9.5 Conclusions This research reports on the experimental techniques and processing methods for ZBLAN crystallization suppression studies in microgravity. This experimental and processing campaign can be utilized to analyze similar materials that exhibit similar behavior, such as chalcogenide glasses and semiconductor materials that can be processed in 1-g/μ-g. Prior to this report, there were few researchers working in this area [2, 6, 7, 10, 11, 12] with minimal reporting on the experimentation, but mostly reporting that the phenomenon of ZBLAN crystallization suppression in μ-g exists. Therefore, a more detailed experimental and analytical method is needed. The experimental program included in this study describes a heating and quenching testing apparatus, known as the ‘Quencher’. The Quencher was flown on the Zero-G Corporation’s parabolic aircraft, which provided a μ-g and hyper-g environment, 1-g based tested was also completed for comparison. A detailed description of the in-flight operation was described as well as the analysis (imaging) technique used to elucidate the degree of crystallinity in the sample. The samples were analyzed using phase contrast optical microscopy. This technique confirms that crystallization is suppressed inμ-gat 360 C by showing the degree of crystallinity between each sample. In addition to the previously mentioned techniques, supplementary analysis techniques were also recommended for future studies including polarized optical microscopy, SEM, XRD, TEM, and AFM. Future work to be completed by Torres et al. is to determine the effect gravity plays on the crystallization suppression of ZBLAN glass. Acknowledgements The author’s of this work would like to thank Dr. Dennis Tucker, the Air Force Space Test Program, and NASA for their generous support of this research. References 1. Harrington JA (2007) Infrared fiber optics. In: M. Bass, J.M. Enoch, E.W. Van Stryland, and W.L. Wolfe, (eds) Handbook of Optics: Fiber and Integrated Optics, Vol. 4, Mcgraw-Hill, New York, pp 12.1–12.14 2. Tucker D (2004) Effects of gravity on ZBLAN glass crystallization. Annal NY Acad Sci 1027:129–137 3. Kundrot C (2001) Microgravity and macromolecular crystallography. Cryst Growth Design V1(1):87–99 4. Regel LL (1990) Experiments on crystallization of semiconductor materials, eutectic alloys and crystal growth from water solution in microgravity. Acta Astronaut 21(5):331–348 5. Voloshin AE (2002) Perfection and homogeneity of space-grown GaSb:Te crystals. Crystallogr Rep 47(suppl 1):S136–S148 6. Varma S (2001) Effect of gravity on crystallization in heavy metal fluoride glasses processed on the T-33 parabolic flight aircraft. J Mater Sci V36:4551–4559 7. Dunkley RI (2004) The study of devitrification processes in heavy-metal fluoride glasses. Annal NY Acad Sci V1027:150–157 8. Tucker D (1997) Effects of gravity on processing heavy metal fluoride fibers. J Mater Res V12(9):2223–2225 9. Tucker D, Ethridge E (2001) Explanation of the effects of gravity on crystallization of ZrF2-BaF2-LaF3-AlF3-NaF glass. J Mater Res 16(11):3027–3029 10. Tran DC, Siegel GH, Bendow B (1984) Heavy metal fluoride glasses and fibers: a review. J Lightwave Technol 2(5):121–138 11. Wilson SJ (1985) Observations of crystallization in fluorozirconate glasses. Mater Sci Forum 5:269–274 12. Workman G, Smith G, O’Brien S, Adcock L (1995) ZBLAN microgravity study. In: Final report submitted to national aeronautics and space administration George C. Marshall space flight center Fig. 9.9 Phase contrast optical microscopy ( 1,000): μ-g (left) and 1-g (right) 9 Characterization of a Heating and Quenching Apparatus for Microgravity Testing 73
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