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Proceedings Paper

CaLa2S4: Ceramic Window Material For The 8 to 14 pm Region
Author(s): William B. White; Daniel Chess; Catherine A. Chess; James V. Biggers
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Paper Abstract

CaLa2S4 is a member of the family of ternary sulfides. It has the cubic Th3P4 structure, space group I-43d, with both cations on equivalent 8-coordinated sites. Powders prepared by firing oxides and carbonates in flowing H2S can be processed by a combination of hot-pressing and hot-isostatic pressing into sulfide ceramics with good infrared transmission. The vibrational absorption edge is at 17 μm. The materials are resistant to attack by water. The microhardness of the nearly 100% dense ceramics is 600 kg/mm2. Optical transmission of 55% (including reflection losses) at 14 μm has been achieved, but optical quality is extremely sensitive to processing conditions. Absorption and scattering are produced by residual pores, by second phase impurities on grain boundaries, by oxidation products such as sulfate and thiosulfate, and electronic defects arising from non-stoichiometry.

Paper Details

Date Published: 26 February 1982
PDF: 6 pages
Proc. SPIE 0297, Emerging Optical Materials, (26 February 1982); doi: 10.1117/12.932482
Show Author Affiliations
William B. White, The Pennsylvania State University (United States)
Daniel Chess, The Pennsylvania State University (United States)
Catherine A. Chess, The Pennsylvania State University (United States)
James V. Biggers, The Pennsylvania State University (United States)

Published in SPIE Proceedings Vol. 0297:
Emerging Optical Materials
Solomon Musikant, Editor(s)

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