Fused quartz
Fused quartz, fused silica or quartz glass is a
The terms fused quartz and fused silica are used interchangeably but can refer to different manufacturing techniques, resulting in different trace impurities. However fused quartz, being in the glassy state, has quite different physical properties compared to crystalline quartz despite being made of the same substance.[2] Due to its physical properties it finds specialty uses in semiconductor fabrication and laboratory equipment, for instance.
Compared to other common glasses, the optical transmission of pure silica extends well into the
Manufacture
Fused quartz is produced by fusing (melting) high-purity silica sand, which consists of quartz crystals. There are four basic types of commercial silica glass:
- Type I is produced by induction melting natural quartz in a vacuum or an inert atmosphere.
- Type II is produced by fusing quartz crystal powder in a high-temperature flame.
- Type III is produced by burning SiCl4 in a hydrogen-oxygen flame.
- Type IV is produced by burning SiCl4 in a water vapor-free plasma flame.[4]
Quartz contains only silicon and oxygen, although commercial quartz glass often contains impurities. Two dominant impurities are
Fusion
Melting is effected at approximately 2200 °C (4000 °F) using either an electrically heated furnace (electrically fused) or a gas/oxygen-fuelled furnace (flame-fused).
Product quality
Fused quartz is normally transparent. The material can, however, become translucent if small air bubbles are allowed to be trapped within. The water content (and therefore infrared transmission) of fused quartz is determined by the manufacturing process. Flame-fused material always has a higher water content due to the combination of the hydrocarbons and oxygen fueling the furnace, forming
Applications
Many optical applications of fused quartz exploit its wide transparency range, which can extend well into the ultraviolet and into the near-mid infrared. Fused quartz is the key starting material for optical fiber, used for telecommunications.
Because of its strength and high melting point (compared to ordinary
Because of its physical strength, fused quartz was used in deep diving vessels such as the bathysphere and benthoscope and in the windows of crewed spacecraft, including the Space Shuttle and International Space Station.[8] Fused quartz was used also in composite armour development.[9]
In the semiconductor industry, its combination of strength, thermal stability, and UV transparency makes it an excellent substrate for
Due to the thermal stability and composition, it is used in 5D optical data storage[12] and in semiconductor fabrication furnaces.[13][14]
Fused quartz has nearly ideal properties for fabricating
Fused quartz can be metallised and etched for use as a substrate for high-precision microwave circuits, the thermal stability making it a good choice for narrowband filters and similar demanding applications. The lower
Refractory material applications
Fused quartz as an industrial raw material is used to make various refractory shapes such as crucibles, trays, shrouds, and rollers for many high-temperature thermal processes including
Owing to its low mechanical damping at ordinary temperatures, it is used for
Quartz glassware is occasionally used in chemistry laboratories when standard borosilicate glass cannot withstand high temperatures or when high UV transmission is required. The cost of production is significantly higher, limiting its use; it is usually found as a single basic element, such as a tube in a furnace, or as a flask, the elements in direct exposure to the heat.
Properties of fused quartz
The extremely low coefficient of thermal expansion, about 5.5×10−7/K (20–320 °C), accounts for its remarkable ability to undergo large, rapid temperature changes without cracking (see thermal shock).
Fused quartz is prone to
"Infrared grade" fused quartz (tradenames "Infrasil", "Vitreosil IR", and others), which is electrically fused, has a greater presence of metallic impurities, limiting its UV transmittance wavelength to around 250 nm, but a much lower water content, leading to excellent infrared transmission up to 3.6 μm wavelength. All grades of transparent fused quartz/fused silica have nearly identical mechanical properties.
Refractive index
The optical dispersion of fused quartz can be approximated by the following Sellmeier equation:[17]
where the wavelength is measured in micrometers. This equation is valid between 0.21 and 3.71 μm and at 20 °C.[17] Its validity was confirmed for wavelengths up to 6.7 μm.[4] Experimental data for the real (refractive index) and imaginary (absorption index) parts of the complex refractive index of fused quartz reported in the literature over the spectral range from 30 nm to 1000 μm have been reviewed by Kitamura et al.[4] and are available online.
