Fused Silica Powder

SiO2, Amorphous



Properties and production of fused silica 

Fused silica is an amorphous, high-purity form of silica, typically between 99.4% and 99.9% pure. It is an exceptionally hard and thermally stable glass distinguished by its very low coefficient of thermal expansion, which gives it high resistance to thermal shock. It can be produced by melting purified quartz crystals or high-purity silica sand using several methods: Electric arc fusion, Carbon electrode fusion, Plasma arc fusion or Continuous extrusion with gas-fired furnaces.


Applications in various industries 

Electronics: 

·        It is a primary material in the electronics industry, approximately 70% of its market.

·        Its excellent dielectric and insulating properties are essential for semiconductor manufacturing. 

Investment casting: 

·        Fused silica is a key refractory material in investment casting.  In this process, it is used to create a slurry  that coats a wax replica of a component.  The resulting ceramic shell is heated, and once the molten metal is poured, the shell can be easily knocked away. Compared to other refractories like zirconia and aluminosilicates, fused silica allows for easier "knockout" and a cleaner casting surface. Its low thermal expansion provides excellent dimensional stability during the process. 



High-temperature and optical uses: 

·        Refractory material: Used in crucibles and other high-temperature applications.

·        Optical components: Its exceptional optical transmission properties in both UV and infrared make it ideal for lenses, windows, and prisms in specialized applications, including high-power lasers.

·        Chemical processing: It is resistant to most chemical attacks (with the notable exception of hydrofluoric acid). 


Chemical Properties :

        Formula:                                SiO2

Formula Weight:                  60.09

CAS Number:                       7631-86-9

EINECS:                                 231-545-4

        Melting Point:                       1710oC

        Boiling Point:                        2230oC

        Density:                                 2.2 – 2.6 gm/cm3

Form:                                     Powder, Fused, Amorphous

Particle Size:                        -325 mesh (< 45 microns)

        BET:                                        5 m2/gm


Safety Data Sheet (pdf)