Fused quartz is an extraordinary material for numerous industrial applications. The single-component glass consists solely of silica (SiO2). Through its unique combination of thermal, mechanical and optical properties, fused quartz is one of the most important materials for industry and research.
For the Semiconductor an Solar industries, fused quartz is used in high temperature processes because of its high softening point, low thermal expansion and excellent thermal shock resistance. It can withstand temperatures up to 1300°C and can be rapidly heated and cooled with virtually no risk of breakage. Because of its high purity, parts and systems made of fused quartz are ideal suited for industry equipment.
For the Lighting industry, fused quartz is an indispensable material due to the high optical transmission from ultraviolet through the infrared light.
For the Chemical industry and for laboratory equipmentation, fused quartz is used because of its resistance to acids, bases and water. With the exception of hydrofluoric acid, phosphoric acid, and alkaline compounds its properties are unaffected.
For the Electronics industry, fused quartz is characterized by high dielectric strength, low electrical conductivity and superior microwave transmission even at high temperatures.
Critical to the efficient transmission of light, clear fused quartz contains very low levels of impurities (as measured in parts per million). This single component glass is further distinguished from other glass material by a very high transmission of ultra violet light. The higher the purity of the material, the higher the transmittance in UV-range. For this reason, synthetically manufactured fused quartz materials show the highest transmission for ultraviolet light.
The light transmission of fused quartz may be reduced or even extinguished when the material is exposed to high-energy UV-radiation, X-rays, gamma rays and particle bombardment.
Mechanical property measurements are dependent upon geometry, thermal gradient and surface quality. For proper strength calculations, the lower pressure variable should be used.
|Density||2,20g/cm3||Bending Strength||68 N/mm2|
|Compressive Strength||1150 N/mm2||Elasticity modulus||7,5x104 N/mm2|
|Tensile Strength||50N/mm2||Mohs Hardness||5,5-6,5|
|Dielectric loss factor|
(at a frequency of 7,5 GHz)
|tg δ ≈ 5 x 10-4|
|Dielectric constant||ε ≈ 3,7 |
(at 20 °C / 7,5 GHz)
250 - 400 kV / cm
|Specific electrical resistance |
at different temperatures:
|at 20°C||1018 Ωm|
|at 100°C||1016 Ωm|
|at 200°C||4x1013 Ωm|
|at 400°C||1010 Ωm|
|at 800°C||6,3x106 Ωm|
|at 1000°C||106 Ωm|
|at 1200°C||1,3x106 Ωm|
Hydrolytic resistance per DIN 12111 ( 1.class)
Acid resistance per DIN 12116 ( 1.class)
Alkaline resistance per DIN 52322 ( 1.class)
ilmasil® PO 1 /
ilmasil® PN 235
ilmasil® PN 350
|Transformation Range||1075 - 1210°C|
at lg h (in dPas) = 5 - 8
Max. Usable Temperature
|Coefficient of Thermal Expansion|
|ca. 5,5 x 10-7 / °C|
Devitrification is dependent upon surface cleanliness, atmospheric conditions and temperature cycling. Below 1025°C devitrification takes place very slowly, but above 1425°C devitrification is rapid. If heating cycles take the product above 1025°C , devitrification will be minimized if a minimum temperature of 250°C is maintained.
< 2,5 µl gas/g under vacuum at 1000°C.
Basis for the determination is the OH- absorption band at 2,73 µm. A sample is tested by Infrared -spectrometer in the range of 2,5 - 3 µm.
|COH = 0,1 x log (I0 / I) x 1/d x 104||COH||OH-content in ppm|
|I0||Basic Intensity at 2,73 µm|
|I||Intensity of maximum absorption|
|d||sample thickness in mm|
|Coefficient of extinction: 77,5 l / Mol cm|
Fused quartz requires care in handling and use to achieve good performance. Cleanliness will help reduce devitrification and maximize the life of this material. Handle fused quartz with care and only with clean cotton gloves to avoid contamination . Wrap and store quartz in a clean, dry environment
1. Cleaning with non-alkali cleaning agent and/or isopropyl alcohol.
2. Rinse with deionized (distilled) water
3. Air dry in clean environment and clean wrapping