Its quite high
List of physical properties
- Density: 2.203 g/cm3
- Hardness: 5.3–6.5 (Mohs scale), 8.8 GPa
- Tensile strength: 48.3 MPa
- Compressive strength: > 1.1 GPa
- Bulk modulus: ~37 GPa
- Rigidity modulus: 31 GPa
- Young's modulus: 71.7 GPa
- Poisson's ratio: 0.17
- Lamé elastic constants: λ = 15.87 GPa, μ = 31.26 GPa
- Coefficient of thermal expansion: 5.5 × 10−7/K (average 20–320 °C)
- Thermal conductivity: 1.3 W/(m·K)
- Specific heat capacity: 45.3 J/(mol·K)
- Softening point: ≈ 1665 °C
- Annealing point: ≈ 1140 °C
- Strain point: 1070 °C
- Electrical resistivity: > 1018 Ω·m
- Dielectric constant: 3.75 at 20 °C 1 MHz
- Dielectric loss factor: less than 0.0004 at 20 °C 1 MHz typically 6 × 10−5 at 10 GHz[18]
- Dielectric strength: 250–400 kV/cm at 20 °C[19]
- Magnetic susceptibility: −11.28 × 10−6 (SI, 22 °C)[20]
- Hamaker constant: A = 6.5 × 10−20 J.
- Surface tension: 0.300 N/m at 1800–2400 °C[21]
- Index of refraction: nd = 1.4585 (at 587.6 nm)
- Change of refractive index with temperature: 1.28 × 10−5/K (20–30 °C)[17]
- Transmission range: Cutoff – 160 to 5000 nm, with a deep absorption line at 2730 nm. Best transmittance – 180 to 2700 nm.[22]
- Stress-optic coefficients: p11 = 0.113, p12 = 0.252.
- Abbe number: Vd = 67.82[23]
See also
References
- ^ Hardwood, W. (20 April 2004). "Spacecraft launched to test Albert Einstein's theories". Spaceflight Now. Retrieved 14 May 2009.
- ^ "Quartz vs. Fused Silica: What's the Difference?". Swift Glass. 2015-09-08. Retrieved 2017-08-18.
- ISBN 3-527-30673-0.
- ^ S2CID 17169097. Retrieved 2014-07-12.
- ^ Chemical purity of fused quartz / fused silica, www.heraeus-quarzglas.com
- OCLC 1101101049.)
{{cite book}}
: CS1 maint: location missing publisher (link - ^ "Fused quartz - Acemap". ddescholar.acemap.info. Retrieved 2023-07-04.
- ^ Salem, Jonathan (2012). "Transparent Armor Ceramics as Spacecraft Windows". Journal of the American Ceramic Society.
- ^ Evaluation of Siliceous Cored Armor for the XM60 Tank Archived June 5, 2011, at the Wayback Machine
- ^ "Intel 1702A 2K (256 x 8) UV Erasable PROM" (PDF).
- ^ "CPU History - EPROMs". www.cpushack.com. Retrieved 2021-05-12.
- ^ Kazansky, P.; et al. (11 March 2016). "Eternal 5D data storage via ultrafast-laser writing in glass". SPIE Newsroom.
- ^ "Fused Quartz and Silica Plates for Semiconductor Applications". Heraeus Holding GmbH. Retrieved 2022-08-07.
- ^ "Quartz Properties". finkenbeiner.com. Retrieved 2022-08-07.
- ^ An Overview of MEMS Inertial Sensing Technology, February 1, 2003
- S2CID 11630697.
- ^ . Retrieved 2014-07-12.
- ^ "Keysight Technologies GENESYS Concepts" (PDF). Keysight Technologies.
- ^ "Fused Silica". OpticsLand. Archived from the original on 2013-06-02. Retrieved 2016-02-27.
- S2CID 11545416.
- ^ Surface tension and viscosity measurement of optical glasses using a scanning CO2 laser
- ^ Optical Engineering Science by Stephen Rolt - Wiley Publishing 2020 Page 211-213
- ^ "Refractive Index of Fused Silica (Fused Quartz)". Refractive Index. Retrieved 2017-08-18.
External links
- "Frozen Eye to Bring New Worlds into View" Popular Mechanics, June 1931 General Electrics, West Lynn Massachusetts Labs work on large fuzed quartz blocks