Method of producing YBa2 Cu3 O6+x superconductors with high transition temperatures

Claim 1

A method for making an improved ceramic superconductor comprising: (a) mixing an oxide selected from the group consisting of Y 2 O 3 , Er 2 O 3 , Eu 2 O 3 , Yb 2 O 3 , Dy 2 O 3 and Ho 2 O 3 with barium carbonate and copper oxide powders in a ratio of about 50 grams in the case of Y 2 O 3 , 83 grams for Er 2 O 3 , 76 grams for Eu 2 O 3 , 86 grams for Yb 2 O 3 , 80 grams for Dy 2 O 3 , 82 grams of Ho 2 O 3 to about 70 grams of BaCO 3 to about 105 grams of CuO, (b) ball milling the mixture with zironia balls for at least one hour; (c) calcining the mixture at a temperature of 940°C.+or-2° C. with a heating sequence of 2° C. per minute from room temperature to 200° C., (d) maintaining the mixture at the 200° C. temperature for at least about sixty minutes, (e) heating the mixture at 3° C. per minute until a temperature of 940° C.+or -2° C. is reached, (f) maintaining the mixture at the 940° C.+or-2° C. for three hundred minutes, (g) cooling the mixture to room temperature at a rate of 1° C. per minute, (h) adding silver oxide in powdered form to the mixture in an amount of from about 1 to about 20 weight percent, (i) ball milling the mixture containing silver oxide for at least one hour, (j) compacting the mixture, (k) sintering the mixture at 920° C.+or=2° C. by heating the mixture at 2° C. per minute from room temperature to 200° C., maintaining the temperature at 200° C. for 60 minutes and then resuming the heating at 3° C. per minute until a temperature of 920° C. is reached, (l) maintaining the mixture at 920° C.+or-2° C. for three hundred minutes, and (m) cooling the mixture to room temperature at a rate of 1° C. per minute.

Claim 2

A method for making an improved ceramic superconductor comprising: (a) mixing an oxide selected from the group consisting of Y 2 O 3 , Er 2 O 3 , Eu 2 O 3 , Yb 2 O 3 , Dy 2 O 3 and Ho 2 O 3 with barium carbonate and copper oxide powders in a ratio of about 50 grams in the case of Y 2 O 3 , 83 grams for Er 2 O 3 , 76 grams for Eu 2 O 3 , 86 grams for Yb 2 O 3 , 80 grams for Dy 2 O 3 , 82 grams of Ho 2 O 3 to about 70 grams of BaCO 3 to about 105 grams of CuO, (b) ball milling the mixture with zironia balls for at least one hour; (c) calcining the mixture at a temperature of 940°C.+or-2° C. with a heating sequence of 2° C. per minute from room temperature to 200° C., (d) maintaining the mixture at the 200° C. temperature for at least about sixty minutes, (e) heating the mixture at 3° C. per minute until a temperature of 940° C.+or -2° C. is reached, (f) maintaining the mixture at the 940° C.+or-2° C. for three hundred minutes, (g) cooling the mixture to room temperature at a rate of 1° C. per minute, (h) adding silver oxide in powdered form to the mixture in an amount of from about 1 to about 20 weight percent, (i) ball milling the mixture containing silver oxide for at least one hour, (j) compacting the mixture, (k) sintering the mixture at 920° C.+or=2° C. by heating the mixture at 2° C. per minute from room temperature to 200° C., maintaining the temperature at 200° C. for 60 minutes and then resuming the heating at 3° C. per minute until a temperature of 920° C. is reached, (l) maintaining the mixture at 920° C.+or-2° C. for three hundred minutes, and (m) cooling the mixture to room temperature at a rate of 1° C. per minute.