Reactivity of RE-Ba-Cu-O superconductors with water

We studied the stability of Y-Ba-Cu-O and Gd-Ba-Cu-O against water. A variation in the superconducting and field trapping properties was measured before and after exposure to water. The YBa₂Cu₃O₇ and GdBa₂Cu₃O₇ powders were decomposed by the reaction with water in a short period. For sintered samples, grain boundaries were preferentially damaged with water. Melt-textured samples exhibited better corrosion resistance against water in that the deterioration mainly occurred at cracks. A comparison between melt-textured Gd-Ba-Cu-O samples with and without Ag addition showed that a reduction in the amount of cracking through Ag addition was effective in preventing the damage by water corrosion. The trapped field of melt-textured Gd-Ba-Cu-O with Ag addition did not deteriorate even after exposure to boiling water for 3 h.