Quartz / fused silica characteristics

Quartz (SiO2) is a natural material which is possible to recreate industrially.

Characteristics chart of Quartz / Fused silica : JGS1/ JGS2/ JGS3

Specific characteristic Comments
Chemical stability Very good (except with Fluorhydric acid)
Electric insulation Very good
Fusion temperature Fusion point at 1650°C
Thermal resistance Very good (0.5×10-6 /K)
Optical characteristics for natural quartz transmission from visible to 4µm. Quartz can also be opaque
Optical characteristics for fused silica Good transmission possible from UV (170nm) to NIR (3 µm)
Machining Relatively good compared to other glass products. Quartz can be molded, drilled, grinded, turned, polished, milled, welded or extruded (fiber optics)

Characteristics chart of Quartz / Fused silica : JGS1/ JGS2/ JGS3

Specific characteristic Comments
Chemical stability Very good (except with Fluorhydric acid)
Electric insulation Very good
Fusion temperature Fusion point at 1650°C
Thermal resistance Very good (0.5×10-6 /K)
Optical characteristics for natural quartz transmission from visible to 4µm. Quartz can also be opaque
Optical characteristics for fused silica Good transmission possible from UV (170nm) to NIR (3 µm)
Machining Relatively good compared to other glass products. Quartz can be molded, drilled, grinded, turned, polished, milled, welded or extruded (fiber optics)

Quartz tubes, quartz crucibles and quartz discs applications

Following above characteristics, Quartz have numerous industrial applications :

– Quartz windows are used to look into processing equipment, providing good protection against temperature and chemicals while keeping a good optical transparency.

– Quartz crucible, transparent or opaque are used as a recipient for processing materials at high temperature.

– Quartz tubing are popular choice for Laboratory equipment and chemical processing plants.

 

Machining quartz

Quartz is a material that can be machined, blew or welded. It is usually easier to process than soda-lime glass or even borosilicate. Custom shapes can be made according to customer requirements, from simple quartz plates to more complicated welded assemblies. Finishing is usually done by grinding, fire polishing or even mechanical polishing.

 

Utilisation du quartz en optique.

Quartz have interesting optical properties with a wide spectrum of transmission from UV to mid-IR while being fully transparent in the visible range. Optical fused silica material is common and its price is very competitive compare to many other optical materials.

 

Quartz in China

On top of the imported quartz brands (Corning 7980, Nikon NIFS, Heraeus Suprasil), there are 4 principal quartz quality :

– Quartz for industrial non optical usage with no specific denomination, usually produced locally.

– Three Fused Silica grades JGS1 / JGS2 / JGS3 for optical applications :

Comparison chart of Chinese fused silica

Parameters / Values
JGS1
JGS2
JGS3
Transmission (more than 80%) 170nm to 2.1 µm 260nm to 2.5 µm 190nm to 3.2 µm
OH- concentration 1.2% 150 ppm 5ppm
Remarks Less material impurities, higher price Few material impurities, competitive pricing Lot of material impurities, usage not recommended
Density
2.2 g/cm3
ABBE constant (V)
67.6
Refractive index (nd) @588nm @588nm
1.4586
Material Hardness
5.5-6.5 MOHS
Poisson Constant
0.2

In China there is numerous Quartz suppliers with unequal level of quality of raw material and processing. Stability in time and repeatability are problematic due to high turnover of qualified professionals. It is therefore necessary to have a close local follow-up of suppliers coupled with a panel of potential replacement suppliers to avoid procurement issues. Sinoptix is the ideal partner to guaranty quality stability of your quartz components from China.