Vycor

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Vycor is the brand name of Corning's high-silica, high-temperature glass. It provides very high thermal shock resistance. Vycor is approximately 96% silica and 4% boron trioxide, but unlike pure fused silica, it can be readily manufactured in a variety of shapes.{{Citation needed|date=February 2024}} Vycor can be subject to prolonged usage at 900 °C.{{Cite journal |last=Nordberg |first=Martin E. |date=November 1944 |title=PROPERTIES OF SOME VYCOR-BRAND GLASSES * |url=https://ceramics.onlinelibrary.wiley.com/doi/10.1111/j.1151-2916.1944.tb14473.x |journal=Journal of the American Ceramic Society |language=en |volume=27 |issue=10 |pages=299–305 |doi=10.1111/j.1151-2916.1944.tb14473.x |issn=0002-7820|url-access=subscription }}

Vycor products are made by a multi-step process. First, a relatively soft alkali-borosilicate

glass is melted and formed by typical glassworking techniques into the desired shape. This is heat-treated, which causes the material to separate into two intermingled "phases" with distinct chemical compositions. One phase is rich in alkali and boric oxide and can be easily dissolved in acid. The other phase is mostly silica, which is insoluble. The glass object is then soaked in a hot acid solution, which leaches away the soluble glass phase, leaving an object which is mostly silica. At this stage, the glass is porous. Finally, the object is heated to more than 1200 °C, which consolidates the porous structure, making the object shrink slightly and become non-porous. The finished material is classified as a "reconstructed glass".{{Citation needed|date=February 2024}}

For some applications the final step is skipped, leaving the glass porous. Such glass has a high affinity for water and makes an excellent getter for water vapour. It is widely used in science and engineering.{{Citation needed|date=February 2024}}

Vycor has an extremely low coefficient of thermal expansion, just one quarter that of Pyrex.{{cite web |title=Properties of VYCOR Code 7913 96% Silica High Temperature Glass |url=http://csmedia2.corning.com/LifeSciences//media/pdf/Description_of_VYCOR_Code_7913.pdf |publisher=Corning Glass, Inc. |access-date=2014-12-20}} This property makes the material suitable for use in applications that demand very high dimensional stability, such as metrology instruments, and for products that need to withstand high thermal-shock loads. Vycor also has ultraviolet transmission to about 250 nm{{cite web |title=Corning Vycor® 7913 UV-Transmitting Glass |url=http://www.matweb.com/search/datasheettext.aspx?matid=748 |website=www.matweb.com |publisher=Corning |access-date=3 December 2019}} and is used in some germicidal lamps. Based on a reference thickness of 1mm, Vycor glass has an approximately 90% transmission spectra from ~300 nm to 3100 nm.{{cite web |title=VYCOR® Code 7913 Optical Transmission |url=https://www.pgo-online.com/intl/curves/vycor_kurve.html |website=Präzisions Glas & Optik GmbH |access-date=23 October 2020}}

Immersing the porous glass in certain chemical solutions before the final consolidation step produces a colored glass that can withstand high temperatures without degrading. This is used for colored glass filters for various applications.{{Citation needed|date=February 2024}}

Corning manufactures Vycor products for high-temperature applications, such as evaporating dishes.{{Citation needed|date=February 2024}}

Porous vycor is a prototypical matrix material for the study of confined liquid physics.{{Citation needed|date=February 2024}}

Vycor can also be used for removal of ²³¹Pa and ²³³Pa in fuel recycling.{{Cite report |url=http://dx.doi.org/10.2172/4347358 |title=ADSORPTION OF PROTACTINIUM ON UNFIRED VYCOR: FINAL HOT-CELL EXPERIMENTS. |last1=Goode |first1=J. H. |last2=Moore |first2=J. G. |date=1967-01-01 |publisher=Office of Scientific and Technical Information (OSTI)|doi=10.2172/4347358 }}