For starting material which consists solely of carbon atoms and is very clean with minor impurities, a graphite furnace of the LHTG range or the HTK range up to 3,000 °C is suitable. Both, heating elements and insulation of the cold wall furnaces consist of high quality graphite materials. The top loader furnace LHTG is fitted with a circular mantle heater in a perfectly symmetrical meander. In the front loader chamber furnace HTK GR the sample is heated symmetrically from four sides.
If organic matter of unknown composition, or containing a large amount of impurities is used for graphitization, it is recommended to purify the sample by pre-carbonization under inert gas atmosphere before heat treatment in a more sensitive high temperature graphite furnace. This can be done in a low temperature hot wall furnace of the GLO range up to 1,100 °C. For samples consisting of carbon atoms with only little impurities Carbolite Gero offers specialized HTK graphite furnaces with dedicated debinding equipment, where carbonization and graphitization are carried out in one heat treatment step. Those furnaces are equipped with a retort and an intelligent gas guidance system which assures that the impurities are safely discharged from the furnace into the afterburner.
Carbolite Gero produces a wide range of heat treatment equipment and high temperature systems from 30–3,000 °C. Heat treatment with Carbolite Gero furnaces is carried out under vacuum, partial pressure and overpressure. Gases to be used include inert gas such as nitrogen or argon as well as reactive gases like oxygen and hydrogen. The product range comprises laboratory-scale systems for research and development but also large-scale production plants.
(Source: Carbolite Gero GmbH & Co. KG)