Optimal Properties Research Articles

Incorporation of cerium oxide nanoparticles into the micro-arc oxidation layer promotes bone formation and achieves structural integrity in magnesium orthopedic implants

Biodegradable metals offer significant advantages by reducing the need for additional surgeries following bone fixation. These materials, with their optimal mechanical and degradable properties, also mitigate stress-shielding effects while promoting biological processes essential for healing. This study investigated the in vitro and in vivo biocompatibility of ZK60 magnesium alloy coated with a micro-arc oxidative layer incorporated with cerium oxide nanoparticles in orthopedic implants. The results demonstrated that the magnesium substrate undergoes gradual degradation, effectively eliminating long-term inflammation during bone formation. The micro-arc oxidative coating forms a dense ceramic layer, acting as a protective barrier that reduces corrosion rates and enhances the biocompatibility of the magnesium substrate. The incorporation of cerium oxide nanoparticles improves the tribological properties of the coating, refining degradation patterns and improving osteogenic characteristics. Furthermore, cerium oxide nanoparticles enhance bone reconstruction by facilitating appropriate interconnections between newly formed bone and native bone tissue. Consequently, cerium oxide nanoparticles contribute to favorable biosafety outcomes and exceptional bone remodeling capabilities by supporting bone healing and sustaining a prolonged degradation process, ultimately achieving dynamic equilibrium in bone formation. Statement of significanceThis study comprehensively examined the incorporation of cerium oxide nanoparticles into biodegradable magnesium through a micro-arc oxidative process for use in orthopedic implants. This study conducted a comprehensive analysis involving material characterization, biodegradability testing, in vitro osteogenesis assays, and in vivo implantation, highlighting the potential benefits of the distinctive properties of cerium oxide nanoparticles. This research emphasizes the ability of cerium oxide nanoparticles to enhance the biodegradability of magnesium and facilitate remarkable bone regeneration, suggesting promising advantages for additive materials in orthopedic implants.

Tensile fracture behavior and friction and wear properties of TiB2 particle reinforced Al-Si matrix composites

In this study, TiB2/Al-Si composite material was fabricated by addition of Al-TiB2 master alloy, and the influence of varying micro-sized TiB2 particle content on the mechanical and tribological properties of the composite material was investigated. The results revealed that the introduction of TiB2 particles effectively refined the Al-Si matrix alloy microstructure, thereby enhancing the mechanical properties and wear resistance of the Al-Si matrix alloy. When the TiB2 particle content reached 0.8 wt%, the composite material exhibited optimal mechanical properties with a tensile strength of 318 MPa and elongation of 7.2 %, improving of 8.9 % and 69.1 %, respectively, compared to the matrix alloy. Moreover, wear rates of the composite material demonstrated significantly lower than the matrix alloy under different loading conditions in this paper. The improved mechanical properties of the composite material were attributed to grain refinement strengthening, second phase strengthening and the coefficient of thermal expansion strengthening. Under low loads, abrasive wear was the dominant wear mechanism; while under high loads, a combination of abrasive and adhesive wear occurred. The addition of TiB2 particles effectively enhanced the hardness of the matrix alloy, reduced the dynamic friction coefficient, suppressed adhesive wear, and improved the wear resistance of the composite material.

Janus-structured MXene-PA/MS with an ultrathin intermediate layer for high-salinity water desalination and wastewater purification

