| 摘要 |
PROBLEM TO BE SOLVED: To increase a critical current density by filling a powdery mixture of specified fine powder Tl2 O3 , PbO and Bi2 O3 , into a sliver tube, drawing and rolling the tube and heat-treating a resultant tape. SOLUTION: Fine powder represented by formula I is formed by mixing SrO or SrCO3 with BaO or BaCO3 , CaO or CaCO3 and CuO so that the cation ratio of Sr:Ba:Ca:Cu is regulated to (1.6±0.05):(0.4±0.05):(2.1±0.05):(3.0±0.1), pulverizing the resultant mixture and carrying out heat treatment at 900-920 deg.C for <=50hr. The fine powder is mixed with Tl2 O3 , PbO and Bi2 O3 so that the cation ratio of Tl:Pb:Bi:Sr:Ba:Ca:Cu is reflected to (0.7±0.1):(0.2±0.1):(0.2±0.1):(1.6±0.05):(0.4±0.05):(2.1±0.1):(3.0±0.1), the resultant mixture is filled into a silver tube and this tube is drawn and rolled to form a tape. This tape is heat-treated at 800-850 deg.C for <=1hr and further heat-treated at 810-850 deg.C for <=10hr to obtain the objective high temp. superconducting clad wire represented by formula II.
|
