Superconductivity already has a variety of practical applications, such as medical imaging and maglev trains. However, in order to apply superconductors to other technologies, we need to not only improve performance, but also reduce the difficulty and cost of manufacturing.
In this regard, magnesium diboride (MgB2), as a superconductor with multiple advantages, has attracted the attention of researchers since its discovery. It is a lightweight, easy to process material that can be made from a wide range of prerequisite materials, which greatly reduces the total cost of using magnesium boride.
A key practical property of a superconductor is its critical current density (Jc). But improving MgB2’s Jc in a more economical way will be difficult.
In a recent paper published in the journal Materials Science and Engineering: B, researchers at Shiura University of Technology (SIT) in Japan developed a technique that utilizes ultrasonic treatment to enhance the Jc of massive MgB2.
This is done by dissolving cheap commercial boron in hexane and using ultrasonic waves to thoroughly disperse the solute. Once vaporized and the hexane is removed, a very fine boron powder is obtained, which is then sintered with magnesium to produce magnesium boride.
The researchers produced high-quality lumps of magnesium boride, most of which contained no oxidizing impurities. Compared to the non-ultrasound treated sample used as a reference, Jc values increased by 20%, depending on the ultrasound treatment time used.
In addition, the results of scanning electron microscopy and energy dispersive X-ray spectroscopy reveal a second mechanism that may lead to enhanced Jc. The team noticed a layered structure covering the boron-deficient pore walls that appeared to be a magnesium boro-oxygen coating.
“This will help reduce the difficulty and cost of superconduct-based technologies and make them more accessible to the general public, especially in the medical field,” the researchers said.
30
3月
