Effect of lead content on the formation of the 2223 phase

摘要

Freeze-dried powders have been used for the formation of the high Tc (110 K) superconducting phase in the Bi-Sr-Ca-Cu-O system. Effects of lead content and oxygen partial pressure were investigated. It was shown that lead content and oxygen partial pressure were affecting liquid phase formation. Lead content affected the dissolution of the 2212 phase into the liquid phase from which the 2223 high Tc superconducting phase forms. Powder reacted as pellet with Bi(sub 1.8)Pb(sub 0.4)Sr(sub 2.0)Ca(sub 2.0)Cu(sub 3.0)O(sub x) composition shows essentially phase pure 2223 after 12 hrs at 845(degrees) C in 7%O(sub 2).