Origin and Manufacturing
- Fused quartz is produced by melting naturally occurring quartz crystals or high-purity quartz sand. Methods include flame fusion or electric arc furnacing in dry environments, which yield a product with very low hydroxyl (OH) content.
- Fused silica is manufactured synthetically. One common method involves flame hydrolysis of silicon tetrachloride (SiCl4), resulting in ultra-high purity glass with a more homogeneous structure and typically higher OH content. The synthetic process minimizes metallic and ionic contaminants, making fused silica ideal for semiconductor and deep-UV optical applications.
Impurity and Hydroxyl (OH) Content
Key Properties
Both fused silica and fused quartz exhibit:
-
High thermal stability
-
Exceptional UV-to-IR transparency
-
Low coefficient of thermal expansion (~0.5 x 10^-6/K)
-
Excellent chemical resistance
-
High resistance to radiation and devitrification (Hertel et al., 2016)
However, subtle distinctions make each suitable for different applications:
-
Fused silica is preferred for precision optics and UV transmission.
-
Fused quartz is widely used in furnace tubes, labware, and lamp envelopes due to its thermal shock resistance and lower cost.
Research Findings
A 2016 study by Hertel et al. highlighted the performance of synthetic fused silica domed windows in solar thermal receivers, where thermal cycling stability and devitrification resistance are critical. The material demonstrated exceptional durability under high temperature and pressure, maintaining optical clarity and structural integrity even in demanding solar energy environments.
Similarly, Guerra et al. (2014) examined bubble formation in fused silica produced from Brazilian quartz powder using flame fusion. They found that acid-leached feedstock significantly reduced bubble defects, achieving optical quality comparable to imported high-purity fused quartz. The findings reinforce the importance of pre-treatment and purity control in achieving superior optical and mechanical performance for high-temperature or high-precision applications.
Comparative Summary Table
| Property / Aspect | Fused Quartz | Fused Silica |
|---|---|---|
| Source Material | Natural quartz sand / crystals | Synthetic (e.g., SiCl₄ flame hydrolysis) |
| Manufacturing Process | Flame or electric fusion | Chemical vapor deposition / flame hydrolysis |
| Purity (metallic) | Moderate (ppm level) | Very high (ppb–low ppm) |
| OH Content | Low (5–30 ppm, depending on method) | High (up to 1000 ppm, unless treated) |
| Thermal Shock Resistance | High | High |
| UV Transmission | Good | Excellent (better deep-UV) |
| IR Absorption | Lower (better for IR if low OH) | Higher (OH increases IR absorption) |
| Cost | Lower | Higher |
| Applications | Lamps, labware, furnace parts | Lithography, precision optics, semiconductors |
Conclusion
Fused quartz and fused silica both offer unique advantages depending on the application. The key distinctions come from their manufacturing process and impurity levels:
-
Fused silica: Synthetic, ultra-pure, higher OH, ideal for optical and semiconductor uses.
-
Fused quartz: Natural source, lower OH with proper treatment, better for thermal and structural applications.
A thorough understanding of these differences allows for informed material selection tailored to performance needs.
Goodfellow Fused Quartz & Fused Silica in Research
Material |
Mentions |
|
| Fused Quartz | López‐Cuevas J, Jones H, Atkinson HV. Wettability of silica substrates by silver–copper based brazing alloys inVacuo. Journal of the American Ceramic Society. 2000 Dec;83(12):2913-8. | Research Paper Link |
| Lassaletta G, Fernandez A, Espinos JP, Gonzalez-Elipe AR. Spectroscopic characterization of quantum-sized TiO2 supported on silica: influence of size and TiO2-SiO2 interface composition. The Journal of Physical Chemistry. 1995 Feb;99(5):1484-90. | Research Paper Link | |
| Fused Silica | Yimnirun R, Moses PJ, Newnham RE, Meyer Jr RJ. Electrostrictive strain in low-permittivity dielectrics. Journal of electroceramics. 2002 Aug;8(2):87-98. | Research Paper Link |
| Ahmad FN, Jaafar M, Palaniandy S, Azizli KA. Effect of particle shape of silica mineral on the properties of epoxy composites. Composites Science and technology. 2008 Feb 1;68(2):346-53. | Research Paper Link | |
| Waugh DG, Walton CD. Micro-machining of diamond, sapphire and fused silica glass using a pulsed nano-second Nd: YVO4 laser. Optics. 2021 Aug 23;2(3):169-83. | Research Paper Link | |
References
- Guerra, C. P., Ono, E. A., Santos, M. F. M. dos, & Suzuki, C. K. (2014). Study of bubbles elimination in silica glass produced by flame fusion from Brazilian natural quartz powder. Materials Science Forum, 798-799, 375–380. https://doi.org/10.4028/WWW.SCIENTIFIC.NET/MSF.798-799.375
- Hertel, J., Uhlig, R., Söhn, M., Schenk, C., Helsch, G., & Bornhöft, H. (2016). Fused silica windows for solar receiver applications. AIP Conference Proceedings, 1734(1), 110002. https://doi.org/10.1063/1.4949072
- Kazuyoshi, A., Takahata, T., Hasimoto, S., Masato, U., Yamada, N., Harada, Y., & Horikoshi, H. (2007). Fused quartz glass and process for producing the same.Patent. https://patents.google.com/patent/EP2070883B1/en
- Kuzuu, N. (1998). Properties of silica glass: Effect of terminal structures and granular structure. Japanese Journal of Applied Physics, 37(S1), 28–30. https://doi.org/10.7567/JJAPS.37S1.28
