As the use of aluminum structures grows due to their lightweight properties and sustainability advantages, optimizing bonding technologies is essential for ensuring strong and durable joints. This study systematically evaluates fourteen surface treatment methods applied to aluminum sheets and L-section joints, assessing their influence on adhesion performance. Surface preparation significantly impacted bond strength. Veil sanding combined with Sika® Primer-207 led to an 82 % increase in tensile strength and a 258 % increase in shear strength compared to untreated surfaces. Laser and hot deionized water treatments resulted in the highest measured surface energy (88 mN/m), improving wettability and adhesive-substrate interaction. To analyze bonding performance, a flexible polyurethane adhesive was applied to structural joints, which were tested under tensile and shear stress conditions. The results demonstrated that surface roughness, free energy, and chemical modification strongly influence failure modes. While untreated surfaces predominantly exhibited adhesive failure, optimized treatments shifted failure toward cohesive failure, indicating a stronger interfacial bond. Additionally, the correlation between surface free energy, surface roughness, and adhesive strength was examined to understand their combined effects on joint performance. The findings highlight the importance of selecting appropriate surface modification techniques to maximize adhesion and joint durability. This research provides practical insights for industries relying on aluminum bonding, offering guidance on optimizing surface treatment protocols to enhance structural integrity and long-term reliability in demanding applications.

This study investigates the hydrogen permeability of injection-molded polyamide 6 (PA6) nanocomposites reinforced with organo-modified montmorillonite (OMMT) at varying concentrations (1, 2.5, 5, and 10 wt. %) for potential use as Type IV composite-overwrapped pressure vessel (COPV) liners. While previous work examined their mechanical properties, this study focuses on their crystallinity, morphology, and gas barrier performance. The precise inorganic content was determined using thermal gravimetry analysis (TGA), while differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and scanning electron microscopy (SEM) were used to characterize the structural and morphological changes induced by varying filler content. The results showed that generally higher OMMT concentrations promoted γ-phase formation but also led to increased agglomeration and reduced crystallinity. The PA6/OMMT-1 wt. % sample stood out with higher crystallinity, well-dispersed clay, and low hydrogen permeability. In contrast, the PA6/OMMT-2.5 and -5 wt. % samples showed increased permeability, which corresponded to WAXD and SEM evidence of agglomeration and DSC results indicating a lower degree of crystallinity. PA6/OMMT-10 wt. % showed the most-reduced hydrogen permeability compared to all other samples. This improvement, however, is attributed to a tortuous path effect created by the high filler loading rather than optimal crystallinity or dispersion. SEM images revealed significant OMMT agglomeration, and DSC analysis confirmed reduced crystallinity, indicating that despite the excellent barrier performance, the compromised microstructure may negatively impact mechanical reliability, showing PA6/OMMT-1 wt. % to be the most balanced candidate combining both mechanical integrity and hydrogen impermeability for Type IV COPV liners.

Today, the automotive industry is undergoing rapid change. While manufacturers are constantly switching to fully or semi-electric hybrid models, the weight of the vehicles also increases significantly due to the extra weight of the batteries. Since the weight of vehicles has the most significant influence on their consumption and, with it, harmful emissions (even indirectly far from the place of use), manufacturers strive to keep weight under control with continuous improvements. One of the main directions of the developments is the use of new light but at the same time heavy-duty materials with a wide variety of material combinations. These new material pairings pose challenges to knitting technology solutions, which need to be developed similarly. In the course of our research, we are investigating how the surface properties can be optimized in the case of steel with increased strength for the automotive industry, without additional added material and changes visible to the naked eye. We subject the examined DP600 material to a short-pulse laser beam treatment, and we manage to change the surface structure so that the interface properties measured by wetting are significantly improved. The results are confirmed by electron microscopic examinations.

The significance of bonding technology for modern vehicle structural materials is increasingly acknowledged, driven by the adoption of new materials to reduce weight. This is important not only for quality and economic reasons but to address environmental pollution, as well. Traditional joining methods like riveting, screwing, welding, and brazing, are often unsuitable or limited for modern materials. Soldering, an economical and almost waste-free technology, is becoming more widespread. Through optimization, it achieves a strong, durable bond. There is a potential to favourably alter interface properties, including using high energy density surface treatments. Research showed that the laser surface treatment of high-strength steel sheets could improve the mechanical properties of soldered joints.

This paper explores the evolving significance of metal injection molding (MIM) technology, particularly as a promising alternative for the precise and cost-effective manufacturing of small-scale, high-volume products in the automotive industry. Despite its growing adoption, the quality control processes for intermediate “green” parts and the final metal products are not yet well established, posing significant challenges in ensuring product reliability and consistency. Furthermore, the research thoroughly examines the recycling of MIM feedstock and its impact, especially on the change in carbon content. Scanning Electron Microscopy (SEM) images were taken of the samples, the chemical composition was analyzed using Energy-Dispersive X-ray Spectroscopy (EDX), and the pearlitic regions of samples from different generations were compared using image analysis software on microscopic cross-sections.