Water reactions of superconducting Bi2Sr2CaCu2O8 phase at O°C and ambient temperature

Stress corrosion cracking of Bi-2212 thin rods

“…This change can be related to the chemical degradation with water, 7,8 which is in agreement with an stress corrosion cracking as a process for the interpretation of the mechanical behaviour of this material. The reaction involved in this degradation mechanism, takes place in a two step process 7 The subcritical crack growth is a limitation to fracture strength in ceramics. The stable growth of cracks under applied stresses less than that for fast fracture (slow crack growth, SCG) is usually studied by means of the power-law function 11 :…”

“…12 This result is unexpected when compared with previous works on the influence of moisture in Bi-2212 bulk samples. 7,8 The water influence is so low that no marked differences in the fractured surfaces have been detected between air and water environment conditions.…”

Comparison of the behavior of the three superconductors YBCO, Bi-2212 and MgB2 in different environmental conditions

“…2 the YBCO sample presented the parasitic phases BaCO 3, BaCuO 2 and the green parasitic phase Y 2 BaCuO 5 in larger proportions than the initial sample. The increase in BaCO 3 concentration may result from the reaction of YBCO with CO 3 2− coming from the K 2 CO 3 solution. After 1 month of exposure the presence of other parasitic phases was not observed.…”

“…Among the superconducting compounds, YBa 2 Cu 3 O 7−x (YBCO), Bi 2 Sr 2 CaCu 2 O 8 (Bi-2212) and MgB 2 are of great interest in the scientific community for their future technological application and they have been extensively studied for their superconducting properties. As far as their environmental stability is referred, YBCO and BSCCO have mainly been investigated for their reaction with water at various temperatures [1][2][3] and it was found that both materials decompose when submerged into water, losing their superconducting properties. MgB 2 has also been soaked into de-ionised water, where it gradually degraded to a non-superconducting material [4] and it has been exposed to highly humid air as well [5].…”

Visualisation of environmental degradation in ceramic superconductors using digital speckle photography

“…9 After having exposed the samples to an aerated and deionised water solution for several days, it was observed that degradation problem was not associated with the Bi-2212 phase, which remained stable after 7 days in a water solution. Degradations reactions start in the (Sr,Ca)CuO 2 phase that reacts with water molecules and completely decompose in CuSr 2 (OH) 4 , CuO, SrCO 3 and Ca(OH) 2 .…”