Low-cost and high-strength bi-based superconducting wire/tape and preparation method thereof

A low-cost and high-strength Bi-based superconducting wire/tape prepared by a preparation method of the low-cost and high-strength Bi-based superconducting wire/tape, wherein the low-cost and high strength Bi-based superconducting wire/tape includes at least one of:

• Ag or an Ag alloy as a sheathing material, and a copper layer as a coating, wherein a content of the Ag in the Ag or an Ag alloy as a sheathing material is about 50%, wherein the low-cost and high-strength Bi-based superconducting wire/tape is prepared at least in part by an electrochemical silver reduction process with an ultra-low stress, wherein the low-cost and high-strength Bi-based superconducting wire/tape is fabricated by a method comprising following steps:
• step 1:
• electrochemical silver reduction:
• connecting a first Bi-based superconducting wire/tape to a positive electrode of a stabilized voltage power supply, connecting a graphite electrode to a negative electrode of the stabilized voltage power supply, and arranging the first Bi-based superconducting wire/tape and the graphite electrode in parallel on a bracket;
• and adding an electrolyte to allow the electrochemical silver reduction, such that a Ag alloy layer on a surface of the first Bi-based superconducting wire/tape is removed to obtain a second Bi-based superconducting wire/tape;
• and
• step 2:
• surface enhancement:
• connecting the second Bi-based superconducting wire/tape obtained after the electrochemical silver reduction in the step 1 to the negative electrode of the stabilized voltage power supply, connecting a copper sheet to the positive electrode of the stabilized voltage power supply, and arranging the second Bi-based superconducting wire/tape and the copper sheet in parallel on the bracket;
• and adding an electrochemical additive solution to allow the surface reinforcement, such that a Cu layer is formed on a surface of the second Bi-based superconducting wire/tape to obtain the low-cost and high-strength Bi-based superconducting wire/tape, wherein:
• in the step 2, a distance between the second Bi-based superconducting wire/tape and the copper sheet is 2 cm to 5 cm,
• a current density of the surface of the second Bi-based superconducting wire/tape is 0.1 A/dm2 to 10 A/dm2,
• the surface enhancement is conducted for 0.1 min to 20 min, and
• a thickness of the Cu layer is 10 μm to 40 μm.