Fe3C has been successfully prepared though a sol-gel process, performing good magnetic properties, whose saturated magnetization can be adjusted by the heating temperature. The introduction of hexamethylenetetramine (HMTA) improves the interference from Fe and ferrite, realizing a flexible and high-efficient route to iron carbide by tertiary amine. We believe the carbon-capsulated Fe3C will be a potential candidate in magnetic materials. (C) 2015 Elsevier Ltd. All rights reserved.