Method of making continuous length superconducting wires using chemical vapor plating

A method is described for making continuous lengths of superconducting wires using chemical vapor plating techniques and employing a radio-frequency standing wave for heating the substrate. This method was developed for making continuous wires of titanium diboride of high strength and melting point for ablative liners of rocket motors but is adaptable for making wires of niobium-germanium, niobium-gallium, niobium-tin or other similar superconducting materials. A unique feature involves controlled heating of substrate wires of about 0.5 mil diameter of zirconium, niobium, tungsten or other suitable metals by radio-frequency. This is accomplished by using an appropriate antenna arrangement which creates a standing wave to attain wire temperatures in a desired range of 800° to 1300°C. Ordinary resistive heating cannot be used alone but may be used to augment the r.f. heating. Vaporized halide salts containing the substances to be plated are introduced into the plating chamber along with hydrogen and a suitable diluent such as argon. The substrate, drawn continuously through the chamber, and heated to the proper temperature receives the depositing superconducting material which builds up to a controlled diameter of 2 to 5 mils as desired. The continuous wire can be conveniently fabricated into superconducting motors, magnets, cables for power transmission, or other devices.