Speaker
Description
The aim to improve critical properties of MgB2 is crucial for its future application. Introduction of artificial pinning center (APC) in MgB2 will be a key factor for enhancement of critical current density. Here we report the progress on synthesis of boron precursor prepared following a patented process developed at SPIN-CNR laboratories. Basic idea is manipulate B precursor B2O3 in liquid phase (water solution) where it is possible to introduce homogeneous dopants by dispersion. Solution is sprayed in liquid nitrogen and freeze-dried to remove water and keep homogeneous dopant distribution.
Dopants must be soluble in water and resist to hydrolysis up to about 80-100 °C, with a large pool of possible candidates. We report a systematic study on the effect of poly-saccharide at different concentrations on MgB2 and interaction of C-rich aggregates with surrounding lattice. BN, CaF2, ZrO2 and TiO2 were used as dopants by preparing a stable suspension of these ceramic materials and their effects on critical properties and morphology are reported. Chlorides of transition metals (Zr, Ti, Y) were investigated for the possibility to introduce nanometrical binary borides coherently with MgB2 lattice, useful as effective pinning centres.