Solar-driven interfacial evaporation presents significant potential for seawater desalination and wastewater purification. However, prolonged operation in marine environments often results in salt accumulation, which adversely impacts the performance and lifetime of system. Despite the progress in material design, achieving efficient evaporation while mitigating salt crystallization remains challenging in high-salinity water. In this study, we synthesized a hierarchically structured C18H37-MXene/PA/MS evaporator employing a simple yet effective methodology specifically designed for applications in high-salinity water environments. The evaporator features a dual-region configuration, with an upper hydrophobic light-absorbing layer comprising modified MXene and polyamide (PA) membranes and a hydrophilic lower layer consists of hydrophilic melamine sponge (MS). This innovative design, incorporating an ultra-thin polyamide interlayer, significantly enhances interfacial stability, thereby mitigating the interfacial separation typically observed in conventional Janus materials during prolonged usage. Furthermore, the meticulous control over the thickness of the hydrophobic layer (5.54 μm) ensures optimal thermal insulation properties of the material. Consequently, the C18H37-MXene/PA/MS evaporator demonstrates an impressive evaporation rate of 1.49 kg m−2 h−1 under 1 sun illumination, with a high energy efficiency of 92.8 %. Furthermore, the Janus architecture ensures steady performance in high salinity conditions, sustaining a high evaporation rate of 1.46 kg m−2 h−1 even in a 20 wt% NaCl solution. Furthermore, under natural sunlight, the daily freshwater yield reaches 8.91 kg m−2. The exceptional evaporation efficiency and robust salt resistance highlight its strong potential for water desalination and wastewater treatment, contributing to the advancement of sustainable water resource management.

An RGD-Conjugated Prodrug Nanoparticle with Blood-Brain-Barrier Penetrability for Neuroprotection Against Cerebral Ischemia-Reperfusion Injury.

Cerebral ischemia-reperfusion injury significantly contributes to global morbidity and mortality. Loganin is a natural product with various neuroprotective effects; however, it lacks targeted specificity for particular cells or receptors, which may result in reduced therapeutic efficacy and an increased risk of side effects. To address the limitations of loganin, we developed LA-1, a novel compound incorporating an Arg-Gly-Asp (RGD) peptide to target integrin receptor αvβ3, enhancing brain-targeting efficacy. LA-1 exhibited optimal nanoscale properties, significantly improved cell viability, reduced ROS production, and enhanced survival rates in vitro. In vivo, LA-1 decreased infarct sizes, improved neurological function, and reduced oxidative stress and neuroinflammation. Proteomic analysis showed LA-1 modulates PI3K/Akt and Nrf2/HO-1 pathways, providing targeted neuroprotection. These findings suggest LA-1's potential for clinical applications in treating cerebral ischemia-reperfusion injury.

Adsorption of phenolic compounds by sodium alginate-modified starch nanoparticles in a multiphase system: kinetic, thermodynamic and release characteristics studies

Starch nanoparticles (SNPs) have been recognized as potentially efficient adsorbents for polyphenols. However, their actual adsorption in complex systems such as fruit pomace extract is significantly lower than theoretical predictions and their adsorption capacity is inferior to traditional materials such as macroporous adsorbent resins, which limits their industrial application. Aiming to enhance the adsorption of apple pomace polyphenols, this study used sodium alginate (SA) modifies SNPs to create a cornstarch-based composite system (SA-SNPs). The optimal modified addition of sodium alginate was 0.3 g (g starch)-1, under this condition, the nanoparticles obtained exhibited the smallest particle size (154.60 nm) and the best adsorption performance (33.97 mg g-1 in 90 min). The SA-SNPs reached the adsorption equilibrium at 180 min, which significantly enhanced the equilibrium adsorption amount of the polyphenols (from 2.68 to 37.02 mg g-1). The adsorption process was found to follow the pseudo-second- order kinetic model and the Langmuir isotherm model, which included membrane diffusion, intra-particle diffusion, and equilibrium phases. The adsorption amount initially increased and then continued to decrease with the increase in temperature, and the whole process was exothermic and spontaneous (ΔH° = -52.394 kJ mol-1, ΔG° < 0 kJ mol-1). Additionally, SA-SNPs loaded with polyphenols demonstrated better protection of polyphenol DPPH radical-scavenging activity during storage, enhanced stability, and optimal colon-targeted sustained-release properties in complex physiological environments. This work presents a new approach to improving the adsorption capacity of SNPs and developing high-performance natural edible separation materials.

