Degradation of High-Temperature Superconductor YBa2Cu3O7-x in Water

The degradation of YBa 1 Cu 3 O 7- x (YBCO) sintered disks was examined by soaking the disks in water at 25°C. By magnetic susceptibility measurements, the degree of the degradation was found to depend on the pressure aplied when forming the disk from YBCO powders. From the analysis of our results, we derived an optimum pressure of 16.5 kbar to minimize degradation.