Furnaces for CNT growth

 

Furnaces for CNT growth

The CVD reactor consist of a horizontal quartz tube housed in a cylindrical furnace 100 cm long, in which a constant nitrogen gas flow is mantained at pressures ranging from 1.5 to 2.0 bars. The temperature profiles in the reactive region of the quartz tube are monitored by a calibrated cromel / allumel industrial K-type thermocouple probe, inserted into the flow through the exit end of the tube.

Two different tubular furnaces are used to achieve the CVD process (Carbolite TZF1265C). One furnace, employed for preliminary tests, consists in a single thermostatic region long about 10cm, while the other one has a three-zone thermostatic system which allows to keep the deposition temperature stable and uniform along 25 cm, hence enabling the CNT growth over a larger surface.

These models utilise a resistance wire heating element wound around a ceramic worktube, forming an integral part of the heating element to ensure excellent thermal uniformity. The thermocouple is located in a protected position between the outside of the worktube and heating element, allowing the full worktube diameter to be used.