General Properties of Fused Quartz Glass

Fused quartz glass is practically single component glass consisting of SiO2. Silicon dioxide is in amorphous form and the temperature drop does not crack it, like f.g. crystalline quartz.

Fused quartz glass has a unique combination of physical and chemical properties: high optical homogeneity, small light absorption ( usual window glass absorbs the same quantity of light as quartz glass with the thickness of 100 m), resistance to the ionizing radiation and high intensity laser radiation, low coefficient of temperature expansion. All fused quartz glass products are thermally and chemically inert, the action of organic and inorganic acids except for hydrofluoric and phosphoric acid (heat to more than 300°C) do not affect them.

Almost all analytical solutions and precipitates are interacted chemically with fused quartz glass that is why platinum chemical ware can be successfully replaced by fused quartz glass chemical ware. Fused quartz glass products can be subjected under high temperature and pressure conditions (operating temperature 1250°C),dynamic and vibrating loads, kinetic heating and shock cooling, nucleus space radiation.

Fused quartz glass products are widely used in the following industries: atomic power, chemical machine manufacture, radio electronics, aircraft and space machinery, metallurgy, lighting, precision instrument making and many others.

1. Thermal properties:

   1.1 Coefficient of linear expansion α average for interval 293-1273 K.

   temperature, К (оС)	α*107, К-1	temperature, К (оС)	α*107, К-1	temperature, К (оС)	α*107, К-1
   213 (-60)	2.0	573 (300)	5.9	873 (600)	5.6
   323 (50)	4.0	623 (350)	5.8	923 (650)	5.5
   373 (100)	5.0	673 (400)	5.8	973 (700)	5.4
   423 (150)	5.5	723 (450)	5.8	1023 (750)	5.3
   473 (200)	5.6	773 (500)	5.7	1073 (800)	5.2
   523 (250)	5.7	823 (550)	5.7

   1.2 Annealing point

   Glass type	Annealing temperature, К (оС)
   	lower (corresponds to viscosity 1013,5 Pa·s)	upper (corresponds to viscosity 1012 Pa·s)
   КВ	1363 (1090)	1453 (1180)
   КУ-2	1343 (1070)	1443 (1170)

   1.3 Temperature of deformation (corresponds to viscosity 10¹⁰Pa·s)

   quartz glass type	deformation point, К (оС)
   KV	1613 (1340)
   KU-2	1603 (1330)

   1.4 Soft point (corresponds to viscosity 10^6,6 Па·с)

   quartz glass type	soft temperature, К (оС)
   KV	1973 (1700)
   KU-2	1993 (1720)

2. Electric properties

   2.1 Electric resistance

   at 293 К (20^оС) — higher 1·10²⁰ Ом·м;

   at 773 К (500^оС)- 7·10⁹ Ом·м;

   2.2 Dielectric constant e at frequency of 9,5·10⁹ Hz

   at 293 К (20^оС) — 3,8;

   at 1273 К (1000^оС) — 4,0;

   2.3 Dielectric strength;

   at 293 К (20^оС) — more than 3,5·10⁴ кВ/м;

3. Mechanical properties

   3.1 Bending strength s, MPa:

   at 293 К (20^оС) — not less than 39,2;

   at 1073 К (1000^оС) — not less than 68,7;

   3.2 Ultimate strength s, MPa:

   at compression — 588,6;

   at shock bending — 0,196-0,294;

   3.3 Young’s modulus

   Е — 73,6 GPa.

   3.4 Density

   at 293 К (20^оС)-2,21·10³ kg/m³

   3.5 Bruster’s coefficient

   in visible spectrum part — (3,5-3,7)^-12 m²/N