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Mg alloys are widely used in aerospace and electronics owing to their excellent mechanical and physical properties. However, their utility is hindered by poor tribology and corrosion resistance. This study indicates the efficacy of employing highly hydrophobic "spherical micro-/nanostructures" comprising α-Al2O3/ZrO2 particles, prepared using combustion-synthesis-assisted water atomization and chemical modification methods, along with a one-step spray coating process (epoxy resin (EP)/(α-Al2O3/ZrO2)). This approach notably enhances the corrosion resistance and friction performance of Mg alloys. The study delves into evaluating the tribological properties and corrosion resistance of EP/(α-Al2O3/ZrO2) coatings and Mg alloys with different α-Al2O3/ZrO2 contents under simulated body fluid conditions. At 102 wt % α-Al2O3/ZrO2 content, the nanocomposite coating reaches a surface WCA of 145°, reduces the friction coefficient to 0.087, and exhibits the lowest self-corrosion current alongside the highest self-corrosion potential. The investigation underscores that the combined effect of α-Al2O3/ZrO2 particles in a 102 wt % nanocomposite coating improves the hydrophobicity, friction, and corrosion resistance of Mg alloys, thus broadening their scope of applications. [ABSTRACT FROM AUTHOR]

Low breakdown electric field ZnO–Bi2O3–TiO2–Co2O3–MnO2 (ZBTCM) varistor ceramics doped with various amounts of B2O3 were prepared by the solid-state reactions. The sintering temperature was 900 °C, lower than the melting point of pure silver. The microstructural features and electrical properties were investigated by XRD, SEM and a capacitance meter. The results show that B2O3 is not only a sintering additive, but also an electrical property improver. ZBTCM based varistors with breakdown field of 131.25 V/mm, nonlinear coefficient (α) of 39.13 and leakage current density (JL) lower than 2.5 µA/mm2 were obtained by doping 1 wt% B2O3 sintered at 900 °C. [ABSTRACT FROM AUTHOR]

The nanocomposite multilayer film (NCMF) of substituted BaFe12O19 and TiO2 was prepared using sol-gel method. BaFe10.5Al1.5O19, BaFe10.1Al1.9O19 and BaFe11.4Cr0.6O19 with different absorption frequencies were selected to fabricate the multilayer film with TiO2. The morphology, crystalline structure and microwave absorption property of the NCMF were investigated with an atomic force microscopy, X-ray diffraction and vector network analyses. The results show that the NCMF is uniform without microcracks and it is an ideal microwave attenuation material with a broad frequency range. Its maximum loss efficiency is about −40 dB. The frequency range with the loss above −10 dB is more than 7 GHz. The multilayer film assembles the achievements of each layer film. Moreover, the compounding of ferrites with TiO2 is helpful to absorb more microwave energy. TiO2 particles block the growth of ferrite grains and make most of their size within nanometers. TiO2 also improves the dielectric loss efficiency of the NCMF. [ABSTRACT FROM AUTHOR]

Abstract: The chromium substituted barium hexaferrites were prepared by self-propagating combustion method. The crystalline structure, complex permittivity, complex permeability, and hyperfine parameters of BaFe12−x Cr x O19 (x varies from 0.2 to 1.0 in a step of 0.2) were measured with X-ray diffraction, vector network analyzer and Mössbauer spectroscopy. At 850°C, only a part of Cr3+ ions are permitted to enter the lattice of barium ferrite. With further calcination at 1000°C, all Cr3+ ions enter the lattice. After substitution, the complex permittivity is increased. The Cr3+ ions substitute for the Fe3+ ions on the 2a site, and simultaneously lead to a quadrupole splitting on the 4f 1 site. These changes decrease the anisotropy field, which are accordant with the spectra of μ″. In the crystalline cells of the substituted barium ferrites, some Fe2+ ions are formed. It results in a bigger dielectric loss. [Copyright &y& Elsevier]

Abstract: The composite films of barium ferrite and titanium dioxide are successfully prepared using sol–gel method. The morphology, magnetic and microwave absorption properties of the composite films with the different weight ratio of BaFe12O19 to TiO2 are investigated with atomic force microscopy, vibrating sample magnetometry and vector network analyzer. The results show that the composite films are uniform without microcracks. The grain diameters are less than 100nm. With the increase of barium ferrite, the grain diameter decreases. The composite films possess the excellent magnetic and microwave absorption properties. The specific saturation magnetization and coercivity is 18.3EMU/g and 3350Oe, respectively. The maximum microwave loss reaches 40dB when the weight ratio of BaFe12O19 to TiO2 is 3:5. [Copyright &y& Elsevier]

Abstract: The composite films with different weight ratio of barium ferrite to titanium dioxide are successfully prepared using sol–gel method for the first time. The morphology, crystal structure and magnetic properties of composite films are investigated with atomic force microscopy, X-ray diffraction and vibrating sample magnetometry. The results show that the composite films are uniform with no microcracks. The grain diameters are less than 100nm. With the increase of barium ferrite, the grain diameter decreases. The composite films are composed of M-type hexagonal barium ferrite and rutile titanium dioxide. The composite films possess the excellent magnetic properties. The specific saturation magnetization and coercivity reach 18.3emu/g and 3350Oe, respectively. The application of composite films in magnetic recording and electromagnetic absorption fields is promising. [Copyright &y& Elsevier]