Material Grades

In technical lamp applications the choice of the appropriate quartz glass grade is the key for high performance and high reliability of our customer's products.

Heraeus provides technical consulting to support our customers in finding the right materials for their new developments and strategic products. Especially the synthetic grades which aid our customers in developing leading UV applications.

Electrically fused quartz glass
Today the electrical fused process is the standard method used to produce quartz glass, notably in the shape of quartz glass tubes. The basic material is suitable for high working temperatures. The various quartz glass qualities differ in their residual trace element content and their added dopant.
With respect to sophisticated lamps, e.g. video projectors, quartz glass of very high chemical purity is needed. When doping with titanium, for instance, the transmission of the glass changes. This is relevant when the light of a lamp has to be screened in order to remove certain light lines for special applications.

Flame fused quartz glass
Fusing quartz glass in a oxygen/hydrogen flame (Verneuille-process) is the original method for quartz glass manufacture. The relatively high OH content in the tubes serves as good physical resistance against aggressive UV radiation. The tubes made in this way are characterised by low bubble content. Due to the mulit-stepped drawing method used to produce this material it has a nearly perfect shape.

Synthetic quartz glass
Synthetic quartz glass fabrication with silicon tetrachloride results in a glass quality of very high purity. For this reason, synthetic quartz glass is one of the purest materials worldwide. Synthetic quartz glass is nearly perfect: devoid of bubbles and extremely UV-radiation resistant. It has the highest UV transmission and thus is best specified for deep UV lamp materials.