Method for the preparation of highly densified superconductor massive bodies of MgB2, relevant solid end-products and their use

A method for the preparation of superconducting massive bodies of MgB2, having a density close to the theoretical value, which comprises the following steps:

• a) mechanically activating crystalline boron to form activated powders;
• b) forming a porous preform of activated crystalline boron powders;
• c) assembling the porous boron preform and massive precursors of metallic magnesium in a container and sealing said container in an atmosphere of inert gas or an atmosphere with a low oxygen content, wherein said sealed container is capable of counterbalancing the internal pressure in said container which is generated during thermal treatment and is also capable of preventing the contents of said container from contamination with atmospheric oxygen during thermal treatment;
• d) thermally treating the boron and magnesium as assembled above, at a temperature higher than 700° C. for a time greater than 30 minutes, with the consequent percolation of the magnesium, in liquid phase, through the activated crystalline boron powders.