International Journal of Mechanical and Materials Engineering最新文献

This study presents a simple co-precipitation method for a ternary composite integrating zinc oxide (ZnO), sulfanilic acid (SA) and graphene oxide (GO). Sulfanilic acid serves a dual role as a molecular linker and structural spacer, enabling uniform anchoring of ZnO nanoparticles onto GO sheets and preventing agglomeration. X-ray diffraction (XRD) revealed phase-pure hexagonal ZnO and partial ordering in GO. Raman spectroscopy confirmed the presence of distinct D and G bands, along with strong π–π stacking interactions, suggesting good integration of the carbon framework. X-ray photoelectron spectroscopy (XPS) provided evidence of N–Zn coordination and hydrogen bonding between sulfonic (S = O) and hydroxyl (H–O–Zn) groups, indicating successful chemical interactions at the interface. FTIR spectra further supported this by revealing characteristic peaks corresponding to amine and sulfonic acid functionalities. Preliminary electrochemical evaluation via cyclic voltammetry and impedance spectroscopy in 1 M NaOH revealed capacitive behavior, suggesting potential for further optimization toward energy storage applications.

Graphical Abstract

The objective of this study was to develop ecofriendly graphene nanoplatelet (GNP)/polymer films with high electrical conductivity and excellent electromagnetic interference (EMI) shielding performance. We have shown that three-roll milling could produce thin graphite platelet with 6–7 nm in thickness using carboxymethyl cellulose (CMC) as exfoliation agent. A large-area film with oriented exfoliated graphite could be produced by doctor-blade method. In order to maximize the electrical conductivity and EMI properties (0.5–18 GHz) of exfoliated graphite film, the number of passes, graphite particle size, and binder were investigated. It was found that films fabricated with poly(acrylic acid)(PAA) as a binder exhibited high electrical conductivities of up to 773 S/cm owing to doping effects of PAA. In contrast, CMC-based films demonstrated superior EMI shielding, reaching 29.9dB and 1169 dB/mm, which was attributed to the enhanced GNP exfoliation and in-plane orientation. We confirmed that films using graphite exfoliated by a roll mill exhibited superior electrical conductivity and EMI properties to films using commercially available GNPs. Our proposed method is suitable for mass production of high quality GNP, and allows the production of GNP films with low energy and low cost.

In this study, SrO-MgO nanocomposites (NCs) were synthesized using the sol–gel method. SrO-MgO NCs with varying SrO concentrations (1, 3, 5, and 7 atomic weight %) were synthesized and systematically investigated for their structural, optical, and gas-sensing properties. Field Emission Scanning Electron Microscopy (FESEM) revealed a highly porous and agglomerated morphology. Energy Dispersive X-ray Spectroscopy (EDS) confirmed the elemental composition with Sr, Mg, and O, validating the successful incorporation of SrO into the MgO matrix. X-ray diffraction (XRD) confirmed the crystalline nature of the composites and the cubic phase of MgO with SrO incorporation, as evidenced by peak shifts and changes in crystallite size. Fourier Transform Infrared Spectroscopy (FTIR) reveals the broad absorption peaks observed in the 400–600 cm^-1 region corresponding to the Mg–O and Sr–O stretching vibrations. The optical properties were analyzed using UV–VIS spectroscopy. The bandgap energies were determined using Tauc’s plot, showing an increase from 3.61 eV (1% SrO) to 3.76 eV (7% SrO) with increasing SrO content. This variation in bandgap suggests a variation in lattice structure due to SrO incorporation. The gas sensing characteristics were evaluated against H₂S, NO₂, CO₂, NH₃, CH₄, and LPG over a 40–200 °C. The sensitivity studies revealed an optimum operating temperature of 120 °C, where the 7% SrO-MgO NCs exhibited the highest sensitivity (~ 83.11%), particularly toward H₂S gas. The enhanced gas sensing performance was attributed to increased oxygen vacancies, improved charge carrier mobility, and modified surface states induced by SrO doping. The obtained results suggest that SrO-MgO NCs, particularly 7% doping concentration of SrO, have significant potential for applications in toxic gas detection due to their high sensitivity, selectivity, and quick response and recovery time.

