Bi 系高温超导带材冷压工艺优化的试验研究

INVESTIGATIONS ON THE OPTIMIZATION OF COLD PRESSING OF Ag CLAD Bi 2223 SUPERCONDUCTING TAPES

采用套管法（ＰＩＴ）制备Ｂｉ系高温超导带材，进行了冷压工艺的优化研究。试验结果表明，Ｂｉ系带材所能承受的压力有一个限值，若超过这个限值后，密度虽可提高，但晶粒破碎严重，ＪＣ值反而降低。带材优化的冷压工艺参数是８３８℃／６０ｈ＋冷压＋８３８℃／６０ｈ＋冷压＋８３８℃／６０ｈ；第一次压力为２ＧＰａ，第二次为２．５ＧＰａ；冷压压下速率为１．７５×１０－４ｍｍ／ｓ。同时研究还表明，冷压的主要作用是提高带材的致密度和晶粒取向度，从而最终改善带材的超导性能。

Optimum procedures of cold pressing of Bi 2223 Ag clad superconducting tapes fabricated by Powder in tube method were investigated.Cold pressing was necessary to produce tapes with good texture and high J C values.The optimum technical parameters are sintering three times at 838℃ for 60h and pressing twice with pressure 2.0GPa and 2.5GPa for the first and second compaction respectively.Reduction rate of cold pressing was 1.75×10 -4 mm/s.Meanwhile,experimental results exhibited that high density and degree of grain alignment of the tapes were mainly attributed to cold pressing.