DEVELOPMENTS IN LOW TEMPERATURE SUPERCONDUCTOR MATERIALS AT CABOT PERFORMANCE MATERIALS

摘要

Cabot Performance Materials (CPM) is a producer of niobium, tantalum and their alloys which are commonly used in low temperature superconductor (LTS) applications. Fabrication processes for LTS applications generally require very high area reduction sequences which in turn require quality levels exceeding detection limits of conventional non-destructive testing techniques. CPM has developed a range of LTS materials which have or produce the desired superconducting characteristics and incorporate the required quality levels. This range includes barrier grade niobium and RRR>300 niobium for RF Cavity Accelerators to materials for A-15 composite fabrication (niobium alloy rod and tantalum barrier sheet and tube) to NbTi rod and billet for Magnetic Resonance Imaging and High Energy Physics applications. This report describes the application of nondestructive testing as part of the production processes which ensure the quality levels needed for the high reduction ratios employed in the fabrication processes. Certain types of manufacturing non-uniformity's can sustain these high mechanical deformation ratios with no negative impact on processing or properties and can be managed in the production process through non-destructive techniques. Interaction with customers has allowed refinement of manufacturing processes and inspection techniques as well as material compositions and specifications to improve the overall performance of niobium based LTS materials.