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arXiv · 1110.2620

High-precision CTE measurement of hybrid C/SiC composite for cryogenic space telescopes

K. Enya·N. Yamada·T. Imai·Y. Tange·H. Kaneda·H. Katayama·M. Kotani·K. Maruyama·M. Naitoh·T. Nakagawa·T. Onaka·M. Suganuma·T. Ozaki·M. Kume·M. R. Krodel
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Abstract

This paper presents highly precise measurements of thermal expansion of a "hybrid" carbon-fiber reinforced silicon carbide composite, HB-Cesic\textregistered - a trademark of ECM, in the temperature region of \sim310-10K. Whilst C/SiC composites have been considered to be promising for the mirrors and other structures of space-borne cryogenic telescopes, the anisotropic thermal expansion has been a potential disadvantage of this material. HB-Cesic\textregistered is a newly developed composite using a mixture of different types of chopped, short carbon-fiber, in which one of the important aims of the development was to reduce the anisotropy. The measurements indicate that the anisotropy was much reduced down to 4% as a result of hybridization. The thermal expansion data obtained are presented as functions of temperature using eighth-order polynomials separately for the horizontal (XY-) and vertical (Z-) directions of the fabrication process. The average CTEs and their dispersion (1σ) in the range 293-10K derived from the data for the XY- and Z-directions were 0.805$\pm$0.003\times10$^{-6}$ K$^{-1}$ and 0.837\pm0.001\times10$^{-6}$ K$^{-1}$, respectively. The absolute accuracy and the reproducibility of the present measurements are suggested to be better than 0.01\times10$^{-6}$ K$^{-1}$ and 0.001\times(10)^{-6} K^{-1}, respectively. The residual anisotropy of the thermal expansion was consistent with our previous speculation regarding carbon-fiber, in which the residual anisotropy tended to lie mainly in the horizontal plane.

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K. Enya, N. Yamada, T. Imai, Y. Tange, H. Kaneda, H. Katayama, M. Kotani, K. Maruyama, M. Naitoh, T. Nakagawa, T. Onaka, M. Suganuma, T. Ozaki, M. Kume, M. R. Krodel. 2011-10-12. High-precision CTE measurement of hybrid C/SiC composite for cryogenic space telescopes. https://doi.org/10.1016/j.cryogenics.2011.10.004

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