Fused silica石英玻璃

Fused silica

Fused silica

Fused Silica is the glassy form of quartz and is thus isotropic. It is tough and hard and has a very low expansion. Normal varieties contain water that gives strong absorption in the IR. Water-free varieties are available.

Fused Silica includes three types: JGS1 (Ultraviolet Grade Fused Silica),JGS2 (Optical Grade Fused Quartz), and JGS3 (Full Spectrum Fused Silica).

Today advances in raw material beneficiation permit transparent fusions from sand as well as from crystal. Consequently, if naturally occurring crystalline silica (sand or rock) is melted, the material is simply called Fused Quartz. If the silicon dioxide is synthetically derived, however, the material is referred to as synthetic Fused Silica.

These materials are ultra pure, single component glasses (SiO2) with a unique combination of thermal, optical and mechanical properties, which make them the preferred materials for use in a variety of processes and applications where other materials are not suitable. The very high purity (over 99.9%) ensures minimum contamination in process applications.

Fused Quartz is less expensive vitreous silica formed by fusing naturally occurring quartz crystal or lower grade synthetic stock material, The UV use is limited to 250nm and this material is usually used for windows covering visible wavelengths.

Fused Silica is vitreous silica formed by fusing high purity synthetic material. The UV use can be reached about 160nm.

Ultraviolet Grade Fused Silica: JGS1 (China), equivalent to Suprasil 1 and 2 (Heraeus), Spectrosil A and B (Saint-Gobain) and Corning 7940 (Corning), Dynasil 1100 and 4100 (Dynasil).

Optical Grade Fused Quartz: JGS2 (China), equivalent to Homosil 1, 2 & 3 (Heraeus), Dynasil 1000 & 4000 and 5000 & 6000 (Dynasil)

Full Spectrum Fused Silica: JGS3 (China), equivalent to Suprasil 300 (Heraeus). Different Properties Parameter Value Maximum Size Transmission Range(Medium transmission ratio) OH- Content Fluorescence (ex 254nm) JGS1 <Φ200mm> 0.17~2.10um (Tavg>90%) 1200 ppm Virtually Free JGS2 <Φ300mm> 0.26~2.10um (Tavg>85%) 150 ppm Strong v-b JGS3 <Φ200mm> 0.185~3.50um (Tavg>85%) 5 ppm Strong V-B Impurity Content Birefringence Constant Melting Method Applications 5 ppm 2-4 nm/cm Synthetic CVD 20-40 ppm 4-6 nm/cm Oxy-hydrogen melting 40-50 ppm 4-10 nm/cm Electrical melting Laser substrate: Window, Semiconductor and high IR & UV substrate lens, prism, mirror... temperature window

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Fused Silica, SiO2 Glass Properties

Fused silica is a noncrystalline (glass) form of silicon dioxide (quartz, sand). Typical of glasses, it lacks long range order in its atomic structure. It’s highly cross linked three dimensional structure gives rise to it’s high use temperature and low thermal expansion coefficient. .Key Fused Silica Properties Near zero thermal expansion Exceptionally good thermal shock resistance Very good chemical inertness Can be lapped and polished to fine finishes Low dielectric constant Low dielectric loss Good UV transparency . Typical Fused Silica Uses High temperature lamp envelopes Temperature insensitive optical component supports Lenses, mirrors in highly variable temperature regimes Microwave and millimeter wave components Aeronautical radar windows General Fused Silica Information High purity sand deposits provide the raw material for bulk refractory grade, which is electric arc melted at extremely high temperatures. Optical and general purpose fused silica rods and tubing are drawn from a melt made from high purity chemicals. Fiber optic purity is made by thermal decomposition of high purity gaseous silica containing chemicals. The glass may be clear or translucent, in which case it is often referred to as fused quartz. The glass has very high viscosity, and this property allows the glass to be formed, cooled and annealed without crystallizing. Fused silica glass is a very low thermal expansion material, and so is extremely thermal shock resistant. The material is also chemically inert up to moderate temperatures except to hydrofluoric acid, which dissolves silica. It will devitrify above about 1100°C in the presence of contaminants such as sodium, phosphorus and vanadium, with the formation of cristobalite crystals which destroy the properties of the glass. The dielectric properties are stable up through gigahertz frequencies. Download Fused Silica datasheet Fused Silica Engineering Properties*

Fused Silica Mechanical Density Porosity Color Flexural Strength Elastic Modulus Shear Modulus Bulk Modulus Poisson’s Ratio Compressive Strength Hardness Fracture Toughness KIC Maximum Use Temperature (no load) Thermal Thermal Conductivity Coefficient Expansion Specific Heat Electrical Dielectric Strength Dielectric Constant Dissipation Factor Loss Tangent Volume Resistivity of Thermal Units of Measure gm/cc (lb/ft3) % (%) — MPa (lb/in2x103) GPa (lb/in2x106) GPa (lb/in2x106) GPa (lb/in2x106) — MPa (lb/in2x103) Kg/mm2 MPa?m1/2 °C (°F) SI/Metric 2.2 0 clear — 73 31 41 0.17 1108 600 — 1100 (Imperial) (137.4) 0 — — (10.6) (4.5) (6) (0.17) (160.7) — — (2000) (9.6) (.31) (0.18) (750) (3.82) (0.00002) — — W/m?°K (BTU?in/ft2?hr?°F) 1.38 10–6/°C (10–6/°F) J/Kg?°K (Btu/lb?°F) ac-kv/mm (volts/mil) @ 1 MHz @ 1 MHz @ 1 MHz ohm?cm 0.55 740 30 3.82 0.00002 — >1010 *All properties are room temperature values except as noted. The data presented is typical of commercially available material and is offered for comparative purposes only. The information is not to be interpreted as absolute material properties nor does it constitute a representation or warranty for which we assume legal liability. User shall determine suitability of the material for the intended use and assumes all risk and liability whatsoever in connection therewith.