Preparation of A15 Nb3Ge tape by a single-roller rapid quenching technique

We have Prepared a high Tc Nb3Ge tape by using a single-roller rapid quenching apparatus specially made for high melting point alloy applications. The rapid quenching of Nb3Ge produced amorphous ribbons for compositions at Ge = 21 ∼ 27at %. Heat-treatment at 700° c for 100 hours converted these amorphous ribbons into nearly single phase A15 (Ge = 21 ∼ 24at.%) and A15+Nb5Ge3(Ge = 25 ∼ 27at.%). The superconducting transition temperature Tc was about 4K for the amorphous phase, While the heat-treatment improved Tc values considerably; the highest Tc value, 18.3K(onset) with ΔTc=0.6K, was obtained from Ge=23at.%.