Enhanced piezoelectric properties of BiFeO3-BaTiO3 lead-free ceramics by shifting phase boundary via simultaneous adjusting component and quenching technique

The morphotropic phase boundary (MPB) is particularly crucial for high piezoelectric performance of perovskite ferroelectrics. This study focus on the shift of MPB and its impacts on the piezoelectric properties of (1-x)Bi0.997La0.003FeO3-xBaTiO3 ferroelectric ceramic. Although appropriate La doping reduces leakage current, the phase boundary is moved towards tetragonal (T) phase. By adjusting BaTiO3 component, the concentration of rhombohedral (R) and T phase is restored back to almost equality at x = 0.295, achieving optimal piezoelectric properties (d33 = 179 pC/N, kp = 33.06%). Furthermore, through applying quenching on 0.30 ≤ x ≤ 0.32 samples occupied mainly by T phase, a higher d33 value of 205 pC/N and a remarkable amplification of d33 (about 40%) are both realized at x = 0.32, which is ascribed to the shift phase boundary close to 1:1. These results confirm the importance of phase boundary movement and provide an effective approach for performance enhancement of BiFeO3-BaTiO3 system.

Development of the magnetodielectric properties of BaTiO3-CoFe2O4 multiferroic composites

The lead-free x CoFe2O4 – (1-x) BaTiO3 (x= 0, 0.075, 0.15, 0.225, and 1) composites have been prepared via the solid-state process. The composites' microstructure, dielectric, ferroelectric, ferromagnetic, and magnetodielectric (MD) properties were investigated. Notably, XRD analysis indicates a decrease in the tetragonality factor (cT/aT) of the BTO phase, accompanied by an expansion of the unit cell as x increases from 7.5 to 22.5 wt.%. According to the FESEM images, the CoFe2O4 (CFO) grains are uniformly distributed in the matrix with the formation of no impurity phase. The optimal dielectric properties (dielectric constant (εr) ∼ 2018 and dielectric loss factor (tan δ) ∼ 0.16) and ferroelectric characteristics (saturation polarization (PS) ∼ 12 μC/cm2 and remnant polarization (Pr) ∼ 10 μC/cm2) are achieved at x=7.5 wt.%, attributed to the minimal presence of the non-ferroelectric CFO phase. By increasing the ferrite content (up to 22.5 wt.%), the ferroelectric properties of the samples showed a gradual diminution. Also, from x=7.5 to 22.5 wt.%, a sharp increase in the saturation magnetization (from 3.75 to 11.3 emu/g) and remnant magnetization (from 0.93 to 2.35 emu/g) values was observed, while the coercivity diminished from 475.8 to ∼ 272 Oe. The simultaneous observation of two ferroic characteristic hysteresis loops validated the multiferroicity of the composites (x=7.5, 15, and 22.5 wt.%). The maximum MD constant (4.68%) was measured for x=22.5 wt.% composite at the applied magnetic field of 7 kOe.

Optimisation of Additively Manufactured Coiled Flow Inverters for Continuous Viral Inactivation Processes

This article reports the development and utilisation of an adaptive design workflow methodology for use as a platform technology for the printing, testing, and optimisation of biopharmaceutical processing reactors. This design strategy was developed by application to the complex structure of the coiled flow inverter (CFI). In this way, the many possible physical parameters of the reactor were optimised, via a combination of experimental results, computational fluid dynamics and machine learning approaches, to find the CFI setups that provide the optimal flow properties for a particular application.Additively manufactured reactors are seeing increasing interest in the field of biopharmaceutical production. This is because the desired output volumes are typically small and there is an increasing move towards adopting continuous production, to replace traditional batch production. This approach allows for the tailoring of reactors for a specific reaction, i.e. attempting to maximise the desired aspects of the reaction through refinement of the physical parameters of the reactor, so creating a large possible parameter space to explore.Consequently, the holistic optimisation of CFI reactors and 3D printing is established as providing better plug flow mixing relative to traditional tube coiled reactors. In addition, a trained metamodel in combination with multilayer equations is demonstrated to predict reactor performance quickly and accurately.

