Properties of Fused Quartz
Properties of Fused Quartz
Silica is found almost everywhere in nature, and represents almost 1/3 the mass of the earth’s crust. Vitreous Silica is the generic term used to describe all types of silica glass, and manufacturers refer to the material as either Fused Quartz or Fused Silica.
Fused Quartz is manufactured by melting naturally occurring crystalline silica, such as sand or rock crystal. The production method is either electrically fused or flame fused. Afterward, items will appear transparent, translucent, or opaque; making it possible to create a wide range of products.
Fused silica, commonly referred to as synthetic fused quartz, is produced using high purity silica sand that is manufactured from SiCL4. The finished product is a transparent glass with an ultra-high purity and improved optical transmission.
Vitreous Silica, in all its forms, offers a variety of properties such as:
- Permeability
- Extreme Hardness
- Very Low Coefficient of Thermal Expansion
- Resistance to High Temperature
- High Chemical Purity
- High Corrosion Resistance
- Extensive Optical Transmission from Ultra-Violet to Infra-Red
- Excellent Electrical Insulation Qualities
- Remarkable Stability Under Atomic Bombardment
PROPERTY |
TYPICAL VALUES |
|---|---|
| Density | 2.2 x 103 kg/m3 |
| Hardness | 5.5–6.5 Mohs’ Scale |
| 570 KHN100 | |
| Design Tensile Strength | 4.8 x 107 Pa (N/m2) (7,000 psi) |
| Design Compressive Strength | >1.1 x 109 Pa (160,000 psi) |
| Bulk Modulus | 3.7 x 1010 Pa (5.3 x 106 psi) |
| Rigidity Modulus | 3.1 x 1010 Pa (4.5 x 106psi) |
| Young’s Modulus | 7.2 x 1010 Pa (10.5 x 106 psi) |
| Poisson’s Ratio | 0.17 |
| Coefficient of Thermal Expansion (20°C–320°C) | 5.5 x 10-7 cm/cm °C |
| Thermal Conductivity (20°C) | 1.4 W/m °C |
| Specific Heat (20°) | 670 J/kg °C |
| Softening Point | 1683°C |
| Annealing Point | 1215°C |
| Strain Point | 1120°C |
| Electrical Resistivity | 7 x 107 ohm cm at 350°C |
| Dielectric Loss Factor | <0.0004 at 20°C and 1 MHz |
| Dielectric Constant | 3.75 at 20°C and 1 MHz |
| Dielectric Strength | 5 x 107 V/m at 20°C and 1 MHz |
| Dissipation Factor | <0.0001 at 20°C and 1 MHz |
| Index of Refraction | 1.4585 |
| Constringence (Nu value) | 67.56 |
| Velocity of Sound-Shear Wave | 3.75 x 103 m/s |
| Velocity of Sound/Compressional Wave | 5.90 x 103 m/s |
| Sonic Attentuation | <11dB/m MHz |
| Permeability Constants (700°C) | |
| Helium | 2.1 x 10-8 cm3 mm/cm2 sec. cm Hg |
| Hydrogen | 2.1 x 10-9 cm3 mm/cm2 sec. cm Hg |
| Deutrium | 1.7 x 10-9 cm3 mm/cm2 sec. cm Hg |
| Neon | 9.5 x 10-10 cm3 mm/cm2 sec. cm Hg |
