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Proceedings Paper

NT-SiC (new-technology silicon carbide) : Φ 650mm optical space mirror substrate of high-strength reaction-sintered silicon carbide
Author(s): Shoko Suyama; Yoshiyasu Itoh; Katsuhiko Tsuno; Kazuhiko Ohno
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Paper Abstract

Silicon carbide (SiC) is the most advantageous as the material of various telescope mirrors, because of high stiffness, low density, low coefficient of thermal expansion, high thermal conductivity and thermal stability. Newly developed high-strength reaction-sintered silicon carbide (NTSIC), which has two times higher strength than sintered SiC, is one of the most promising candidates for lightweight optical mirror substrate, because of fully dense, lightweight, small sintering shrinkage (±1 %), good shape capability and low processing temperature. In this study, 650mm in diameter mirror substrate of NTSIC was developed for space telescope applications. Three developed points describe below. The first point was to realize the lightweight to thin the thickness of green bodies. Ribs down to 3mm thickness can be obtained by strengthen the green body. The second point was to enlarge the mirror size. 650mm in diameter of mirror substrate can be fabricated with enlarging the diameter in order. The final point was to realize the homogeneity of mirror substrate. Some properties, such as density, bending strength, coefficient of thermal expansion, Young's modulus, Poisson's ratio, fracture toughness, were measured by the test pieces cutting from the fabricated mirror substrates.

Paper Details

Date Published: 23 August 2005
PDF: 10 pages
Proc. SPIE 5868, Optical Materials and Structures Technologies II, 58680E (23 August 2005); doi: 10.1117/12.616043
Show Author Affiliations
Shoko Suyama, Toshiba Corp. (Japan)
Yoshiyasu Itoh, Toshiba Corp. (Japan)
Katsuhiko Tsuno, NEC TOSHIBA Space Systems, Ltd. (Japan)
Kazuhiko Ohno, NEC TOSHIBA Space Systems, Ltd. (Japan)

Published in SPIE Proceedings Vol. 5868:
Optical Materials and Structures Technologies II
William A. Goodman, Editor(s)

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