Two products are formed in the process of carburization of iron with hydrocarbons: iron carbide (Fe3C, cementite) and in the next stage - carbon deposit. This paper deals with the formation of carbon deposit on nanocrystalline iron from ethylene decomposition and the reduction of its product with hydrogen.
The carburization process was controlled using spring thermobalance. The samples after carburization contained cementite and some amount of carbon deposit in the form of carbon nanofibers and carbon nanotubes. In the next step iron carbide had been reduced under hydrogen flow at 400 – 500°C and pure iron was obtained. Some carbon was hydrogenated and the morphology of the remaining carbon deposit was changed – thicker carbon nanofibers were eliminated and thinner carbon nanotubes remained.
The samples after carburization and reduction processes were characterized using XRD (X-rays Diffraction) and HRTEM (High Resolution Transmission Electron Microscopy) methods.