Improvement of the mechanical properties of bulk superconductors with resin impregnation

摘要

Large single-grain RE-Ba-Cu-O (RE:rare-earth elements) superconductors can trap largemagnetic fields over several tesla, and thus can beused as quasi-permanent magnets, generating fieldsmuch higher than those of conventional permanentmagnets. However, the maximum trapped field isessentially limited by the mechanical properties ofbulk superconductors, since a large electromagneticforce acts on the bulks when they trap large fields.The stress produced by refrigeration also causes cracking.We have recently found that epoxy resin can penetrate into bulksuperconductors under appropriate conditions. Microstructuralobservations revealed that microcracks as well as macrocracksor porosities can be impregnated with epoxy resin, which greatlyimproves the mechanical properties of bulk RE-Ba-Cu-Osuperconductors and thus results in the improvement of theirfield-trapping capability