Degradation behavior of MgB2 superconductor

The degradation behavior of polycrystalline MgB2 superconductor, exposed to water and ambient atmosphere, has been studied. We have found that prolong ed exposure to water completely destroys superconductivity. Optical microsc opic and X-ray diffraction analyses indicate that, on exposure to water, th e material becomes amorphous like. X-ray photoelectron spectroscopic measur ements reveal the strongly hygroscopic character of MgB2 and we have found that, even at room temperature, water and air change it into Mg(OH)(2), MgC O3 and B2O3. (C) 2001 Elsevier Science B.V. All rights reserved.