The effect of initial packing density of the OPIT method on the phase formation, electrical transport and mechanical properties of Bi(Pb)SrCaCuO monocore superconducting tapes

Study of BSCCO core density in multicore Ag sheathed tapes by microhardness profiles

“…The maximum, 80%, of theoretical BSCCO density was reached at both powder cores which is in agreement with the highest density presented by Fischer et al [4] and the prediction of Han and Freltoft [8]. Some authors have also shown that a higher initial packing density leads to quicker reaction, converting a greater amount of 2212 phase into 2223 for the same thermomechanical and heat-treatment process [9]. Cold isostatic pressing (CIP) up to 2.5 GPa was used to overcome the limitation of BSCCO core density after drawing and flat rolling [7].…”

Fabrication of (Ba,K)Fe2As2tapes byex situPIT process using Ag-Sn alloy single sheath

“…Table 1 clearly shows that the core hardness before heat treatment directly affects the core hardness after heat treatment, indicating that higher packing density results in higher mass density of the Ba-122 core after sintering. The importance of the initial packing density having a high-quality superconducting core in the PIT process has also been suggested for Ag-sheathed Bi-2223 superconductors [32] and for MgB 2 superconductors using various sheath materials [33]. It is also noticed from table 1 that although the sheaths are softened by recrystallization during the final heat treatment, the Ag-Sn alloy sheath still keeps a much higher level of hardness than the pure Ag sheath.…”

Thermomechanical processing and reaction kinetics of Bi-2223 powder-in-tube tapes made from aerosol precursor

“…The last set of experiments (set C) was based on the findings of the previous two sets of experiments, with the aim of determining the effect of changes in sintering duration following the initial sintering step. These intermediate sintering steps are particularly important because they occur after partial Bi-2223 conversion with accompanying retrograde sintering (first sintering interval) and partial alignment of the Bi-2223 crystallites (first pressing) have commenced, and they have been shown to affect the final J c of fully processed PIT tapes [6][7][8]. In all the above experimental sequences, sintering was carried out at 825 • C Between each sintering step, individual specimens were placed between two steel platens that have been polished with 0.5 µm Al 2 O 3 powder and were uniaxially pressed at 1 GPa.…”

“…These values of critical current density have been found to depend on a large number of processing parameters which were optimized by various investigations [1][2][3][4]. Among these are the precursor powder composition [5], initial tape deformation conditions [6] and core density [7,8], thermomechanical processing parameters [9][10][11] and sample cooling rate [12,13]. In particular, the thermomechanical processing parameters have been shown to affect strongly the extent of Bi-2223 conversion and the degree of grain alignment as well as the final HTS core density of the conductor.…”