O}\right]$). The developed nanocomposite significantly enhances the performance of oxidizers, presenting considerable potential for a wide array of applications in solid propellants. Full article

This study investigated the effect of nanofiller on the structural properties of thermally aged polyvinyl chloride (PVC)/Aluminum oxide (Al₂O₃) nanocomposites prepared with different amounts of nanoparticles (2.5, 5.0, and 7.5 wt%) using various techniques. Experimental studies were designed to monitor structural changes in PVC/Al₂O₃ nanocomposites by means of dielectric characterization, charging and discharging currents measurements, SEM and FTIR analyses, and visual observations as a function of nanofiller amount and aging time. The results obtained demonstrated that the dielectric permittivity of PVC was increased for unaged samples with the addition of 2.5% and 7.5% Al₂O₃ nanoparticles. An increase in dielectric losses is also observed at the same level of filler content, attributable to interfacial polarization driven by improved charge transport and dipole relaxation. A decrease in charging and discharging currents with higher Al₂O₃ content is attributed to an increase in matrix rigidity, which restricts charge carrier mobility. The charging and discharging currents progressively increased during thermal aging, as polar aging products were formed during this process, which could improve charge mobility and conductivity. FTIR and SEM analyses indicated that with thermal aging, polar groups formation was more likely due to structural decomposition of the matrix and mild dehydrochlorination. The changes in color were indicative of surface degradation. These results provide new insight into the electrical and aging behaviors in PVC/Al₂O₃ nanocomposites. Full article

In this study, the tribological compatibility of ZrO₂-nanofiber-strengthened Al-matrix composites with graphene nanoplatelets (GNPs)-derived surface film acting as a solid lubricant was investigated. The substrate materials prepared by Spark Plasma Sintering (SPS) included the pure aluminum monolith (reference material) and two Al–ZrO₂ nanocomposites with either 1 or 3 wt.% of ZrO₂ nanofibers. The GNPs-derived solid lubricant films were dry mechanically burnished into the metallographically polished surfaces. The durability of these burnished films was evaluated by performing tribological friction experiments using a ball-on-disk method. Thus, a friction load capacity of GNP-derived tribofilms on the substrate materials and its effect on the coefficient of friction (COF) were evaluated. The results showed that the films burnished on the surfaces of Al–ZrO₂ nanofiber composites were more resistant to much higher loads than films burnished on monolithic aluminum. The obtained findings indicated that ZrO₂ nanofiber protrusions likely stabilize a GNP-derived carbon tribolayer on the polished composite surfaces. As a result, the reinforcement of aluminum with ceramic nanofibers led also to a significant reduction in COF. The highest improvement of tribological performance was observed for the Al–ZrO₂ nanofiber composite with 1 wt.% ZrO₂ nanofibers. The increase of ZrO₂ nanofibers up to 3 wt.% was no more efficient due to nanofiber clustering leading to lower stability of the carbon friction film. Our objective was to isolate the role of the aluminum substrate, specifically, ZrO₂ nanofiber protrusions in the formation and retention of a GNP-derived carbon tribofilm under room-temperature, ambient-air dry sliding. Full article

Polyaspartic ester polyurea (PEP) elastomers are highly promising for self-healable protective coatings in industrial applications, yet their broader adoption is limited by insufficient mechanical and corrosion resistance. Herein, we develop a multifunctional PEP nanocomposite by incorporating Jeffamine D2000-functionalized graphene nanoplatelets (F-GNPs), prepared through a one-step mechanochemical process. This strategy promotes strong interfacial bonding and uniform dispersion, yielding synergistic property enhancements. At an optimal loading of 0.3 wt%, the PEP/F-GNP nanocomposite exhibited a substantial performance enhancement, with its tensile and tear strengths augmented by 263.0% and 64.2%, respectively. Moreover, the resulting coating delivered an 84.0% boost in impact resistance on aluminum alloy, along with enhanced substrate adhesion. Electrochemical and salt spray tests further confirmed its exceptional anti-corrosion performance. While the reinforcement strategy presented a classic trade-off with self-healing, it is critical to note that the nanocomposite preserved a high healing efficiency of 83.3% after impact damage. Overall, this scalable interfacial engineering strategy simultaneously enhances the material’s mechanical robustness and protective performance, while striking a favorable balance with its intrinsic self-healing capability, paving the way for next-generation coatings. Full article

