Influence of Reaction Kinetics on MgB2 Wires with Enhanced Properties: Optimization of Copper-Coated Magnesium Rod and Carbon-Coated Nano-Boron Powders in IMD Process
Magnesium diboride (MgB₂) wires fabricated by Internal Magnesium Diffusion (IMD) process are of renewed recent interest for potential superconducting applications due to their improved superconducting properties with flux pinning, high critical temperature (Tc ≈ 39 K), cost-effectiveness, and potential for large-scale production. This talk focuses on the impacts of varying copper coatings on magnesium rods and the incorporation of different carbon-coated boron powders with experimental works on the microstructural and superconducting properties of MgB₂ wires. By systematically varying the copper coating content on Mg rods at various percentages and the carbon coated boron powder precursors, we aim to optimize the enhanced critical current density (Jc) especially in the applied magnetic fields. Characterization techniques such as optical microscopy, scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS), DTA analysis for reaction kinetics and electrical transport measurements were carried out to investigate the effects of porosity, grain connectivity, morphology, and superconducting physical properties of the MgB₂ wires.
The results show that both carbon and copper doping play an important role in enhancing flux pinning by introducing nanoscale defects and impurities that act as pinning centers for the vortices. However, excessive doping or improper copper coating thickness can lead to the formation of unwanted secondary phases and defects, which may a negative effect the superconducting properties and mechanical stability.
In conclusion, this study provides valuable insights into optimizing the IMD process for the fabrication of high performance MgB₂ wires. By balancing the thickness of the copper coating and the concentration of carbon doping, improved superconducting properties can be achieved, making the processed MgB₂ wires highly suitable for applications such as magnetic resonance imaging (MRI), particle accelerators, and high-field magnets. Experimental results with model dependent analysis will be presented to achieve higher critical current density at fields exceeding from 1 to 12 T.
This work has been supported by TÜBİTAK and Chinese Academy of Sciences (CAS) via Bilateral Cooperation under contract No: 123N624