Western Metal Materials (China)

High <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn superconducting wires is mainly used in the preparation of high field magnets because of its higher critical current density. Further improving the critical current density of Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn wire, reducing the use amount of wire in magnets is one of important ways to promote the industrialization and mass application of High <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn wire. It is known that doping Ti in Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn phase can improve the critical magnetic field effectively, refine the Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn grains, and improve the critical current density. Too much or too little Ti will greatly reduce the doping effect. The Ti diffusion is later than the Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn phase reaction under three-zone section heat treatment, so the distribution of Ti in Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn phase is uneven. This paper introduces a new heat treatment process, which can improve the uniformity of Ti in Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn phase by adding an insulation platform between the medium temperature and high temperature insulation platform. Eventually, the critical current density of the High <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> Nb<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>Sn wire was improved, reaching 2938 A/mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>.

In recent years, there has been much anticipation for the development of large-capacity rechargeable batteries as a power source for automobiles and other transportation equipment. Our research team is developing battery materials and establishing manufacturing conditions for ribbons using a single-roll rapid solidification method. In this study, we investigated the characteristics of magnesium batteries by evaluating the electrochemical properties of ribbons produced in a previous report and observing their surface structure after charging and discharging. As a result, an increase in overvoltage and current density was observed with increasing roll peripheral speed during CV measurement. This is thought to be due to the increase in cooling rate and the crystal orientation becoming basal-oriented as roll peripheral speed rises. SEM observation of the ribbon surface after electrochemical activation revealed dissolution grooves corresponding to charge-discharge cycles. After discharge, the ribbon surface retained a second phase with a network structure composed of Mg2Ca (C14), Al2Ca (C15) and (Mg, Al) 2Ca (C36), and it was confirmed that α -Mg was preferentially dissolved. Furthermore, after charging, magnesium ions migrated from the positive electrode to the negative electrode, but some did not fully return to the network-like cell interior and instead accumulated on the upper part of the porous layer.

The proliferation of 5G technology has intensified electromagnetic wave (EMW) pollution, promoting the development of MXene absorbers for addressing the above issues. Ti3C2Tx MXene has attracted intensive attention due to its layered structure and superior conductivity. However, one MXene type and its single loss mechanism become frustrated under the increasingly complex electromagnetic environments. Herein, bimetallic solid-solution MXenes, decorated with Fe3O4 nanoparticles via electrostatic self-assembly, were synthesized. The solid solution of Nb/V induces the lattice distortion and alters atomic distribution, generating vacancy defects to serve as polarization centers. Theoretical calculation revealed that the form of electric dipole, resulting from charge density difference, significantly enhances polarization loss. The Fe3O4 incorporation optimizes impedance matching and introduces magnetic loss. Benefiting from synergy loss mechanisms, TiVCTx/Fe3O4 demonstrates the robust electromagnetic wave absorption (EMA) performance at a mass ratio of 1:1, achieving an effective absorption bandwidth (EAB) of 4.56 GHz at a thin thickness of 1.3 mm and the minimum reflection loss (RLmin) achieved at −43.59 dB. Notably, composites show an EAB of 1.36 GHz among low frequencies (3.92–5.28 GHz). This research provides a pathway for exploring bimetallic MXene, revealing its substantial potential for EMA applications in the context of the 5G era.