- Production and characterization of bulk cementite
Cementite (Fe3C, theta phase) is one of the most important phases in steels, which plays a critical role in the mechanical properties of steels. It has been claimed to be metastable at all temperatures with respect to graphite and its saturated solution in iron. It has a complicated crystal structure (a=0.45248 nm, b=0.50896 nm and c=0.67443 nm), which can be understood as a regular stacking of a prism of Fe atoms containing a carbon atom in the center position. It is harder than ferrite and is quite brittle. However, detailed study in its properties was obstructed by the difficulty to produce bulk specimen of cementite. Most of the measurements up to date were performed in the cementite either extracted from cast iron or steels or cementite films (2.5-3.0 micrometer thick) produced by PVD method. Larger discrepancy exists therefore due to the large difference in the individual specimens.
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