Dynamic fatigue behaviour of Ag-doped Bi-2212 textured thin rods

The flexural strength of 1 wt.% Ag-doped Bi₂Sr₂CaCu₂O_8+δ thin rods textured by a laser heated floating zone was measured as a function of the environmental conditions (air versus water) at room temperature. Loading rates spanning three orders of magnitude (1, 10 and 100 μm/min) were used to explore their susceptibility to the environmental conditions. These mechanical tests were completed with electrical characterization (critical current at 77K and resistivity from 77 to 300 K) of samples submerged in distilled water for different time lengths (0, 12 and 120h). While Bi₂Sr₂CaCu₂O_8+δ has been shown, in previous works, to be unstable during contact with water molecules, the Ag-doped Bi-2212 textured rods tested in this work are very inert to the water environment, with respect to their mechanical and electrical properties, due to the presence of a narrow (≈150 μm) low textured outer ring formed in the growth process.