Solid State Phenomena Vol. 392

Abstract: The automobile industry's increasing need for lightweight, high-performance materials has brought attention to Al-Si-Cu die-cast alloys, which face significant challenges, including porosity-induced defects, galvanic corrosion, and environmental degradation. Traditional chromate-based coatings, while effective, are being phased out due to toxicity and regulatory restrictions under REACH and RoHS. This review evaluates cutting-edge bio-inspired and self-healing coatings as sustainable alternatives to enhance the durability and corrosion resistance of Aluminum alloys. Key innovations include micro/nanocontainer-based inhibitor release systems, LDHs (layered double hydroxides) for on-demand corrosion suppression, and superhydrophobic composites mimicking lotus-leaf topographies. We critically evaluate the performance of these coatings using electrochemical (EIS, SVET) and non-electrochemical (SEM, XRD) techniques, emphasizing their efficacy in mitigating micro-galvanic corrosion caused by the heterogeneous microstructure of aluminum. Challenges such as scalability, mechanical durability, and cost-effectiveness are discussed, alongside emerging trends like graphene-enhanced barriers and bio-based polymers (e.g., phosphorylated chitosan). By bridging material science with bio-inspired design, this review provides a roadmap for developing eco-friendly, high-performance coatings tailored to automotive applications, ensuring compliance with environmental regulations while extending component lifespan under harsh operating conditions.

Abstract: The current research work analysis the surface plasmons produced in the bimetallic thin films. The study aimed to understand the nature of surface plasmons produced from single metal thin film of copper and then to investigate the effect of addition of another metal thin layer above it. The research work was carried out via simulation analysis using Kretschmann-Raether configuration. Angular interrogation method and wavelength interrogation method was used to optimize the surface plasmon response from copper thin film in the nanometer range. On the optimized film of copper, another thin layer of gold and silver was added and nature of surface plasmons produced was analyzed. The results show better SPR response from Cu-Au and Cu-Ag bimetallic thin films than using single metal films. The reflected light intensity in the SPR response shows a drastic reduction from 15% to 5% for bimetallic Cu-Au thin film and to 2% for Cu-Ag thin film. The FWHM measurements also displays the reduction from 0.7724^o for Cu monometallic film to 0.4319^o for Cu-Au bimetallic films and 0.2460^o for Cu-Ag bimetallic thin film. The results obtained from this analysis certainly benefits the optical sensor applications in medical and biological fields.

Abstract: An embedded system-based spin coating machine has been developed to grow thin films. Pure zinc oxide (ZnO) and magnesium-doped zinc oxide (ZnO: Mg) thin films with different doped samples have been prepared using the spin coating technique for LPG gas sensing application. The spin coating machine is fully controlled by a PIC microcontroller (PIC16f877A), which can drive a driver circuit to drive a spinning motor, and ZnO: Mg thin films are deposited using this machine. XRD results indicated that the movie has a hexagonal wurtzite structure with a preferred orientation, and the crystallite size increases with the increasing doping concentration of Mg. The surface morphology investigation shows that grains are irregular in shape, and doping concentrations do not influence the surface morphology. From the TEM image, particle sizes observed ranged between 23 and 28 nm, with an average value of ~25.8 nm. The maximum visible average transmittance was 96% for an optimum Mg doping concentration of 10 wt% %. The investigated DC electrical conductivity of Mg-doped ZnO thin films shows enhanced electrical conductivity compared to pure ZnO, and the AC conductivity is decreased with increasing Mg doping concentrations from 5 to 10 wt%. The operation and sensing mechanism of Pure ZnO and ZnO: Mg thin films behind their impressive results has been studied in depth.

Abstract: In the cosmetics packaging industry, UV coating is applied to enhance surface characteristics by providing scratch resistance, a glossy finish, stain resistance, and improved durability against environmental exposure. UV coating is a curing process that utilizes ultraviolet (UV) lamp radiation. This process is influenced by several parameters, including conveyor speed, UV lamp temperature, and the distance between the UV lamp and the product. However, in the current packaging process, these parameters are often set based on routine practices rather than standardized guidelines. As a result, improper UV curing can lead to cracking defects that appear after the product assembly stage. These cracks are caused by suboptimal UV exposure during the curing process, which compromises the mechanical integrity of the product. This paper intends to determine the appropriate standard temperature settings based on a comparative analysis of UV lamp temperatures and distances. Experiments were conducted using four UV lamps with temperature settings of 50°C, 75°C, and 100°C, repeated across five trials. The results show improved mechanical properties and a significant reduction in cracking defects. Furthermore, the findings support the development of more efficient and standardized settings for the UV curing process.

Abstract: A typical Nebulizer Spray Pyrolysis (NSP) technology was used to produce and deposit CuO nanoparticles on glass substrates. In this work, the effects of different precursor volumes on the properties of CuO thin films produced by Nebulizer Spray Pyrolysis (NSP) were investigated. In this work, CuO thin films have been developed using the NSP approach with three different precursor quantities (3, 4, and 5 ml). A monoclinic crystal structure was found using X-ray diffractometry (XRD), which was confirmed to be consistent with JCPDS card No. (89-5899). The XRD studies have been used to calculate the dislocation density, micro strain, and crystallite size. The average thickness was measured using a surface profilometer. High-resolution Schottky emitter FE-SEM has been used to study morphological properties, and the results demonstrate that each film has been evenly deposited on the glass substrate. The presence of the element in the CuO thin films has been confirmed by energy dispersive X-ray analysis (EDAX). Transmission values ranging from 20% to 65% at varied volumes were achieved, according to the optical measurements. The energy band gaps were determined using tauc plots to be between 1.85 eV and 2.15 eV, with 4 ml having the lowest band gap value at 1.85 eV. CuO thin-film’s electrical conductivity was measured in DC, and the highest conductivity value for 4ml was 2.5x10^-8 S/cm.

