| The aim of the study was to investigate the initial stage of the carburisation of nanocrystalline iron with methane at low temperature (500° C). The nanocrystalline iron samples contained small amounts of additives (Al2O3, K2O, CaO) applied as structural modifiers. The carburisation process was controlled by thermobalance - a differential reactor. After carburisation, the samples were characterised using XRD method and Mössbauer spectroscopy. The mass increase at the beginning of carburisation did not correspond to the determined iron carbide content. A formation of a thin carbon layer on the iron crystallite surface, accompanied by diffusion of iron atoms to this layer, was proposed for the initial stage of the process. |
full paper (pdf, 528 Kb)