Compression of Fe 3 C to 30 GPa at room temperature

Polycrystalline Fe3C (cementite) was compressed in a neon pressure medium to 30.5 GPa at 300 K using diamond-anvil cell techniques. Angular dispersive X-ray diffraction of Fe3C was measured using monochromatic synchrotron radiation and imaging plates. No phase transition was observed up to the highest pressure studied. The pressure–volume data were fitted to a third-order Birch–Murnaghan equation of state. With V 0 constrained to a measured value of 155.28 A3, the best fit yielded a 300-K isothermal bulk modulus K 0 = 174 ± 6 GPa, and its pressure derivative at constant temperature K 0 ′ =(K 0 /P) T = 4.8±0.8.