Apparatus and method for preparing superconducting joints

An apparatus for forming a superconductive joint in tape or wire includes a closeable vessel with means eg 9 for introducing gases for depositing a superconducting layer by chemical vapor deposition, and forming means 11 in combination with securing and current passage means 29 to heat a length of tape to a temperature effective to deposit a superconductive coating thereon. Preferably, the forming means and associated structure are unitary with a base plate ion 2 which seals the vessel. The method includes stripping non- superconductive material from the tape ends, joining them with a conductive coating and depositing a superconductive alloy layer thereon, typically of triniobium tin, by a chemical vapor deposition reaction of hydrogen with the corresponding metal halides. Certain of the steps are performed in an inert atmosphere free from moisture, elemental hydrogen and elemental oxygen, typically a helium atmosphere. The step of depositing a superconducting alloy is performed in the above apparatus.