Melting of Ag–Y Ba2Cu3O7 interfaces: the path to large area high critical current welds

The interface melting process of melt-textured Y Ba2Cu3O7 induced by Ag foils has been investigated in view of developing a large area welding technology. The influence of the processing methodology and the initial microstructure of the melt-textured ceramics has been considered. High temperature quench experiments have shown that the interface molten region can become inhomogeneous due to microstructural features of the initial ceramics such as the pre-existing cracks. It is found that while thick Ag foils () can lead to severe liquid Ag migration, the artificial welds performed with thinner foils () in non-oxygenated melt textured Y Ba2Cu3O7 samples free of cracks are of high quality in large areas. High critical currents through welded interfaces have been demonstrated by means of Hall probe magnetic imaging and Biot–Savart inversion calculations.