Producing powder-in-tube-high-temperature superconductor-wire with noble metal sheath made of silver/silver alloy, by coating semi-finished product of wire with separating agent, and applying aqueous suspension of agent on product surface

摘要

The method for producing powder-in-tube(PIT)-high-temperature superconductor (HTSL)-wires (7) with a noble metal sheath made of silver or silver alloy, comprises coating a semi-finished product (1) of the HTSL-wires with a separating agent, applying an aqueous suspension (3) of the separating agent on a surface of the semi-finished product, subjecting the coated semi-finished product to a heat treatment, reacting a precursor of HTSL-material in the semi-finished product for HTSL-material of the HTSL-wires, and removing the separating agent from the surface of the reacted HTSL-wires. The method for producing powder-in-tube(PIT)-high-temperature superconductor (HTSL)-wires (7) with a noble metal sheath made of silver or silver alloy, comprises coating a semi-finished product (1) of the HTSL-wires with a separating agent, applying an aqueous suspension (3) of the separating agent on a surface of the semi-finished product, subjecting the coated semi-finished product to a heat treatment, reacting a precursor of HTSL-material in the semi-finished product for HTSL-material of the HTSL-wires, and removing the separating agent from the surface of the reacted HTSL-wires, where zinc oxide is used as separating agent. The value (D50) of grain size distribution of the separating agent in the aqueous suspension is = 2 mu m. The aqueous suspension contains 5% of mass portion of the separating agent, and is a surfactant and a mixture of surfactants. The aqueous suspension is dripped or sprayed onto the semi-finished product and then the semi-finished product is hot-dried. The semi-finished product contains a precursor of bismuth-2223 or bismuth-2212. The heat treatment takes place at 700[deg] C or more. The surface of the HTSL-wires is exposed to a weak acidic aqueous solution (9) with a pH of 2-3, and is flushed off with flowing weak acidic aqueous solution. The HTSL-wire is pulled through a basin filled with weak acidic aqueous solution. The surface of the HTSL-wires is treated with a brush-like stripper. After the treatment of the HTSL-wires with the weak acidic aqueous solution, the surface of the HTSL-wires is cleaned with deionized water.