Abstract: Pantograph slide materials demand excellent mechanical and electrical properties for rail applications. Carbon-copper (C-Cu) composites combine the high electrical conductivity of copper with lightweight and wear-resistant traits of carbon. Using palm kernel shells (PKS), a palm oil industry by-product, promotes sustainability but presents challenges in achieving uniform distribution and performance retention. This study examined PKS and graphite as carbon sources in C-Cu composites enhanced with carbon nanotubes (CNT), focusing on optimising mechanical and electrical properties for pantograph slides. However, CNT is known for its difficulty in achieving optimum dispersion in composites, as strong van der Waals forces cause aggregation, uneven distribution, and porosity, thereby reducing the electrical and mechanical properties. Balancing carbon content, CNT reinforcement, copper, and resin matrix is crucial to prevent conductivity loss and structural weaknesses. Varied CNT content (1wt% to 5wt%) was analysed for its impact on hardness, transverse rupture strength (TRS), and electrical resistivity of the C-Cu composite. Fabrication involved material mixing, cold pressing, warm compaction (150°C, 490 kN, 5 minutes), and post-baking process (250°C, 4 hours). The 2 wt% CNT sample achieved superior results, including 102.5 HRR hardness, 37.63 MPa TRS, and 32 µΩ.m resistivity before post-baking, due to excellent CNT dispersion. Post-baking enhanced bonding and mechanical properties but raised resistivity by altering conductive pathways. Poor dispersion of CNT at contents more than 3 wt% led to agglomeration and inferior properties. The findings highlight the critical role of CNT dispersion and the post-baking process in achieving optimal composite performance to maximise CNT potential. These results are comparable to commercial pantograph slides, contributing to the development of high-performance materials for rail applications.

Abstract: Composites are materials designed to achieve superior mechanical or physical properties, and understanding both their failure and dynamic behavior is essential. Despite numerous past studies on understanding this behavior of composite materials, information on the interrelationship between these two aspects remains limited. The study aims to conduct a process innovation and provide detailed understanding of the effect of fiber orientation on the Graphite epoxy and E-glass epoxy composite laminates failure behavior and natural frequency and the relationship between the failure and dynamic behavior of these two materials. To achieve this, a process innovation of the simulation of failure analysis and vibration analysis of these composite laminates under uniaxial tensile loading was conducted on 8-ply composite laminates under a lamination scheme of (-θ/45/-45/θ/-θ/45/-45/θ), where θ from 0° to 90°. Finite element models for simulation were developed and validated to ensure the reliability and validity of findings in this study are trustworthy and useful. The results show that both failures loads, and natural frequencies are not much affected by the fiber orientation under this lamination scheme. These two behaviors are also identified to be closely related under specific modes of natural frequency. The detailed effects of failure and natural frequency under fiber orientation and its relation are successfully acknowledged. The findings are expected to support the optimization of laminate design and enhance the structural performance of composite materials in engineering applications and contribute to more informed material selection.

Abstract: Hybrid composite laminates that combine Kevlar and glass fibers offer tailored performance, but the interaction between their progressive failure and vibrational behavior remains insufficiently understood. This study employs finite element analysis in ANSYS APDL to evaluate Kevlar/epoxy, glass/epoxy, and Kevlar–glass hybrid laminates with cross-ply and angle-ply stacking sequences, using layered shell elements and the Maximum Stress criterion. The study validates the model against published experimental data and applies it to assess first-ply failure (FPF), last-ply failure (LPF), and natural frequencies. Results show that Kevlar laminates provide the highest strength and natural frequencies, while glass laminates exhibit the lowest, with hybrids consistently demonstrating intermediate performance. Although hybrids record lower FPF than either constituent, their LPF exceeds that of GFRP, reflecting beneficial stress redistribution during damage progression. Natural frequencies decrease systematically with increasing fiber angle, with Mode 2 showing greater sensitivity to orientation. Among the hybrids, H4 provided the most balanced overall performance, pairing competitive LPF with stable modal behavior. This study establishes a clear correlation between failure progression and dynamic response, highlighting the governing role of fiber content and stacking sequence in determining the structural integrity and vibration resistance of hybrid laminates.

Abstract: Industrial wastewater often contains colored toxic dyes and heavy metals that harm ecosystems and human health, highlighting the need for sustainable treatment strategies. This study aimed to develop a guar gum (GG)/polyacrylamide (PAAm)/rice straw biochar (RSBC) hydrogel grafted onto polyethylene terephthalate (PET) (GG/PAAm RSBC-g-PET) textile, and its structure was characterized through swelling behavior, FTIR-ATR spectroscopy, and Scanning Electron Microscopy (SEM) analysis. The modified GG/PAAm/RSBC-g-PET exhibits a significant increase in water absorption compared to GG/PAAm-g-PET. The alteration and shifted peaks were observed particularly at bands of 3441 cm^-1 (RSBC), and 852 cm^-1 (galactose and mannose units), imparting effective crosslinking. SEM analysis revealed a porous structure with irregular magnetite particles, enhancing the active surface area. The performance of the GG/PAAm/RSBC-g-PET composite was evaluated using industrial wastewater, which resulted in reduced turbidity (26.5 NTU) and color (~49.5 ADMI), compared to filtration with PET textile alone (47 NTU and ~69.5 ADMI). The GG/PAAm/RSBC-g-PET composite exhibits comparable yet inconsistent improvements, possibly due to particle release and pore blockage. These findings demonstrate the feasibility of the GG/PAAm/RSBC-g-PET textile for decolorization, indicating its potential application in wastewater remediation.