About Qsil Quartz Glass Netherlands

Qsil Fused Quartz Netherlands

Qsil is a leading producer of fused quartz products (formerly Philips Quartz Glass Factory from 1982-2016). In 2016, Philips sold their Quartz Glass Factory to another leading Quartz producer QSIL GmbH. Its products are widely supplied throughout the global market from the factories in Germany and Netherlands. The sole focus of Qsil is the manufacture of fused quartz (quartz glass). This covers the raw material treatment, the fusion of heavy wall cylinders, the manufacturing of small and large diameter tubes, and the fabrication of customized products.

With many years' experience in the melting and fabrication of fused quartz (quartz glass), as well as having state of the art processing technologies and quality control equipment, Qsil has unique capabilities to supply our customers with products of the highest quality. As a result, QSIL materials have been certified by leading OEMs.

Our worldwide customer base relies on the quality and performance they receive from Qsil's products. Qsil's main objective is to supply products which bring the highest level of value to our customers.

UV Quartz Sleeves are available in ready stock for all UV lamps. UV Quartz Sleeves available In most Diameters and Lengths. Customised UV Quartz Sleeves available.

UV Quartz Sleeves help from a safety perspective as UV lamps contain mercury. Quartz Sleeve is a product used over the UV lamp to protect the UV lamp from breaking. Good quality Quartz (such as Qsil Netherlands) is the only substance which allows 92% of the UV-C to get transmitted. Any other substance is a UV-block (borosilicate glass, normal glass, plastic, teflon etc).

Learn more about Qsil UVC Quartz Glass and UVC Special Glass and its uses in UV Quartz Sleeves, UV Quartz Glass, Protection Sleeves for UV-C Disinfection Lamps, UV-block Sleeves, Water-purification Sleeves etc by visiting this page.

Learn more about Qsil PH (Product range used in UV Quartz Sleeves, UV Quartz Glass, Protection Sleeves for UV-C Disinfection Lamps, UV-block Sleeves, Water-purification Sleeves etc.) by visiting this page.

Learn more about ilmasil® fused quartz by visiting this page.

Ved Group is the Exclusive Authorized Agent/Distributor/Partner/Representative in India for Qsil Fused Quartz Netherlands.

Reasons to Use Fused Quartz (Quartz Glass)

  1. High chemical purity and resistance
  2. High softening temperature and thermal resistance 
  3. High thermal shock resistance and low thermal expansion
  4. High transparency from the ultraviolet to the infrared spectral range

About Fused Quartz (Quartz Glass)

Fused quartz is an extraordinary material for numerous industrial applications. The single-component glass consists solely of silica (SiO2). Through its unique combination of thermal, mechanical and optical properties, fused quartz is one of the most important materials for industry and research. For the Semiconductor an Solar industries, fused quartz is used in high temperature processes because of its high softening point, low thermal expansion and excellent thermal shock resistance. It can withstand temperatures up to 1300°C and can be rapidly heated and cooled with virtually no risk of breakage. Because of its high purity, parts and systems made of fused quartz are ideal suited for industry equipment. For the Lighting industry, fused quartz is an indispensable material due to the high optical transmission from ultraviolet through the infrared light.    For the Chemical industry and for laboratory equipmentation, fused quartz is used because of its resistance to acids, bases and water. With the exception of hydrofluoric acid, phosphoric acid, and alkaline compounds its properties are unaffected.For the Electronics industry, fused quartz is characterized by high dielectric strength, low electrical conductivity and superior microwave transmission even at high temperatures.


  • Quartz Rods and Quartz Handles
  • Quartz Tubes for UV Lamps and UVC Lamps
  • Quartz Sleeves for UV Lamps and UVC Lamps
  • Quartz Sleeves for UV Water Disinfection
  • Quartz Sleeves for UV Air Disinfection
  • Quartz Sleeves for HVAC Air Conditioning Duct UV Lamps
  • Special Quartz Glass for Automotive Lamps Manufacturing
  • Special Quartz Glass for UV Lamp Manufacturing
  • Amber Glass
  • Quartz Billets

Properties of Fused Quartz (Quartz Glass)

  • Transmission

Critical to the efficient transmission of light, clear fused quartz contains very low levels of impurities (as measured in parts per million). This single component glass is further distinguished from other glass material by a very high transmission of ultra violet light. The higher the purity of the material, the higher the transmittance in UV-range. For this reason, synthetically manufactured fused quartz materials show the highest transmission for ultraviolet light.


