Skip to main content

Fused silica—fillers with extremely low thermal expansion


Fused silica is made synthetically in an electric arcing process at about 2000°C as an amorphous modification of quartz. It has a series of properties that are not united as completely at the same time in any other material. The most outstanding of these is its extremely low thermal coefficient of expansion (0,5*10-6/K), excellent elasticity and thermal shock resistance. The properties are complemented by a high transformation temperature, high softening temperature, low thermal conductivity, good optical transmissivity, corrosion resistance and a diffusion blocking effect against most substances. Through non-ferrous milling and downline screening processes we are also in a position of being able to produce fused silica granulations in the 1 µm range.


  • hardness of 6.5 (Mohs)
  • density of 2.2 g/cm3
  • chemically inert
  • extremely low coefficient of expansion of 0.5*10-6 K-1 (at a temp. of 20–300°C)

Main applications

  • electrical insulation
  • casting resin systems
  • electronics
  • precision casting
  • technical ceramics

That makes our fused silica an exceptionally high-grade filler from which you should also benefit. Speak to us about it!