B. Wolf et al., MASS DENSITY EVOLUTION DURING MANUFACTURING OF AG-SHEATHED BPSCCO TAPES, Superconductor science and technology, 9(7), 1996, pp. 589-597
The mass density of superconducting (bismuth, lead)-strontium-calcium-
copper-oxide (PBSCCO) cores of silver-sheathed tapes, subject to diffe
rent states of cold working and thermal treatment, has been determined
taking advantage of a modified hydrostatic weighing. It turned out th
at the densification was more effective the smaller the initial densit
y of the parent material. A core density of about 5 g cm(-3) was attai
ned, but could not be exceeded, independent of the deformation method
and core density prior to deformation. When starting with high initial
densities, drawing even reduced the core density. The density drop in
creased with reduced diameter reduction per drawing step, whereas roll
ing improved the core density. Heat treatment (reacting from the 2212
to the 2223 phase) resulted in a small loss of relative density, which
raised with increasing core thickness. Nevertheless there is a positi
ve correlation between densities before and after heat treatment. It i
s therefore important to obtain optimum core densities during the fina
l steps of cold working.