2015

Dense MgB₂ superconducting layer made by diffusion process (IMD)

SEM image of IMD MgB₂ single wire torn after cooling down by liquid nitrogen (a) and TEM BF image of MgB₂layer (b).

Microstructure of dense pore-free MgB₂ layers in single filament wires made by internal magnesium diffusion process (IMD) have been analysed. The superconducting layer consists of nearly pure MgB₂ phase with small volume fraction of nano-sized Mg and MgO precipitates and some of amorphous or nano-crystalline B-rich grains. Content of oxygen in IMD wires was significantly suppressed in comparison to PIT technology. Thin Mg layers were observed on plate-shaped MgB₂ grain boundaries. Electrical measurements have shown high critical current densities in MgB₂ layer, which are promising for further improvements and also for possible applications.

Rosová, A., Hušek, I., Kováč, P., Dobročka, E., and Melišek, T.: Microstructure of MgB₂ superconducting wire prepared by internal magnesium diffusion process, J. Alloys Comp. 619 (2015) 726-732.

Kováč, P., Hušek, I., Rosová, A., Kulich, M., Melišek, T., Kopera, Ľ., and Brunner, B.: Properties of MgB₂ wires made by internal magnesium diffusion into different boron powders, Supercond. Sci Technol. 28 (2015) 095014.

Brunner, B., Windbichler, A., Reissner, M., Kováč, P., and Hušek, I.: Comparison of critical current density and pinning behaviour of mono-core MgB₂ wires prepared by different method, J. Supercond. Novel Magn. 28 (2015) 443-446.