Recrystallization and densification of Bi 2212 glass ceramics
Abstract
Ceramic superconductors are promising materials suitable for industrial applications because of their high critical temperatures, Tc. However, two fundamental problems on these materials dominating their current-carrying capacity are (1) brittleness and porosity, and (2) "weak links" and "weak pinning." In order to fabricate a high-temperature superconductor (HTSC) material suitable for practical use such as a superconducting magnet, it is necessary to develop an appropriately shaped material with a high critical current density, Jc.
This study utilizes the Glass-ceramic process to fabricate Bi 2212 superconductors. This technique is envisioned to be an effective process for densification, crystal alignment, and introducing pinning centers in the polycrystallinc HTSC. Lee et al. found that using the melting-quenching-reheating process, the Tc and Jc of the resultant ceramics obtained via heat treatment of devitrified precursors are much higher than those of the glassy phase.
The objectives of this research are twofold: (1) to synthesize glass ceramic Bi 2212 superconductors via the glass ceramic melt-quenching technique, and (2) to determine the sintering time dependence of material properties such as crystallinity, density and microstructural characteristics.