Application of graphite in the industrial equipment used for various high-temperature
chemical-technological processes, restrains because of created by it impurities
background polluting final production.
Such problems, for example, exist in manufacture of semi-conductor monocrystals
(arsenide of gallium, silicon, germanium), monocrystals sapphire, a ruby,
etc.
The new constructional materials developed by us on the basis of graphite
with protective coatings will help with the decision of these problems.
The carried out industrial tests have shown, that application of graphite
thermal unit with a protective tungstin coating of all of its parts at melt
growth monocrystals of arsenide of gallium (MAG) allows to lower imuprity
background in the MAG (in comparison with the MAG, brought up in thermal unit
without a coating) on carbon, iron, cobalt, copper, chromium, to silicon approximately
twice (thus tungsten as an impurity in the MAG is not found out), and also
to increase electrophysical characteristics the MAG and a resource of work
of thermal unit.
It is possible to deposit W, Mo, Ta, BN and other high-temperature materials
as a coatings by thicknesse 0,1-1 mm onto shaped workpieces.
BASIC PERFORMANCE CHARACTERISTICS
Substrate Size, mm to 400x400x600
The density W, g/cm3 19,2 - 19,25
The impurities contents (total) in W , % wt 10-3 - 10-4
The thicknesse of coatings, mkm 30 - 100