Niobium based intermetallics as a source of high-current/high magnetic field superconductors

Abstract

The article is focused on low temperature intermetallic A15 superconducting wires development for nuclear magnetic resonance and nuclear magnetic imaging, MRI, magnets and also for cryogen-free magnets. There are many other applications which would benefit from new development such as future large Hadron collider to be built from A15 intermetallic conductors. This paper highlights the current status of development of the niobium based intermetallics with special attention to Nb 3(Al 1− x ,Ge x ). Discussion is focused on the materials science aspects of conductor manufacture, such as β-phase (A15) formation, with particular emphasis on the maximisation of the superconducting parameters, such as critical current density, J c, critical temperature, T c, and upper critical field, H c2. Many successful manufacturing techniques of the potential niobium–aluminide intermetallic superconducting conductors, such as solid-state processing, liquid–solid processing, rapid heating/cooling processes, are described, compared and assessed. Special emphasis has been laid on conditions under which the J c( B) peak effect occurs in some of the Nb 3(Al,Ge) wires. A novel electrodeoxidizing method developed in Cambridge whereby the alloys and intermetallics are produced cheaply making all superconducting electromagnetic devices, using low cost low temperature superconductors, more cost effective is presented. This new technique has potential to revolutionise the existing superconducting industry enabling reduction of cost orders of magnitude.