Structural characterization and microwave properties of chemically functionalized iron particles obtained by high-energy ball milling in paraffin-containing organic environment

Enhanced ballistic and mechanical performance of aluminum nickel phosphorus bronze composites reinforced with TiCN and Y₂O₃ for armored vehicles

In response to emerging military tactics and technological advancements, this research investigates the ballistic and mechanical properties of cutting-edge defense-grade aluminum nickel phosphorus bronze (Al-NPB) metal matrix composites (MMCs), enhanced with 2, 4, and 6 weight percent titanium carbonitride (TiCN) coated yttrium oxide (Y₂O₃). The Y₂O₃ nanoparticles were initially synthesized through mechanical milling, followed by further milling with TiCN to produce TiCN + Y₂O₃ (TY) nanopowders, which were subsequently integrated into the Al-NPB matrix via stir-casting. Comprehensive characterization using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) confirmed the successful formation of the nanocomposite and MMC. Mechanical testing, encompassing tensile, impact, and compression evaluations, revealed that a 4 weight percent filler loading yielded optimal mechanical strength. Additionally, the MMCs were rigorously assessed for corrosion resistance and morphological attributes. Ballistic testing yielded promising outcomes, underscoring the potential applicability of these MMCs in armored fighting vehicles (AFVs). This study introduces a novel MMC that could significantly enhance the performance and durability of AFVs in challenging operational environments, contributing to the advancement of military defense technologies.

High-Magnetization Tetragonal Ferrite-Based Films Induced by Carbon and Oxygen Vacancy Pairs

Herein, a low-temperature thermal decomposition method is utilized to grow new stable tetragonal Fe₃O₄-based thick ferrite films. The tetragonal Fe₃O₄-based film possesses high saturation magnetization of ∼800 emu/cm³. Doping with approximately 10% Co results in a high-energy product of ∼10.9 MGOe with perpendicular magnetocrystalline anisotropy, whereas doping with Ni increases electrical resistivity by a factor of 6 and retains excellent soft magnetic properties (high saturation magnetization and low coercivity). A combined experimental and first-principles study reveals that carbon interstitials (C_i^B) and oxygen vacancies (V_O) form C_i^B-V_O pairs which stabilize the tetragonal phase and enhance saturation magnetization. The magnetization enhancement is further attributed to local ferromagnetic coupling between Fe_A and Fe_B induced by C_i^B-V_O pairs in a tetragonal spinel ferrite lattice.

Imaging the Surface of a Hand-Colored 19th Century Daguerreotype

Daguerreotypes are valued artifacts that constitute a unique historical photographic memory of the 19th century. Understanding their surface chemistry is important in order to conserve and, when necessary, to restore them. Colored highlights were often added by hand to emphasize different features on the daguerreotype's subjects. In the present work, we report on a daguerreotype that was hand-colored with a red pigment that was added to the cheeks of the two individuals. A series of experiments using micro-Raman and micro-Fourier transform infrared spectroscopy and synchrotron-based X-ray fluorescence microscopy and absorption spectroscopy are used to analyze the surface and to determine the nature of the pigment used as well as the common elements present in the fabrication of the daguerreotypes.