Novel unidirectional crystallization was tested in glasses of the Bi-Sr-Ca-Cu-O system to produce highly oriented microstructures. Some evidence of liquid-liquid phase separations on cooling melts of Bi₂Sr₂Ca₁Cu₂Oₓ and Pb₀ͺ₃₂Bi₁ͺ₆₈Sr₁ͺ₇₅Ca₂Cu₃Oₓ is found for the first time from Differential Thermal Analysis (DTA), X-ray Diffraction (XRD), and Transmission Electron Microscope (TEM). This made it difficult to produce highly oriented microstructures through the present route because one of the phases in the phase separated structure is likely close to "R"-phase composition and lead to copious nucleation of "R"-phase on heating. This also resulted in sequential crystallization of the current liquids, first to "R"-phase and then to the Bi₂Sr₂Ca₁Cu₂Oₓ phase. Theoretical modelling was performed to understand general questions in the present route. The model suggests that a liquid with high interfacial energy is a good candidate for the present route to produce highly oriented microstructures. The model was tested in lithium diborate glass and showed a highly oriented microstructure. Thus, unidirectional crystallization is generally an attractive processing option for a liquid free of phase separation.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/186040 |
| Date | January 1992 |
| Creators | Kim, Seong-Jin. |
| Contributors | Uhlmann, D. R., Birnie, D. P., III, Schrimpf, R. D., O'Hanlon, J. F., Zelinski, B. J. J. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | text, Dissertation-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
Page generated in 0.0019 seconds