The microstructural evolution of silver-containing spray deposited 1223 Tl--Ca--Ba--Cu oxide superconductor
- Corporate Research and Development Center, P. O. Box 8, General Electric Company, Schenectady, New York 12301 (United States)
- Oak Ridge National Labs, Oak Ridge, Tennessee 37831 (United States)
This paper reports a study of the microstructural evolution of Ag-containing 1223 Tl--Ca--Ba--Cu oxide superconductors in spray-deposited films. The films were formed by spray depositing nitrates of Ca, Ba, Cu, and Ag onto a polycrystalline yttria-stabilized zirconia substrate. These deposits were then converted to a mixture of oxides (calcia, calcium-copper oxide, and barium cuprate) and metallic silver by heating in oxygen. When thallium oxide vapor was passed over the film, the thallium was incorporated into the film and the 1223 phase was formed. The evidence strongly suggests that the development of the 1223 superconductor involves the formation of a liquid phase. Our analysis suggests that the initial phase to form a liquid is CaO that contains thallium, barium, copper, and silver. Once this initial liquid is formed, it incorporates more thallium which, in turn, allows it to dissolve other types of oxides present in the film. In this way the liquid spreads across the surface. The equilibrium 1223 phase precipitates from it.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- AC05-84OR21400; W-31109-ENG-38
- OSTI ID:
- 46448
- Journal Information:
- Journal of Materials Research, Vol. 10, Issue 4; Other Information: PBD: Apr 1995
- Country of Publication:
- United States
- Language:
- English
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