Effects of Sn addition in W-doped Ag paste against electrochemical corrosion and sulfurization

Purpose This study aims to address these challenges by enhancing the resistance of Ag-based pastes to corrosion and sulfurization, thereby improving their performance and weatherability in high-power and high-frequency electronic applications. Design/methodology/approach This study investigates the influence of Sn doping in W-doped Ag paste to enhance resistance against electrochemical corrosion and sulfurization. A systematic examination was conducted using transient liquid phase sintering and solid–liquid inter-diffusion techniques to understand the microstructural and electrochemical properties. Findings This study found that Sn addition in W-doped Ag paste significantly improves its resistance to electrochemical corrosion and sulfurization. The sintering process at 600°C led to the formation of an Ag2WO4 phase at the grain boundaries, which, along with the presence of Sn, effectively inhibited the growth of Ag2WO4 grains. The 0.5% Sn-doped samples exhibited optimal anti-corrosion properties, demonstrating a longer grain boundary length and a passivation effect that significantly reduced the corrosion rate. No Ag2S phase was detected in the weatherability tests, confirming the enhanced durability of the doped samples. Originality/value The findings of this study highlight the potential of Sn-doped Ag-W composites as a promising material for electronic components, particularly in environments prone to sulfurization and corrosion. By improving the anti-corrosion properties and reducing the grain size, this study offers a new approach to extending the lifespan and reliability of electronic devices, making a significant contribution to the development of advanced materials for high-power and high-frequency applications.

The stir-frying process of Citrus reticulata ‘Chachi’: Process optimization, physical and chemical properties, and spectrum-activity relationship

To optimize the stir-frying process of Citrus reticulata ‘Chachi’ (CRC), analyze the physical and chemical properties and evaluate the activity. The best process condition was stir-frying temperature 110 ± 10 °C and time 25 min. The stir-frying Citrus reticulata ‘Chachi’ (SCRC) induced notable changes in the appearance and microstructure, enhancing its aroma and mellowness, reducing water content, and no aflatoxin was detected. It increased total flavonoids content. The ultra-high performance liquid chromatography fingerprints of SCRC and CRC showed 11 common peaks, seven compounds were identified by the retention time with the peak shapes of the Ultraviolet spectra. Through ABTS radical scavenging and α-glucosidase activity inhibition experiment, it was found that SCRC had stronger activity. The results of grey correlation analysis showed that peak 11 (tangeretin) was closely related to antioxidant activity, and peak 9 (nobiletin) was closely related to hypoglycemic activity. The analysis revealed that the components of antioxidant and hypoglycemic effects both overlapped and differed, suggesting a correlation between the two. The stir-frying process improved the product quality and activities and was conducive to its application and industrialization for simplicity and practicality, thus providing a scientific basis for natural plants to industrial products with the process technology.

The crystal structure, sintering characteristics and microwave dielectric properties of clinopyroxene SrBGe2O6 (B= Mn, Co) ceramics

Two novel low permittivity SrMnGe2O6 and SrCoGe2O6 ceramics with diopside structure were prepared by solid-state method, with their microwave dielectric properties reported for the first time. XRD and Rietveld refinement revealed that SrBGe2O6 (B = Mn, Co) ceramics belong to monoclinic system with C2/c space group. At lower sintering temperatures, SrBGe2O6 ceramics exhibit excellent relative density (> 94%). Compact SrMnGe2O6 and SrCoGe2O6 ceramics exhibit the best surface morphology, the highest relative density and the optimal microwave dielectric properties at 1100 °C and 1140 °C, respectively: εr = 8.71, Q×f = 30680 GHz, τf = − 60.32 ppm/°C; εr = 9.01, Q×f = 33335 GHz, τf = − 69.14 ppm/°C. The effect of intrinsic loss such as lattice vibration on the microwave properties of SrBGe2O6 ceramics was studied by Raman spectroscopy. An analysis based on lattice vibration elucidates the reasons behind the differences in microwave properties between the two ceramics. Furthermore, the correlation between Q×f value and sintering temperature was analyzed with covalent bond strength, and the relationship between structure and temperature stability was discussed by octahedral distortion. Study on these two novel ceramics not only broaden the system of microwave dielectric ceramics, but also provide new materials for the construction of communications technology.

