Brass-matrix composites reinforced with 40 and 60 vol.% of Ni₅₉Zr₂₀Ti₁₆Si₂Sn₃ glassy particles were produced by powder metallurgy. The crystallization behavior and the temperature dependence of the viscosity of the glass reinforcement were studied in detail to select the proper sintering parameters in order to avoid crystallization of the glassy phase during consolidation. The brass-glass powder mixtures were prepared through manual blending as well as by ball milling to analyze the effect of the matrix ligament size on the mechanical properties of the composites. The powder mixtures were then consolidated into highly-dense bulk specimens at temperatures within the supercooled liquid region by hot pressing followed by hot extrusion. The preparation of the powder mixtures has a strong influence on the mechanical behavior of the composites. The strength increases from 500 MPa for pure brass to 740 and 925 MPa for the blended composites with 40 and 60vol.% of glass reinforcement, while the strength increases to 1,240 and 1,640 MPa for the corresponding composites produced by ball milling. Modeling of the mechanical properties indicates that this behavior is related to the reduced matrix ligament size characterizing the milled composites.

Electroless Nickel–Phosphorus (Ni-P) coating is recognized mostly for its outstanding corrosion and wear-resistant behavior. The intrinsic corrosion and wear-resistant properties of Ni-P-based coating could be further upgraded by incorporating appropriate second-phase additive particles into the coating matrix. However, such properties of the Ni-P-based coating greatly rely on the surface and microstructural evolution arising with the co-deposition of the additive particles. In this study, submicron Si₃N₄ (average size ~200 nm) and nano Si₃N₄ (average size ~20 nm) particles were incorporated while depositing a Ni-P alloy in a low-carbon steel substrate to develop the Ni-P-Si₃N₄ composites through the electroless coating method. The 20 nm Si₃N₄-incorporated composite coating constituted fewer defects such as cavities and micropores on the surface, but such defects significantly appeared on the surface of the composite after the incorporation of 200 nm Si₃N₄ nanoparticles. Subsequently, the composite Ni-P-Si₃N₄, developed with the co-deposition of 20 nm nanoparticles, is enriched with enhanced anticorrosion characteristics compared with the composite developed with 200 nm nanoparticles. The enhancement of anticorrosion behavior was attributed mainly to the Si₃N₄ nanoparticles that covered the substantial volume of the coating and led to inhibit the formation of corrosion active sites such as defects and metallic Ni phase.

Power generation technologies based on water movement and evaporation use water, which covers more than 70% of the Earth’s surface and can also generate power from moisture in the air. Studies are conducted to diversify materials to increase power generation performance and validate energy generation mechanisms. In this study, a water-based generator was fabricated by coating cellulose acetate with carbon black. To optimize the generator, Fourier-transform infrared spectroscopy, specific surface area, zeta potential, particle size, and electrical performance analyses were conducted. The developed generator is a cylindrical generator with a diameter of 7.5 mm and length of 20 mm, which can generate a voltage of 0.15 V and current of 82 μA. Additionally, we analyzed the power generation performance using three factors (physical properties, cation effect, and evaporation environment) and proposed an energy generation mechanism. Furthermore, we developed an eco-friendly and low-cost generator using natural fibers with a simple manufacturing process. The proposed generator can contribute to the identification of energy generation mechanisms and is expected to be used as an alternative energy source in the future.

Water evaporation-driven energy harvesting is an emerging mechanism for contributing to green energy production with low cost. Herein, we developed polyacrylonitrile (PAN) nanofiber-based evaporation-driven electricity generators (PEEGs) to confirm the feasibility of utilizing electrospun PAN nanofiber mats in an evaporation-driven energy harvesting system. However, PAN nanofiber mats require a support substrate to enhance its durability and stability when it is applied to an evaporation-driven energy generator, which could have additional effects on generation performance. Accordingly, various support substrates, including fiberglass, copper, stainless mesh, and fabric screen, were applied to PEEGs and examined to understand their potential impacts on electrical generation outputs. As a result, the PAN nanofiber mats were successfully converted to a hydrophilic material for an evaporation-driven generator by dip-coating them in nanocarbon black (NCB) solution. Furthermore, specific electrokinetic performance trends were investigated and the peak electricity outputs of V_oc were recorded to be 150.8, 6.5, 2.4, and 215.9 mV, and I_sc outputs were recorded to be 143.8, 60.5, 103.8, and 121.4 μA, from PEEGs with fiberglass, copper, stainless mesh, and fabric screen substrates, respectively. Therefore, the implications of this study would provide further perspectives on the developing evaporation-induced electricity devices based on nanofiber materials.