Background: Skin injuries, such as chronic wounds and inflammatory skin diseases, often face limitations in treatment efficacy due to the low efficiency of transdermal drug delivery and insufficient local concentrations. Curcumin (CUR), a natural compound with anti-inflammatory and antioxidant properties, has demonstrated potential in the repair of skin damage; however, its clinical application is hindered by its physicochemical characteristics. This study constructs a novel nanocomposite drug delivery system: CUR-loaded micellar nanocomposite gel (CUR-M-DMNs-Gel). A composite system is used to achieve the efficient solubilization and enhanced transdermal permeation of CUR, thereby providing a novel formulation approach for the treatment of skin diseases. Methods: CUR-loaded micellar (CUR-M) utilizes CUR as the core active ingredient, which possesses multiple pharmacological effects including anti-inflammatory and antioxidant properties. TPGS serves as a micellar carrier that not only enhances the solubility and stability of CUR through its amphiphilic structure but also facilitates drug absorption and transport within the body. In dissolvable microneedles (DMNs), PVP K30 forms a stable three-dimensional network structure through entanglement of polymer chains, ensuring sufficient mechanical strength for effective penetration of the skin barrier. Meanwhile, PVP K90, with its higher molecular weight, enhances the backing’s support and toughness to prevent needle breakage during application. The incorporation of hyaluronic acid (HA) improves both the moisture retention and adhesion properties at the needle tips, ensuring gradual dissolution and release of loaded CUR-M within the skin. In CUR-loaded micellar gel (CUR-M-Gel), PVP K30 increases both adhesive and cohesive forces in the gel through chain entanglement and hydrogen-bonding interactions. Tartaric acid precisely regulates pH levels to adjust crosslinking density; glycerol provides a long-lasting moisturizing environment for the gel; aluminum chloride enhances mechanical stability and controlled drug-release capabilities; NP-700 optimizes dispersion characteristics and compatibility within the system. Results: In vitro experiments demonstrated that the CUR-M-DMNs-Gel composite system exhibited enhanced transdermal penetration, with a cumulative transdermal efficiency significantly surpassing that of single-component formulations. In the mouse skin defect model, CUR-M-DMNs-Gel facilitated collagen deposition and effectively inhibited the expression of inflammatory cytokines (TNF-α, IL-6, and IL-1β). In the mouse skin photoaging model, CUR-M-DMNs-Gel markedly reduced dermal thickness, alleviated damage to elastic fibers, and suppressed inflammatory responses. Conclusions: The CUR-M-DMNs-Gel system can enhance wound healing through subcutaneous localization, achieving long-term sustained efficacy. This innovative approach offers new insights into the treatment of skin injuries. Full article

Cold gas dynamic spraying (CGDS) enables the production of protective coatings without melting or oxidation. In this study, Al–Zn–TiO₂ composite powders were prepared by wet agglomeration with binders and by dry mechanical mixing, and deposited onto mild steel substrates. COMSOL simulations of gas dynamics and particle acceleration identified optimal parameters (0.6 MPa, 600 °C, 15 mm, 90°), which were then validated experimentally. Coatings formed under these conditions exhibited dense microstructures, minimal porosity (~0.5%), and continuous, defect-free interfaces with the substrate. SEM and XRD confirmed solid-state bonding without new phase formation. Corrosion tests in 3.5% NaCl revealed a tenfold reduction in corrosion current density compared to bare steel, resulting from synergistic sacrificial (Zn), barrier (Al), and reinforcing/passivating (TiO₂) effects. Tribological tests demonstrated reduced friction (CoF ≈ 0.4–0.5) and wear volume. Compared with reported Al- or Zn-based cold- and thermal-sprayed coatings, the optimized Al–Zn–TiO₂ system shows superior performance, highlighting its potential for industrial anti-corrosion and wear-resistant applications. Full article

Al-based nanocomposite energetic materials have broad application prospects in explosives and propellants, owing to their excellent energy release efficiency. However, their insufficient reliability, poor stability, and difficulty of formation limit their practical application. This study employed self-assembly using a hydrophilic polymer polyvinylpyrrolidone (PVP) together with nano-aluminum powder (Al), copper oxide (CuO), and ammonium perchlorate (AP) to obtain high-strength and high-activity composite micrometer-sized microspheres. The influence of PVP concentration on the mechanical behavior of Al/AP composite microspheres was systematically investigated, and Al was replaced with ultrasonically dispersed Al/CuO to explore the mechanism of action of PVP in the system and the catalytic behavior of CuO. PVP significantly enhanced the interfacial bonding strength. The Al/AP/5%PVP microspheres achieved a strength of 8.4 MPa under 40% compressive strain, representing a 365% increase relative to Al/AP. The Al/CuO/AP/5%PVP microspheres achieved a strength of 10.2 MPa, representing a 309% increase relative to Al/CuO. The mechanical properties of the composite microspheres were improved by more than threefold, and their thermal reactivities were also higher. This study provides a new method for the controlled preparation of high-strength, high-activity, micrometer-sized energetic microspheres. These materials are expected to be applied in composite solid propellants to enhance their combustion efficiency. Full article

Electrospun nanofiber membranes based on cellulose acetate (CA) have gained increasing attention for wastewater treatment due to their high surface area, tuneable structure, and ease of functionalization. In this study, the performance of CA membranes was enhanced by incorporating aluminum oxide (Al₂O₃) nanoparticles (NPs) at varying concentrations (0–2 wt.%). The structural, morphological, and thermal properties of the resulting CA/Al₂O₃ nanocomposite membranes were investigated through FTIR, XRD, SEM, water contact angle (WCA), pore size measurements, and DSC analyses. FTIR and XRD confirmed strong interactions and the uniform dispersion of the Al₂O₃ NPs within the CA matrix. The incorporation of Al₂O₃ improved membrane hydrophilicity, reducing the WCA from 107° to 35°, and increased the average pore size from 0.62 µm to 0.86 µm. These modifications led to enhanced filtration performance, with the membrane containing 2 wt.% Al₂O₃ achieving a 99% removal efficiency for Indigo Carmine (IC) dye, a maximum adsorption capacity of 45.59 mg/g, and a high permeate flux of 175.47 L·m⁻² h⁻¹ bar⁻¹. Additionally, phytotoxicity tests using Lactuca sativa seeds showed a significant increase in germination index from 20% (untreated) to 88% (treated), confirming the safety of the permeate for potential reuse in agricultural irrigation. These results highlight the effectiveness of Al₂O₃-modified CA electrospun membranes for sustainable wastewater treatment and water reuse. Full article