Thermoelastic behavior analysis of finite composites embedded in ellipsoidal inhomogeneities with inclusion-based boundary element method

The thermoelastic properties of composites play a pivotal role in various practical engineering challenges. This paper employs the inclusion-based boundary element method (iBEM) to analyze the thermoelastic field and predicts the influence of key parameters in the particle phase on composite properties. Utilizing the equivalent inclusion theory, material mismatch effects are characterized by eigenstrain and eigen-temperature gradient. Incorporating the boundary integral equation, the boundary effects are addressed, which facilitates the computation of internal field outcomes via stress and heat flux equivalent conditions. Validation against finite element and experimental data confirms the efficacy of iBEM in accurately simulating thermoelastic behavior and predicting effective properties of particle composites. Noteworthy findings indicate that optimal composite properties align with the long axis orientation of ellipsoidal particles, while the particle distribution significantly impacts the effective Poisson’s ratio.

Quick-Delivery Mold Fabricated via Stereolithography to Enhance Manufacturing Efficiency.

The ever-growing demand for reducing costs and decreasing the time to market in today's plastics industry makes rapid tooling and rapid prototyping highly researched areas. Stereolithography (SLA)-manufactured injection mold inserts make it possible to produce prototype parts rapidly and cost-effectively. To utilize SLA in the injection molding industry, two steps have to be considered. The first is to identify suitable SLA process and post-thermal curing process parameters to enhance the mechanical and thermal characteristics. The second is to verify the applicability of SLA-manufactured molds for use in the injection molding industry. IA comprehensive study was performed to find the optimum process parameters for an SLA mold with excellent mechanical and thermal properties and to verify the applicability of the mold. First of all, the mechanical and thermal properties of samples manufactured based on various laser powers and heat treatment at different temperatures were analyzed with a tensile test, DSC, and TMA according to the degree of cure. On the basis of the results from those tests, an SLA mold was designed and fabricated with the optimum mechanical and thermal properties. In addition, the SLA mold was assembled into an injection machine, and an injection molding test was conducted. The SLA mold endured during the injection cycle, and 500 shots were successfully injected without damaging the mold, which resulted in reaching the quick-delivery mold standard. Finally, we demonstrate that SLA is an effective technology to produce molds for use in the injection molding industry.

Microstructure and Mechanical Properties of Laser Powder Bed Fusion 3D-Printed Cu-10Sn Alloy

This study investigated the optimal process conditions and mechanical properties of Cu-10Sn alloys produced by the powder bed fusion (PBF) method. The optimal PBF conditions were explored by producing samples with various laser scanning speeds and laser power. It was found that under optimized conditions, samples with a density close to the theoretical density could be fabricated using PBF without any serious defects. The microstructure and mechanical properties of samples produced under optimized conditions were investigated and compared with a commercial alloy produced by the conventional method. The hardness, maximum tensile strength, and elongation of the samples were significantly higher than those of the commercially available cast alloy with the same chemical composition. Based on these results, it is expected to be possible to use the PBF technique to manufacture Cu-10Sn products with complex 3D shapes that could not be made using the conventional manufacturing method.

Evolution of Microstructures and Mechanical Properties with Tempering Temperature in a Novel Synergistic Precipitation Strengthening Ultra-High Strength Steel.

