ABSTRACT
Thallium-based high-temperature superconductors have been prepared via spray pyrolysis by dissolving all the precursor compounds into solution and by diffusing vapor-transported thallium oxide into a precursor film. In this chapter, the authors describe experimental findings from laboratory and the literature to identify key process parameters and how variations to these parameters can affect the quality of spray-pyrolyzed films. They also examine how different techniques that fit loosely into the general definition of spray pyrolysis could conceivably be used to improve on the process. The predominant use of nitrate salts in spray pyrolysis has allowed researchers to infer the relative effects of rheological influences on the ultimate quality of spray-pyrolyzed films. Finally, in view of the ability for the thallium-based superconductors to sustain high critical current densities even in a poly crystalline state, it appears to be a material system that is very well suited to commercial bulk production using a process as simple and cost-effective as spray pyrolysis.
