Ductile, single phase-continuous super-conducting oxide conductors

A process for preparing a ductile, composite superconductor having a continuous noble metal phase and a continuous superconducting oxide phase comprising the steps of:

• (a) forming a mixture having an overall composition comprising about 1 to 16 atomic percent of a first constituent selected from the group consisting of rare earth metals, about 2 to 25 atomic percent of a second constituent selected from the group consisting of Group II substances, about 3 to 35 atomic percent of copper and about 55 to 95 atomic percent of a fourth constituent selected from the group consisting of noble metals;
• (b) heating said mixture to form a molten alloy;
• (c) rapidly solidifying said molten alloy by expressing said alloy from an orifice so that it immediately impinges onto a chill surface moving at a rate with respect to said expressed molten alloy such that it rapidly solidifies to form an alloy ribbon with a thickness of about 2 to 100 .mu.m;
• (d) heating said alloy ribbon in an inert atmosphere at a pressure of about 10.sup.-5 to 10 atmospheres over a period of about ten minutes to two hours to a first temperature between about 300.degree. C. and 1050.degree. C.;
• (e) introducing at said first temperature an oxygen-containing atmosphere having a total oxygen partial pressure of about 0.1 to 2 atmospheres;
• (f) maintaining said first temperature for a period of about one to fifty hours;
• (g) cooling over a period of about one to five hours to a second temperature between about 500.degree. C. and 700.degree. C.;
• (h) maintaining said second temperature for a period of about five to 50 hours;
• (i) cooling over a period of about one to five hours to a third temperature between about 300.degree. C. and 500.degree. ;
• (j) maintaining said third temperature for a period of about five to 24 hours;
• and
• (k) cooling over a period of about one to five hours to room temperature.

A process for preparing a ductile, continuous, composite superconducting oxide conductor comprising the steps of:

• (a) forming a mixture having an overall composition comprising about 1 to 30 atomic percent of bismuth, about 2 to 35 atomic percent of second constituent selected from the group consisting of Group II substances, about 1.5 to 30 atomic percent of copper and greater than about 60 atomic percent of a fourth constituent selected from the group consisting of noble metals;
• (b) heating said mixture to form a molten alloy, of about 10.sup.3 to 10.sup.7 degrees per second;
• (c) rapidly solidifying said molten alloy;
• at a quench rate
• (d) annealing said solidified alloy in an oxygen containing atmosphere at a temperature and for a period of time sufficient to cause a superconducting oxide phase to migrate to outer surfaces of said composite, thereby forming a superconductor having a continuous noble metal phase and a continuous superconducting oxide phase.

A process for preparing a ductile, composite superconductor having a continuous noble metal phase and a continuous superconducting oxide phase comprising the steps of:

• (a) forming a mixture having an overall composition comprising about 1 to 30 atomic percent of bismuth, about 2 to 35 atomic percent of a second constituent selected from the group consisting of Group II substances, about 1.5 to 30 atomic percent of copper and about 65 to 95 atomic percent of a fourth constituent selected from the group consisting of noble metals;
• (b) heating said mixture to form a molten alloy;
• (c) rapidly solidifying said molten alloy at a quench rate of about 10.sup.3 to 10.sup.7 degrees per second by expressing said alloy from an orifice so that it immediately impinges onto a chill surface moving at a rate with respect to said expressed molten alloy such that it rapidly solidifies to form an alloy ribbon with a thickness of about 2 to 100 .mu.m;
• (d) heating said alloy ribbon in an oxygen containing inert atmosphere having a total oxygen partial pressure of about 0.1 to 2 atmospheres over a period of about ten minutes to two hours to a first temperature between about 300.degree. C. and 1050.degree. C.;
• (e) maintaining said first temperature for a period of about one to six hours;
• and
• (f) cooling over a period of about one to five hours to room temperature thereby causing a superconducting oxide phase to migrate to outer surfaces of said composite and thereby forming a composite superconductor having a continuous noble metal phase and a continuous superconducting oxide phase.