The evolution of microstructures and mechanical properties with tempering temperature of a novel 2.5 GPa grade ultra-high strength steel with synergistic precipitation strengthening was investigated. With increasing tempering temperature, the experimental steel initially progressed from ε-carbides to M3C and then to M2C, followed by further coarsening of the M2C carbides and β-NiAl. Concurrently, the martensite matrix gradually decomposed and austenitized. The ultimate tensile strength and yield strength initially increased and subsequently decreased with rising tempering temperature, reaching peak value at 460 and 470 °C, respectively. Conversely, the ductility and toughness initially decreased and then increased with rising tempering temperature, reaching a minimum at 440 °C. The increase in strength was attributed to the secondary hardening effects resulting from carbide evolution and the precipitation of β-NiAl. The subsequent decrease in strength was due to the recovery of martensite and coarsening of precipitates. The decrease in ductility and toughness was linked to the precipitation of M3C, while their subsequent increase was primarily attributed to the dissolution of M3C and an increase in the volume fraction of reverted austenite. The high dislocation density of martensite, the film of reverted austenite, nanoscale M2C carbides, and ultrafine β-NiAl obtained during tempering at 480 °C resulted in the optimal mechanical properties of the experimental steel. The strength contributions from M2C carbides and β-NiAl were 1081 and 597 MPa, respectively.

Extrusion Parameters Optimization and Mechanical Properties of Bio-Polyamide 11-Based Biocomposites Reinforced with Short Basalt Fibers.

The increasing demand for sustainable materials in high-value applications, particularly in the automotive industry, has prompted the development of biocomposites based on renewable or recyclable matrices and natural fibers as reinforcements. In this context, this paper aimed to produce composites with improved mechanical and thermal properties (tensile, flexural, and heat deflection temperature) through an optimized process pathway using a biobased polyamide reinforced with short basalt fibers. This study emphasizes the critical impact of fiber length, matrix adhesion, and the variation in matrix properties with increasing fiber content. These factors influence the properties of short-fiber composites produced via primary processing using extrusion and shaped through injection molding. The aim of this work was to optimize extrusion conditions using a 1D simulation software to minimize excessive fiber fragmentation during the extrusion process. The predictive model's capacity to forecast fiber degradation and the extent of additional fiber breakage during extrusion was evaluated. Furthermore, the impact of injection molding on these conditions was investigated. Moreover, a comprehensive thermomechanical characterization of the composites, comprising 10%, 20%, and 30% fiber content, was carried out, focusing on the correlation with morphology and processing using SEM and micro-CT analyses. In particular, how the extrusion process parameters adopted can influence fiber breakage and how injection molding can influence the fiber orientation were investigated, highlighting their influence in determining the final mechanical properties of short fiber composites. By optimizing the process parameters, an increment with respect to bio-PA11 in the tensile strength of 38%, stiffness of 140%, and HDT of 77% compared to the matrix were obtained.

Experimental evaluation and simulation of myoblast cell alignment on the UV-irradiated liquid crystalline elastomers as a versatile tissue-engineered Scaffolding material

Efforts to develop versatile tissue-engineered scaffolds mimicking the functions of extracellular matrices (ECMs) have led to the emergence of liquid crystalline elastomers (LCEs) as promising materials. Here, thiol-acrylate-based LCEs forming a nematic phase upon UV irradiation were synthesized, and their biological compatibility was evaluated using C2C12 myoblast cells. Prior to UV exposure, some characteristics, e.g., phase transition temperature (TNI), order parameter, and reaction time, of the as-synthesized LCEs are characterized for property optimization. Fourier-transform infrared spectroscopy revealed that thiol-acrylate Michael addition polymerization was successful, judged by the disappearance of the characteristic peaks of thiol and acrylate groups. Differential scanning calorimetry thermograms and dynamic mechanical thermal analysis curves showed TNI values at ca. 49 °C, at which point the nematic phase is the dominant morphology. Moreover, the cross-linking density, the fixing, and the recovery ratios for the sample with optimal properties (i.e., LCE3) were determined to be 10.3 mol/cm3, 97.2 % and 91 %, respectively. Assessment of mesomorphism and roughness demonstrated the suitability of LCE3 for cell culture. Subsequent studies on adhesion, viability, differentiation, and proliferation of cultured myoblast cells, coupled with particle image velocimetry simulation, highlighted the potential of UV-irradiated LCE3 as a promising scaffold material for inducing surface morphology-induced cellular alignment and interactions.