Graphical Abstract

This research investigates the influence of cryogenic treatment parameters on the mechanical performance of polybutylene terephthalate (PBT) and polycarbonate (PC) blends. Using Grey Relational Analysis (GRA), a multi-response optimization technique, the study explores how varying blend ratios (70/30, 50/50, and 30/70) and cryogenic soaking durations (4–24 h at − 185 °C) affect tensile strength, elongation, impact strength, Shore D hardness, and specific wear rate. Experimental results reveal that each blend ratio responds uniquely to cryogenic treatment, emphasizing the need for parameter-specific optimization. Notably, the 70/30 blend ratio with a 16-h soaking period demonstrated the most balanced enhancement across all properties, as indicated by the highest Grey Relational Grade (GRG). The findings provide critical insights for optimizing the processing of PBT/PC blends in applications demanding high durability, toughness, and wear resistance.

Graphical Abstract

This study aims to evaluate and compare the mechanical performance of hemp and corn husk fibers as natural reinforcements in a polymer blend matrix composed of 80% epoxy and 20% polycarbonate (PC). Composite samples were fabricated using the hand layup technique with varying fiber loadings of 2%, 4%, and 6% for each fiber type. Mechanical characteristics such as impact strength, fracture toughness, and tensile strength, Young’s modulus, and hardness were measured to assess the influence of fiber type and content. Results showed that corn husk fiber composites exhibited superior fracture toughness (up to 120.38 MPa·m^1/2 at 6%) and Young’s modulus (0.97 GPa at 6%) compared to hemp fiber composites, while both showed comparable hardness (77 HRF at 2%). SEM analysis confirmed strong interfacial adhesion between the natural fibers and the polymer matrix. Overall, the study demonstrates that corn husk fibers, despite being underutilized, offer promising reinforcement potential and can outperform conventional hemp fibers in certain mechanical aspects.

AgI-МСМ48-MeI_x hybrid powders (HPs) were prepared by the method of Hydrothermal template co-condensation. Silver iodide was always a product of the reaction between silver nitrate and potassium iodide. But metal iodide (copper iodide or zinc iodide) was a native substance or a result of the reaction between metal nitrate and potassium iodide. There were 2 ways to form metal iodides in the reaction solution. The effect of the metal iodide form (nitrate or iodide one) on the structural, textural, morphological, and rheological properties of the HPs has been studied. Much attention was paid to the thermal stability of silver iodide in the hybrids with the introduction of additional iodine donors - copper iodide or zinc iodide (through their nitrate or iodide form). It has been shown that the nitrate form of metal iodide (regardless of the type of cation) makes it possible to preserve the development of the powder agglomerate surface to a greater extent. It is noted that when using zinc iodide as an iodine donor, the amount of silver iodide in the hybrid composition was greater than with copper iodide or in the complete absence of an iodine donor.

The advancement of nanocomposite hydrogels with superior mechanical robustness, tunable swelling, and rheological performance is pivotal for next-generation biomedical and industrial systems. In this work, a novel gum acacia-grafted poly(N,N-dimethylacrylamide) (GA-g-PDMAAm) hydrogel reinforced with cobalt ferrite (CF/CoFe₂O₄) nanofillers was synthesized via free-radical graft copolymerization. CoFe₂O₄ nanoparticles (average crystallite size: 8.32 nm, calcined) were fabricated through chemical co-precipitation and homogeneously embedded into the hydrogel network, imparting enhanced structural integrity, magnetic responsiveness, and thermal stability. FTIR, XRD, FE-SEM, and TGA analyses confirmed efficient grafting, crystalline dispersion, and improved thermal resistance, with weight loss at 450 °C reduced from 72.24 to 59.58% and an onset degradation temperature near 150 °C. Rheological studies revealed shear-thinning pseudoplasticity, storage modulus (G′) dominance over loss modulus (G″) across 0.1–100 rad s⁻¹, and damping factors (tan δ) below 0.3, indicating elastic-dominated behavior. Thermal sweeps showed modulus stability up to 35 °C, particularly in high CoFe₂O₄-loaded networks. Mechanical testing identified GADMACF-10 as exhibiting maximal shear stress under 25% strain, while swelling capacity increased from 9.78 g g⁻¹ to 13.85 g g⁻¹ (~ 41.6% enhancement) at optimal filler loading (GADMACF-50). These findings position GA-g-PDMAAm/CoFe₂O₄ nanocomposites as multifunctional, mechanically resilient, and highly absorbent materials suited for wound healing, drug delivery, and tissue engineering applications.

