Liquid-Phase Shock-Assisted Consolidation of Superconducting MgB2 Composites

Abstract

An original two-stage liquid-phase hot explosive compaction (HEC) procedure of Mg-B precursors above 900 • C provides the formation of superconductivity MgB 2 phase in the whole volume of billets with maximal T c = 38.5 K without any further sintering. The liquid-phase HEC strongly increases the solid-state reaction rate similar to photostimulation, but in this case, due to the high penetrating capability of shock waves in a whole volume of cylindrical billets and consolidation of MgB 2 precursors near to theoretical density allows one to produce bulk, longbody cylindrical samples important for a number practical applications.

Using Fast Hot Shock Wave Consolidation Technology to Produce Superconducting MgB2

“…In order to evaluate the superconductive characteristics of obtained billets the magnetic moment temperature dependence in zero-field-cooled (ZFC) and field-cooled (FC) modes depending on experimental conditions and type of boron precursors were investigated. As reported in [9,12] the application of low temperatures up to 900 0 C and HEC of Mg-2B precursors in steel containers did not give results. In spite of high density and uniform distribution of phases they did not obtain superconductive characteristics.…”

“…The novelty of the proposed nonconventional approach relies on the fact that the consolidation of the samples from coarse (under 10-15 µ) Mg-2B blend powders was performed in two stages [9]. The explosive pre-densification of the powders was made at room temperatures.…”

“…The heating billet is fixed in the furnace by an opening and closing mechanism (6). After reaching the necessary temperature the opening (6) sheet opens the furnace and the billet moves through the feeding system (9)(10)(11) to the explosive charge set-up (17). After receiving the signal that the billet passed through the feeding system and is located in final position (13), the detonation takes place and explosive compression of heated billets occurs.…”

On the Nature of Superconducting Precursors in Bi-Pb-Sr-Ca-Cu-O Compositions Fabricated by Hot Shock Wave Consolidation Technology

“…The application of shock wave pressure proved to be an effective method to generate such superconducting interfaces [6]. The HSWC technology was recently successfully applied for the fast production of superconducting MgB 2 samples avoiding long-time solid state reaction procedures [7]. We present further the experimental results of study of the HTSC samples of Bi-Pb-Sr-Ca-Cu-O system fabricated by the HSWC technology showing the possibility to increase significantly their critical temperature Т c .…”