From Hot to Cold: Advanced Materials and Processes for NbSn Based Magnets<sub/>
André Brem, M. Duda, Colin Müller, Henrique Garcia, Christoph Hug, Michael Daly, Douglas Martins Araujo, Jaap Kosse, S. Otten, A. Kario, Herman H.J. ten Kate, Attilio Milanese, Bernhard Auchmann
Abstract
We worked out an approach for obtaining “clean” magnets by introducing oxygen during the reaction heat treatment (RHT) of a single glass fiber insulated Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn Rutherford cable in a channel. A reduction of the RRR by 16% was measured while the glass fiber insulation and support structure was visually clean after the RHT. We developed a filled wax system, consisting of fully refined paraffin wax, carnauba wax and alumina particles, which is compatible with the common glass fiber insulation on Rutherford cables. The filled wax showed a flexural modulus of 19 GPa at -100°C and a thermal shrinkage of -1.2 % from RT to 77 K. We used a commercial glass ceramic coating on stainless steel as primary insulation in single cable in a channel applications or as secondary electrical insulation from the former. The coating survives the RHT and operation temperatures and keeps its electrical insulation properties.