Influence of silver addition on cracking in melt-grown YBCO

• Published in: Physica. C, Superconductivity Vol. 363; no. 1; pp. 60 - 66
• Main Authors: Diko, P., Fuchs, G., Krabbes, G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2001
• Subjects: Ag addition; Cracking; Melt processing; Microstructure; YBCO; 74.80.Bj; 61.72.−y; Melt processing; Cracking; 74.72.Bk; Ag addition; YBCO; Microstructure; 81.30.Fb
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/S0921-4534(01)00622-0

The influence of silver addition on a– b microcracking and c-cracking in melt-grown YBa 2Cu 3O 7/Y 2BaCuO 5 single-grain superconductors of nominal composition YBa 2Cu 3O 7+0.24Y 2O 3+0.02Pt was studied by optical microscopy. The spacing of the a– b microcracks increased from 1.8 to 3.7 μm and the spacing of the c-cracks increased from 34.2 to 133.5 μm when 12 wt.% Ag was added. This behavior can be associated with microstresses introduced by Ag particles. Higher volume change of the Ag than of the YBa 2Cu 3O 7/Y 2BaCuO 5 matrix during cooling down from the processing temperature and during oxygenation causes compressive tangential stresses around Ag particles and therefore cracking is suppressed. This suppression of cracking by Ag particles leads to slower oxidation of YBa 2Cu 3O 7/Y 2BaCuO 5 single-grain superconductors.