Аннотация:The important problem of the joint entry of hydrogen and carbon into metallic iron at high and ultrahigh pressures remains debatable. This paper presents the first results of experiments on the interaction of cementite Fe3C with hydrogen in sealed platinum ampoules and in open sapphire ampoules at a pressure
of 30-100 MPa, created by pure H2. A comparative analysis of the experimental results showed that at hydrogen pressures (30-100 MPa) and high temperatures (1000–1150 oC), iron carbide actively interacts with hydrogen and almost completely decomposes to form iron and a fluid of the composition H2+CH4. The mass balance method in all experiments determined the concentration of volatile (H2+CH4) dissolved in quenching samples equal to ~ 0.70 wt. % (the average value of 4 measurements). The presence of H2 in
quenching iron samples is qualitatively confirmed on the basis of the results of Raman spectroscopy,according to which weak lines of hydrogen valence oscillation are observed in the high - frequency region (4000-4250 cm-1) of the Raman spectrum, which suggests an insignificant amount of H2 in the sample.
Gas chromatography was used to determine the composition of the fluid phase formed in experiments on the interaction of iron carbide (Fe3C) with hydrogen at high pressures.