Red anthill clay (RAC) sample from a deposit in Kataeregi, Niger State, Nigeria, was examined for its mineralogical, geochemical, and physicochemical properties, as well as its industrial potentials. The collected sample was prepared and analysed for particle size distribution, moisture content, bulk density, Energy Dispersive X-ray fluorescence (ED-XRF), and X-ray diffractometry (XRD). Results revealed that RAC contains 63.19% silica, and 17.71% alumina, with kaolinite as the dominant clay mineral alongside quartz, feldspar, and goethite. The clay exhibited a bulk density of 1.33 g/cm³ and an apparent porosity of 49.8%, that indicates its high adsorption capacity. Particle size analysis showed 38.7% fines passing through a 0.075 mm sieve. Compressive strength tests on RAC bricks demonstrated increasing strength with curing time (2.09–5.32 MPa for unfired bricks; 8.19–10.35 MPa for fired bricks at 900–1200 ℃), while thermal shock resistance tests indicated durability up to 23–28 cycles at 900–1100 ℃. These properties suggest RAC’s suitability for insulating firebricks, even though its high porosity limits high load-bearing structural applications. Further modifications are needed to enhance performance for broader uses, such as ceramics, refractories, and adsorption-based remediation in contaminated aqueous solutions.

Voids in electroless copper (Cu) plating layers critically influence the reliability of microvias in high-density interconnect (HDI) packaging substrates. This study investigates void formation mechanisms by fabricating multilayered Cu structures that simulate microvia interconnections and performing electroless Cu plating under controlled nickel (Ni) ion concentrations and bath temperatures. Void morphology and distribution are analyzed using transmission electron microscopy (TEM) and quantitative image analysis. The results reveal that increased Ni content and elevated bath temperatures accelerate the plating rate, thereby promoting void formation at the initial stage of deposition. Theoretical analysis suggests that this behavior is driven by surface cohesion forces acting on nascent voids. A void growth mechanism is proposed, wherein voids predominantly originate within the initial Cu layer due to localized hydrogen accumulation near palladium (Pd) catalysts. In contrast, subsequent layers—deposited after Pd sites are buried—exhibit reduced maximum (max.) void sizes and lower void fractions. These findings provide mechanistic insight into void evolution in electroless Cu layers and underscore the critical role of Ni content and bath temperature in enhancing HDI packaging substrate reliability.

Tool vibration and acoustic studies in the face milling of AISI 1045 steels are essential for ensuring high-quality surface finishes, prolonging tool life, maintaining machining stability, operational continuity, and optimizing manufacturing efficiency. These studies contribute to better process control, cost savings, and the overall reliability of the machining operations. In this work spindle speed, feed rate, and depth of cut were considered as machining parameters and tool vibration, and acoustics were considered as responses. Three levels for the parameters were selected, and using Minitab 18 software, 27 trials were generated and experiments were carried out to get the responses. Using Abaqus a numerical model was developed to find the modes of natural frequencies. Then Fast Fourier Transforms to convert the vibration and acoustic characteristics from the time domain to the frequency domain to determine the amplitude closest to the natural frequency of tool vibration and acoustic emission. For the multi-objective optimization, Response Surface Methodology was used to get the optimal combination of machining parameters. Confirmation experiments were carried out at the optimal combinations and the model is well validated.