To view the chemical impurities of various grade and type of quartz please click on this link. https://docs.google.com/spreadsheet/ccc?key=0AolHUVO7RVi_dFZVam1xWU10Mk1xVUFzN2lpUExiQkE

The table we compiled indicates the results of measurements performed by various analitical techniques and instruments. Spectrometrics analyses and atomic absorbsion measurements do provide reasonably reliable data regarding the purity of the material. However, because some of the methods are destructive, expensive and time consuming the manufacturers of the materials are performing these test periodicly on randomly selected batch of material only.

PERMEABILITY;

Quartz and Silica is impermeable for most gases, although Helium, Hydrogen and Deuteriumdoes diffuse at elevated temperatures and under special processes and conditions.

The permeability constant is estimated to be:

@600C/cc/sec/cm2/mm/cm/Hg

Helium=2.192 x 10-8

Deuterium=1.812 x 10-9

Hydrogen=2.110 x 10-9

CHEMICAL DURABILITY

Quartz and Silica have exceptional durability properties against most chemicals and exposure to these chemicals will not cause visible surface change or demage. Ther eare two exceptions:

1. HF 40% solution, etching rate= 13000 Angstro/min

2. NaOH 30% solution, etching rate=5.8 Angstrom/min

Others etching rate=<1.0 Angstrom/min

REACTIVITY TOWARD OTHER MATERIALS

1. Metals: Mg, Al = reaction @>600C, Si = low reaction

2. Gases: No reaction

3. Salts: BaC12 = some reaction, KF = strong reaction, KCL = rapid devitrification @ high temperatures

4. Oxides: CaO, CuO, Fe203 = reaction over >800C, PbO = strong reaction