Ferromagnetic metals, carbon formation

The accumulation of carbon on metal surfaces when heated in the presence of carbon containing gases is a serious problem encountered in a number of commercial processes. Although carbon appears to deposit on most surfaces there are some materials which are more vulnerable than others since they contain constituents which catalyze carbon formation. The highest catalytic activity is exhibited by the ferromagnetic metals and in particular, iron. Furthermore it is well known that the surface state of such metals can have a dramatic effect on their ability to catalyze the formation of carbon. 

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