Enhancing Mechanical and Tribological Properties of Epoxy Composites with Ultrasonication Exfoliated MoS2: Impact of Low Filler Loading on Wear Performance and Tribofilm Formation.

This study highlights the impact of low amounts of MoS2 quantities on composite performance by examining the effects of ultrasonication exfoliated MoS2 at different loadings (0.1-0.5 wt%) on the mechanical and tribological parameters of epoxy composites. Even at low concentrations, the ultrasonication and exfoliation procedures greatly improve the dispersion of MoS2 in the epoxy matrix, enabling its efficient incorporation into the tribofilm during sliding. Optimum mechanical properties were demonstrated by the MoS2/epoxy composite at 0.3 wt%, including a modulus of elasticity of 0.86 GPa, an ultimate tensile strength of 61.88 MPa, and a hardness of 88.0 Shore D, representing improvements of 61.5%, 35.45%, and 16.21%, respectively. Corresponding tribological tests revealed that high sliding velocity (10 N load, 0.2 m/s) resulted in a 44.07% reduction in the coefficient of friction and an 86.29% reduction in wear rate compared to neat epoxy. The enhanced tribological performance is attributed to the efficient removal and incorporation of MoS2 into the tribofilm, where it acts as a solid lubricant that significantly reduces friction and wear. Even though an ultra-low amount of filler concentration was added to the composite, a unique finding was the high MoS2 content in the tribofilm at higher sliding speeds, enhancing lubrication and wear protection. This study establishes that even ultralow MoS2 content, when uniformly dispersed, can profoundly improve the mechanical and tribological properties of epoxy composites, offering a novel approach to enhancing wear resistance.

A Novel Elastomeric Dielectric Materials: Natural Rubber/Copper-Modified Activated Carbon

In this research, a new elastomeric dielectric material is created by integrating natural rubber (NR) with activated carbon derived from coconut shells that has been modified with copper (Ac-Cu). Here, The copper content, ranging from 0 to 2%, was meticulously examined on the AC surface through a reduction technique from copper (II) to copper (0), with the Ac-Cu concentration fixed at 15 parts per hundred of rubber (phr). Systematic investigations into the effects of the additive were conducted across various parameters, encompassing optimum curing time (t90), density, crosslink density, mechanical properties, morphology, and dielectric properties. Results revealed a notable influence of copper on the curing process, resulting in decreased cure time, and a corresponding decrease in crosslink density as the copper content increased. Interestingly, copper incorporation demonstrated a positive impact on mechanical properties. Dielectric property analysis further confirmed a direct effect of increasing copper content on the frequency range of 0.85 to 1.15 GHz. This work not only introduces a pioneering dielectric material but also provides crucial insights into the nuanced effects of copper modification, offering avenues for tailored material design in the realm of enhanced dielectric applications.

MICROSTRUCTURE AND WEAR BEHAVIOR CHARACTERIZATION OF STIR-CAST ALUMINUM 6063 ALLOY AND ITS FOAM: A COMPARATIVE STUDY

In this research work, aluminum 6063 alloy foam was synthesized through stir casting using varying amounts of titanium hydride as a foaming agent. A comparative microstructural and wear behavior analysis of stir-cast aluminum 6063 alloy and its foam is presented. The oxide and aluminide phases present as intermetallic compounds in the stir-cast aluminum 6063 alloy foam ensure the stability of the synthesized foam. In order to optimize the effect of wear parameters on the tribological properties of stir-cast aluminum 6063 alloy foam, the L933 orthogonal array (OA) was designed and modeled statistically. The tribological properties of stir-cast aluminum 6063 alloy and its foam were evaluated by pin-on-disc tests. The optimal tribological properties of the synthesized foam are 0.29 coefficient of friction, 8.6 N frictional force, and 0.00025 mm3/N-m specific wear rate. The tribological properties of stir-cast aluminum 6063 alloy foam are superior to those of aluminum 6063 alloy and comparable to other aluminum foams described in the literature.