2.10 Conclusions

It has been demonstrated that an electrochemical response of YBa₂Cu₃O_7‑x thin film and bulk pellet electrodes comparable to that of Pt can be obtained.  The two most influential factors are crystallographic orientation and the formation of a pristine electrochemical surface.   The electrical anisotropy of YBa₂Cu₃O_7‑x is manifested in the electrochemical responses of a-axis and c-axis thin films.  Inhibition of corrosion is critical to normal faradaic electron transfer.  Although the bulk properties such as the superconducting transition temperature of YBa₂Cu₃O_7‑x thin films and bulk pellets may not display the effects of corrosion upon short exposures to the atmosphere, the sensitivity of the electrochemical response at the surface reveals the damage caused by corrosion.  Therefore, steps must be taken to prevent chemical degradation.  Improved surface properties will yield more control in fundamental electron transfer studies as well as the refinements needed for the commercialization of high-temperature superconducting devices.