Effect of resin impregnation on the mechanical properties of bulk-superconductors

We have recently succeeded in improving the mechanical properties of bulk Y-Ba-Cu-O superconductors through resin impregnation. In order to clarify the effect of resin impregnation on the mechanical properties, we first measured the adhesive force between resin and bulk superconductors using the tensile test. It was found that the adhesive force is larger than the strength of bulk materials. We also measured the rupture strength of Y-Ba-Cu-O rods having artificial groove filled with and without epoxy resins using a three point bending test. The rupture strength was reduced by introducing the groove. In contrast, the sample with the groove filled with resin exhibited higher rupture strength than that of virgin bulk materials, These results suggest that the improvement of mechanical property through resin impregnation is ascribed to the prevention of crack propagation along the cleavage plane due to the presence of resin.