The UV transmission properties of fused quartz can be modified by the incorporation of a dopant in the material.  The doping causes the material to absorb a certain range of wavelengths. 


Hydroxyl (OH- ) groups in the material may cause absorption bands in infrared range.  The strongest of these bands, at 2,73 μm is used to determinate the OH-content in fused quartz materials. The higher the OH-content, the higher the absorption at this wavelength.


The light transmission of fused quartz may be reduced or even extinguished when the material is exposed to high-energy UV-radiation, X-rays, gamma rays and particle bombardment.

  • Mechanical/Electrical Properties
Mechanical Properties (at 20°C)

Mechanical property measurements are dependent upon geometry, thermal gradient and surface quality. For proper strength calculations, the lower pressure variable should be used.

Density 2,20 g/cm3 Bending Strength 68 N/mm2
Compressive Strength 1150 N/mm2 Elasticity modulus 7,5x104 N/mm2
Tensile Strength 50 N/mm2 Mohs Hardness 5,5-6,5


Electrical Properties

Dielectric loss factor
(at a frequency of 7,5 GHz)
tg δ ≈ 5 x 10-4
Dielectric constant ε ≈ 3,7 
(at 20 °C / 7,5 GHz)
Dielectric strength
at 20°C
at 500°C


250 - 400 kV / cm
  40 -  50 kV / cm

Specific electrical resistance 
at different temperatures:
at 20°C       1018 Ωm
at 100°C       1016 Ωm
at 200°C    4x1013 Ωm
at 400°C        1010 Ωm
at 800°C   6,3x106 Ωm
at 1000°C          106 Ωm
at 1200°C   1,3x106 Ωm


  • Chemical/Thermal Properties
Chemical Properties

Hydrolytic resistance per DIN 12111 ( 1.class)
Acid resistance per DIN 12116 ( 1.class)
Alkaline resistance per DIN 52322 ( 1.class)

Thermal Properties

ilmasil® PN

ilmasil® PI


ilmasil® PO 1 /
PO 2

ilmasil® PQ

ilmasil® PN 235

ilmasil® PN 350

ilmasil® PS

ilmasil® PE

Softening Point
lg h (in dPas)=7.6










Annealing Point
lg h (in dPas)=13




1159°C /






Strain Point 
lg h (in Pas)=14.5




1043°C /






Transformation Range 1075 - 1210°C
Processing Range
at lg h (in dPas) = 5 - 8  

Max. Usable Temperature

long term
short term



Coefficient of Thermal Expansion
  ca. 5,5 x 10-7 / °C
  • Other Properties

Devitrification is dependent upon surface cleanliness, atmospheric conditions and temperature cycling. Below 1025°C devitrification takes place very slowly, but above 1425°C devitrification is rapid. If heating cycles take the product above 1025°C , devitrification will be minimized if a minimum temperature of 250°C is maintained.

< 2,5 µl gas/g under vacuum at 1000°C.

OH-content determination of fused quartz glass
Basis for the determination is the OH- absorption band at 2,73 µm. A sample is tested by Infrared -spectrometer in the range of 2,5 - 3 µm.
COH = 0,1 x log (I0 / I) x 1/d x 104 COH OH-content in ppm
  I0 Basic Intensity at 2,73 µm
  I Intensity of maximum absorption
  d sample thickness in mm
    Coefficient of extinction: 77,5 l / Mol cm


Handling - Cleaning - Storage of Fused Quartz (Quartz Glass)

Fused quartz requires care in handling and use to achieve good performance. Cleanliness will help reduce devitrification and maximize the life of this material. Handle fused quartz with care and only with clean cotton gloves to avoid contamination . Wrap and store quartz in a clean, dry environment

Cleaning recommendation:

1. Cleaning with non-alkali cleaning agent and/or isopropyl alcohol.

2. Rinse with deionized (distilled) water

3. Air dry in clean environment and clean wrapping