Processing of HTS Cuprates

Starting assembly Nb filaments in a CuSn (bronze) solid solution matrix, Cu is protected by a barrier Sn core surrounded by Cu embedded in Nb rods, Sn diffusion barrier Nb3Sn embedded in Nb rods bundled in a matrix of pure Cu 

Heat treatment 650-700°C, 50-100h Around 700 °C 700 °C, 2 days, protective atmosphere 

Disadvantage Limited Sn solubility in the bronze, work hardening, repeated annealing after drawing required, Sn gradient in A15 structure Large effective filament size and filament interconnection Nonductflity of the powder core 

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