Abstract
We investigated the degradation of critical current density (Jc) and irreversibility field (Hirr) of pure and Ti-doped MgB2 bulks by exposing the samples to water for a total of 10, 48, 100, and 124 h. We found that both Jc and Hirr of the samples were degraded by exposure to water, in various degrees depending on the doping level. In the same exposure duration, the Ti-doped samples exhibited a less sensitivity to water, which was confirmed by the less degradation of Jc and Hirr. Our results demonstrate that Ti doping is not only effective in improving the superconducting properties of MgB2 but also in enhancing its chemical stability against water.