Coffey et al. [1] reported the operation of a 100-kG superconducting solenoid using Nb-Zr and Nb-Ti superconducting wire. The Nb-Zr was used in the outer section of the coil, while Nb-Ti wire was used in the inside section. Since then, some of the attempts to use Nb-Ti wire have not been successful, The reason became apparent when it was discovered that Nb-Ti wire was supplied in a heat-treated condition with a thin copper coating. As with Nh-Zr, a heat treatment of the materials will increase the current carrying capacity, but at the same time will lead to instabilities which make them unsuitable for particular applications unless they are fully stabilized [2]. This paper reports on the stabilization of Nb-Ti superconducting wire, its heat treatment and its use in an operating coil.

The importance of Nb—Ti alloys in superconducting technology has made it necessary to determine the complete superconducting properties of these alloys.

The basic requirements for MHD generator coils are set forth, and performance of a typical MHD generator with room temperature, cryogenically cooled, or superconducting coils is analyzed. Various geometric configurations are considered for productng high magnetic fields parallel and perpendicular to the axis of a cylindrical volume. These configurations are compared on the basis of maximum field per unit power expenditure, maximum field per unit mass of conductor, and uniformity of field in the region of interest. Comparison is made between water cooled, cryogenically cooled, and superconducting coils. Their respective areas of application are defined and the problems associated with each are discussed. (auth)