With the increasing demand for electronic products, the amount of multilayer ceramic capacitor (MLCC) waste has also increased. Recycling technology has recently gained attention because it can simultaneously address raw material supply and waste disposal issues. However, research on recovering valuable metals from MLCCs and converting the recovered metals into high-value-added materials remains insufficient. Herein, we describe an electrospinning (E-spinning) process to recover nickel from MLCCs and modulate the morphology of the recovered nickel oxide particles. The nickel oxalate powder was recovered using organic acid leaching and precipitation. Nickel oxide nanoparticles were prepared via heat treatment and ultrasonic milling. A mixture of nickel oxide particles and polyvinylpyrrolidone (PVP) was used as the E-spinning solution. A PVP/NiO nanowire composite was fabricated via Espinning, and a nickel oxide nanowire with a network structure was manufactured through calcination. The nanowire diameters and morphologies are discussed based on the nickel oxide content in the E-spinning solution.

One-dimensional rutile TiO₂ is an important inorganic compound with applicability in sensors, solar cells, and Li-based batteries. However, conventional synthesis methods for TiO₂ nanowires are complicated and entail risks of environmental contamination. In this work, we report the growth of TiO₂ nanowires on a Ti alloy powder (Ti-6wt%Al-4wt%V, Ti64) using simple thermal oxidation under a limited supply of O₂. The optimum condition for TiO₂ nanowire synthesis is studied for variables including temperature, time, and pressure. TiO₂ nanowires of ~5 μm in length and 100 nm in thickness are richly synthesized under the optimum condition with single-crystalline rutile phases. The formation of TiO₂ nanowires is greatly influenced by synthesis temperature and pressure. The synthesized TiO₂ nanowires are characterized using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HR-TEM).

Vertically oriented nickel nanowire arrays with a different diameter and length are synthesized in porous anodic aluminium oxide templates by an electrodeposition method. The pore diameters of the templates are adjusted by controlling the anodization conditions and then they are utilized as templates to grow nickel nanowire arrays. The nickel nanowires have the average diameters of approximately 25 and 260 nm and the crystal structure, morphology and microstructure of the nanowires are systematically investigated using XRD, FE-SEM and TEM analysis. The nickel nanowire arrays show a magnetic anisotropy with the easy axis parallel to the nanowires and the coercivity and remanence enhance with decreasing a wire diameter and increasing a wire length.