Degradation of YBC critical current as a result of annealing in air

The present study was aimed at determining the rate of degradation of the transport critical current density Jc of ceramic YBCO stored in atmosphere, as a function of temperature. The transport critical current of ring-shaped samples was measured by the inductance technique. The samples were prepared by the standard method. The results show that annealing at 100 °C for over 500 h caused practically no degradation of Jc. Above 100 °C the rate of degradation increases rapidly with temperature.