Internally oxidized Ag/1.2 at.% Mg sheaths for Bi-2223 tapes

Bi-2223 tapes sheathed in dispersion-hardened Ag alloys that contain Mg hav e not generally achieved superconducting properties comparable to those of tapes sheathed in pure Ag. Factors involved in the internal oxidation proce ss, such as oxygen diffusion and evolution of the grain structure of the sh eath, appear to affect phase development of the Bi-2223 superconductor, Ag and Ag/1.2 at.% Mg sheaths, and alloy/Bi-2223 composite tapes, have been pr epared and heat treated. Thermal processing procedures were optimized with respect to the diffusion of oxygen and strength profiles of the sheaths.