Talk:Zerodur

CTE values
The data presented for the CTE is all over the place. It is present 3 times and is different each time. Can someone come up with a value and make sure it is all correct??

KAW 73.213.29.16 (talk) 16:59, 30 June 2015 (UTC)

External links modified
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I have just modified 3 one external links on Zerodur. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added archive http://web.archive.org/web/20110724234153/http://www.unitedlens.com:80/page175.html to http://www.unitedlens.com/page175.html
 * Added archive http://web.archive.org/web/20140201215054/http://www.schott.com/advanced_optics/english/syn/advanced_optics/products/optical-materials/zerodur-zero-expansion-glass-ceramic/zerodur/index.html?so=uk&lang=english to http://www.schott.com/advanced_optics/english/syn/advanced_optics/products/optical-materials/zerodur-zero-expansion-glass-ceramic/zerodur/index.html?so=uk&lang=english
 * Added archive http://web.archive.org/web/20131004223930/http://www.schott.com/advanced_optics/english/syn/advanced_optics/products/optical-materials/zerodur-zero-expansion-glass-ceramic/zerodur/index.html to http://www.schott.com/advanced_optics/english/syn/advanced_optics/products/optical-materials/zerodur-zero-expansion-glass-ceramic/zerodur/index.html

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New Lead Section
Hi all, I’d like to propose an edit to address the “lead section may need to be rewritten” issue. This new version is more concise, and focuses on what Zerodur is, its main feature, and where it is used. The rest doesn't seem relevant for the lead section to me. The list of specific telescopes could go in the Applications section (I'll follow up on that later), and the last 3 sentences ("Although it has advantages ...") lack a citation, so I've removed them.

Zerodur is a lithium-aluminosilicate glass-ceramic produced by Schott AG since 1968. It has been used for a number of very large telescope mirrors including GTC, Keck I, Keck II, and SOFIA, as well as some smaller telescopes (such as the GREGOR Solar Telescope). With its low coefficient of thermal expansion (CTE), it is suitable for producing mirrors that maintain acceptable figures in extremely cold environments, such as deep space. Although it has advantages for applications requiring a coefficient of thermal expansion less than that of borosilicate glass, it remains very expensive as compared to borosilicate. The tight tolerance on CTE, ±0.007 K−1, allows for its use in high-precision applications.

Zerodur is a lithium-aluminosilicate glass-ceramic manufactured by Schott AG. Zerodur has a near zero coefficient of thermal expansion (CTE), and is used for high-precision applications in telescope optics, microlithography machines and inertial navigation systems.

Thanks for your consideration, and let me know if you have any feedback! Elisabeth at SCHOTT (talk) 12:25, 10 July 2024 (UTC)
 * Thank you for going through the COI request process! Feel free to tag me when re-adding the specific telescopes, I can't guarantee I'll get to it but I'll try to take a look. Rusalkii  (talk) 20:54, 11 July 2024 (UTC)
 * @Rusalkii, thank you for your quick review! I just wanted to let you know that I've added the expanded Applications section where I've added back in some telescope examples, among others. See below. Regards, Elisabeth at SCHOTT (talk) 13:35, 12 July 2024 (UTC)

Revised Properties Section
Hi all, I’d like to propose some changes to address the “written like an advertisement” issue. I am not entirely sure what the user's issue with the article was, but I presume it is refering to some "better than" comparsions to other materials and products, mentioned in the Properties section. To improve the neutrality of the article, I'm proposing a version that removes those superiority claims. Thanks for taking a look at this proposal, and let me know if you have any input or other thoughts! Elisabeth at SCHOTT (talk) 12:40, 10 July 2024 (UTC) {{TextDiff|

Properties
Zerodur has both an amorphous (vitreous) component and a crystalline component. Its most important properties are:
 * The material exhibits a particularly low thermal expansion, with a mean value of 0 ± 0.007×10−6 K−1 within the temperature range of 0 to 50 °C. This thermal expansion performance is comparatively superior to that of fused quartz by two orders of magnitude.
 * High 3D homogeneity with few inclusions, bubbles and internal stria (as contrasted to Cer-Vit).
 * Hardness similar to that of borosilicate glass, so that it can be ground and polished more easily than fused quartz.
 * High affinity for coatings.
 * Low helium permeability.
 * Non-porous (as contrasted to sintered ceramics).
 * Good chemical stability similar to that of fused quartz.
 * Fracture toughness approximately 0.9 MPa·m1/2.

Properties
Zerodur has both an amorphous (vitreous) component and a crystalline component. Its most important properties are: }} Elisabeth at SCHOTT (talk) 12:40, 10 July 2024 (UTC)
 * The material exhibits a particularly low thermal expansion, with a mean value of 0 ± 0.007×10−6 K−1 within the temperature range of 0 to 50 °C.
 * High 3D homogeneity with few inclusions, bubbles and internal stria.
 * Hardness similar to that of borosilicate glass.
 * High affinity for coatings.
 * Low helium permeability.
 * Non-porous.
 * Good chemical stability.
 * Fracture toughness approximately 0.9 MPa·m1/2.


 * ✅ @Elisabeth at SCHOTT, thank you for going through the COI edit process. Rusalkii  (talk) 20:42, 11 July 2024 (UTC)

Revised Applications Section
Hi all, I've drafted a new version of the section, in which I've expanded on the application areas including some relevant examples, e.g., the telescopes that I previously removed when I shortened the lead section (see above). Thank you very much for your review! -- Elisabeth at SCHOTT (talk) 13:31, 12 July 2024 (UTC)

Proposed Version for Applications


The main applications for Zerodur include telescope optics in astronomy and space applications, lithography machines for microchips and displays, and inertial measurements systems for navigation.

In astronomy, it is used for mirror substrates in large telescopes such as the Hobby-Eberly Telescope, the Keck I and Keck II telescopes, the Gran Telescopio Canarias, the Devasthal Optical Telescope, the European Southern Observatory's 8.2 m Very Large Telescope, and the 39 m Extremely Large Telescope.

In space, it has been used for the primary mirror of SOFIA’s telescope, for the imager in Meteosat Earth observation satellites, and for the optical bench in the LISA Pathfinder mission.

In microlithography, Zerodur is used in wafer steppers and scanner machines for precise and reproducible wafer positioning. It is also used as a mirror substrate material in refractive optics for EUV lithography.

In inertial measurement units, Zerodur is used in ring laser gyroscopes.

Elisabeth at SCHOTT (talk) 13:31, 12 July 2024 (UTC)
 * , for future reference you want to use the template to consolidate references from one talk page section. I've edited this and the above section to use it.  Rusalkii  (talk) 22:01, 12 July 2024 (UTC)