HERAEUS MATERIALS

CFQ099

CFQ 099 is a basic purity grade of electrically fused quartz glass for industrial (non-semiconductor) applications.

CHEMICAL PURITY

Typical trace elements and OH content in quartz glass (ppm by weight oxide)

 
Elements Al Ca Cr Cu Fe K Li Mg Mn Na Ti Zr OH Content
CFQ099 15 0.8 n.s. <0.05 <0.1 0.4 0.8 1.2 0.1 0.1 0.9 0.8 n.s.*
* Not specified - will be treated on customer request

General Product Description

The electrical fusion process uses resistance heating to melt highly refined quartz sand into semifinished quartz glass products. Electrically fused quartz glass is characterized by:

• High purity level
• Low bubble content
• High homogeneity
• Excellent thermal shock resistance
• High visible and IR transmission

The main attributes of electrically fused materials are the low OH (hydroxyl) content and reduced devitrification rates. The low hydroxyl content increases infrared transparency and viscosity. The higher viscosity results in an increased maximum use temperature as well as helping to inhibit devitrification. In addition to the higher viscosity, devitrification is also restrained by the neutral/reducing atmosphere used during melting. This causes the material to be slightly oxygen deficient which has an inhibiting effect on devitrification. The OH content of HSQ 100, HSQ 300 and HSQ 700 is below 30 ppm. This can be further reduced to below 5 ppm via heat treatment under the right conditions. Electric fusion is the most commonly used melting process for manufacturing quartz glass. There are two methods of electric fusion: continuous and batch (boule) fusion.