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Proceedings Paper • Open Access

Stray light reduction of silicon particle reinforced aluminum for optical systems

Paper Abstract

Silicon particle reinforced aluminum containing 42 wt.% silicon (Al-42Si) offers higher specific stiffness, higher resistance to thermal gradients, and an athermal behavior combined with electroless nickel, in comparison to state-of-the-art aluminum alloys (e.g. Al6061). Nevertheless, typical surface modifications (e.g. black anodization) lead to a nonsufficient optical stray light suppression due to the high amount of silicon particles on the surface. Therefore, a coating technique is required that fulfils the optical and the mechanical (e.g. adhesive strength) specifications for stray light reduction on Al-42Si. Different components like housings and barrels made of Al-42Si were coated with amorphous NiP and with Fractal Black by Acktar Ltd. The optical performance is analyzed by angle-resolved light scattering (ARS) at two different wavelengths (532 nm and 1064 nm). Fractal Black offers a total scattering level of lower than 2 % at 532 nm and 1064 nm. Fractal Black has been proven as a suitable coating for components made of Al-42Si.

Paper Details

Date Published: 12 July 2019
PDF: 8 pages
Proc. SPIE 11180, International Conference on Space Optics — ICSO 2018, 111802G (12 July 2019); doi: 10.1117/12.2536007
Show Author Affiliations
Jan Kinast, Fraunhofer Institute for Applied Optics and Precision Engineering (Germany)
Alexander Telle, ACM Coatings GmbH (Germany)
Sven Schröder, Fraunhofer Institute for Applied Optics and Precision Engineering (Germany)
Marcus Trost, Fraunhofer Institute for Applied Optics and Precision Engineering (Germany)
Stefan Risse, Fraunhofer Institute for Applied Optics and Precision Engineering (Germany)


Published in SPIE Proceedings Vol. 11180:
International Conference on Space Optics — ICSO 2018
Zoran Sodnik; Nikos Karafolas; Bruno Cugny, Editor(s)

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