Title :
Ag-2223 (Bi) tapes structure and superconducting properties in dependence of initial powder type
Author :
Nikulin, A.D. ; Shikov, A.K. ; Khlebova, N.E. ; Antipova, E.V. ; Dontsova, E.S. ; Akimov, I.I. ; Kazakov, E.Y. ; Vargin, V.A. ; Medvedev, M.I. ; Kozlenkova, N.I. ; Klepatsky, V.E.
Author_Institution :
A.A. Bochvar All-Union Sci. Res. Inst. of Inorg. Mater., Moscow, Russia
fDate :
7/1/1994 12:00:00 AM
Abstract :
An investigation was carried out into the critical properties and specific features of structure in composite tapes with a core material of composition 2:2:2:3,2 in a bismuth system produced by the freeze drying technique and taken at different stages of the synthesis process. Consideration is given to powder behaviour in the process of cold drawing and rolling of composite tapes followed by heat treatment under similar conditions as well as to evolution of microstructure, specifically of texture and kinetics of superconducting phase formation. It is shown that the most favourable type of structure in heat treated superconductors develops when core material powder is used in the form of a precursor consisting of fine mixture of dioxides and “2212” phase resultant from calcination within the interval 750-800°C. A critical current density of more than 104 A/cm2 at 77 K was achieved in the composite tapes. The results of testing for small coils are presented
Keywords :
bismuth compounds; calcium compounds; cold rolling; composite superconductors; critical current density (superconductivity); heat treatment; high-temperature superconductors; lead compounds; powder technology; silver; strontium compounds; superconducting magnets; 2212 phase; 750 to 800 C; Ag-2223 tapes; Bi1.6Pb0.4Sr2Ca2Cu 3.2O-Ag; calcination; cold drawing; cold rolling; composite tapes; critical current density; freeze drying; heat treatment; microstructure evolution; powder behaviour; small coils; superconducting phase formation; superconducting properties; texture; Bismuth; Calcination; Composite materials; Heat treatment; Kinetic theory; Microstructure; Powders; Superconducting films; Superconducting materials; Superconductivity;
Journal_Title :
Magnetics, IEEE Transactions on
