Preparation and examination of Y-Ba-Cu-O wire sections

Abstract

The electrical properties of directionally solidified YBa2Cu3O7 wires have been shown to be as good as or better than any other bulk-form materials in many situations. However, the microstructural defects, including subgrain, stacking fault, and dislocation contents of these materials have not been well-characterized, in part because of the difficulty of preparing specimens for TEM examination.A new technique has been developed to prepare these wires for TEM examination. The wires were less then .7mm in diameter, making handling of cross-sections difficult. Further, adhesion of evaporated films, electroplated films,and epoxies to the wires was so poor that the wire sections would either shed the films completely, or fall out of the epoxy even when several hundred microns thick. To avoid this problem, a coating technique which adhered tightly to the wire surface was needed.