Oxide superconductor thick film and method for manufacturing the same

Abstract

The present invention provides an oxide superconductor thick film which is formed on a substrate or a board and has a high Jc and Ic and a method for manufacturing the same. Predetermined amounts of materials containing elements of Bi, Pb, Sr, Ca and Cu are weighed, mixed and subjected to steps of calcining, milling, and drying, and thereafter an organic binder and an organic vehicle are added thereto to prepare a (Bi, Pb) 2+a Sr 2 Ca 2 Cu 3 O z superconductive paste, which is applied to the surface of a substrate or a board in a thickness of 260 μm or more and dried. Thereafter, the paste is first subjected to burning at temperatures of 835° C. to 840° C. for 100 hours, then pressurization, and further burning at temperatures of 835° C. to 840° C. for 100 hours, thereby preparing an oxide superconductor thick film having a film thickness of 130 μm or more having a high Jc and Ic.

1 . An oxide superconductor burned thick film containing Bi, Pb, Sr, Ca and Cu capable of being formed on a surface of a substrate or a board, wherein of the thick film has a film thickness of 130 μm or more.  
     
     
         2 . An oxide superconductor structure, comprising the oxide superconductor burned thick film of  claim 1  formed on a surface of a substrate or a board.  
     
     
         3 . An oxide superconductor burned thick film containing Bi, Pb, Sr, Ca and Cu capable of being formed on a surface of a substrate or a board, wherein: 
 the thick film has a film thickness of 130 μm or more; and    the thick film has a critical current density (Jc) of 3800 A/cm 2  or more.    
     
     
         4 . An oxide superconductor structure, comprising the oxide superconductor burned thick film of  claim 3  formed on a surface of a substrate or a board.  
     
     
         5 . An oxide superconductor burned thick film containing Bi, Pb, Sr, Ca and Cu capable of being formed on a surface of a substrate or a board, wherein: 
 the thick film has a signal strength of Pb at a postion directly on the surface of the substrate or board measured by an EPMA of 0.67 or more relative to a signal strength of Pb in a center part of a bulk body measured by the EPMA normalized as 1; and    the bulk body is formed when an oxide superconductive synthetic powder having a mole ratio of Bi:Pb:Sr:Ca:Cu=1.85:0.35:1.90:2.05:3.05 is burned at 850° C. for 100 hours and then compressed with a pressure of 3 ton/cm 2  using a CIP, and further burned at 850° C. for 100 hours to prepare a bulk body of an oxide superconductor containing (Bi, Pb) 2+a Sr 2 Ca 2 Cu 3 O z  (0<a<0.5).    
     
     
         6 . An oxide superconductor structure, comprising the oxide superconductor burned thick film of  claim 5  formed on a surface of a substrate or a board.  
     
     
         7 . An oxide superconductor burned thick film containing Bi, Pb, Sr, Ca and Cu capable of being formed on a surface of a substrate or a board, wherein 
 the thick film has a signal strength of Pb at a postion directly on the surface of the substrate or board measured by an EPMA of 0.67 or more relative to a signal strength of Pb in a center part of a bulk body measured by the EPMA normalized as 1;    the bulk body is formed when an oxide superconductive synthetic powder having a mole ratio of Bi:Pb:Sr:Ca:Cu=1.85:0.35:1.90:2.05:3.05 is burned at 850° C. for 100 hours and then compressed with a pressure of 3 ton/cm 2  using a CIP, and further burned at 850° C. for 100 hours to prepare a bulk body of an oxide superconductor containing (Bi, Pb) 2+a Sr 2 Ca 2 Cu 3 O z  (0<a<0.5); and    the thick film has a critical current density (Jc) of 3800 A/cm or more.    
     
     
         8 . An oxide superconductor structure, comprising the oxide superconductor burned thick film of  claim 7  formed on a surface of a substrate or a board.  
     
     
         9 . An oxide superconductor burned thick film containing Bi, Pb, Sr, Ca and Cu capable of being formed on a surface of a substrate or a board, wherein 
 the thick film has a film thickness of 130 μm or more; and    the thick film has a signal strength of Pb at a postion directly on the surface of the substrate or board measured by an EPMA of 0.67 or more relative to a signal strength of Pb in a center part of a bulk body measured by the EPMA normalized as 1; and    the bulk body is formed when an oxide superconductive synthetic powder having a mole ratio of Bi:Pb:Sr:Ca:Cu=1.85:0.35:1.90:2.05:3.05 is burned at 850° C. for 100 hours and then compressed with a pressure of 3 ton/cm 2  using a CIP, and further burned at 850° C. for 100 hours to prepare a bulk body of an oxide superconductor containing (Bi, Pb) 2+a Sr 2 Ca 2 Cu 3 O z  (0<a<0.5).    
     
     
         10 . An oxide superconductor structure, comprising the oxide superconductor burned thick film of  claim 9  formed on a surface of a substrate or a board.  
     
     
         11 . An oxide superconductor burned thick film containing Bi, Pb, Sr, Ca and Cu capable of being formed on a surface of a substrate or a board, wherein 
 the thick film has a film thickness of 130 μm or more;    the thick film has a signal strength of Pb at a postion directly on the surface of the substrate or board measured by an EPMA of 0.67 or more relative to a signal strength of Pb in a center part of a bulk body measured by the EPMA normalized as 1;    the bulk body is formed when an oxide superconductive synthetic powder having a mole ratio of Bi:Pb:Sr:Ca:Cu=1.85:0.35:1.90:2.05:3.05 is burned at 850° C. for 100 hours and then compressed with a pressure of 3 ton/cm 2  using a CIP, and further burned at 850° C. for 100 hours to prepare a bulk body of an oxide superconductor containing (Bi, Pb) 2+a Sr 2 Ca 2 Cu 3 O z  (0<a<0.5); and    the thick film has a critical current density (Jc) of 3800 A/cm 2  or more.    
     
     
         12 . An oxide superconductor structure, comprising the oxide superconductor burned thick film of  claim 11  formed on a surface of a substrate or a board.  
     
     
         13 - 14 . (canceled)