Abstract
We have investigated the stability of Fe3C-cementite at high pressure and high temperature, because there has been a little knowledge about that. In the 2007 annual meeting, we reported a preliminary result that Fe3C may be transformed into Fe7C3 + Fe at high pressure and high temperature. However, it was strange that we observed not Fe but FeO in the run products. We used NaCl as thermal insulating material in a diamond anvil cell (DAC). Since it is known that NaCl often adsorb H2O, it may cause the oxidation of Fe. Therefore, we used different thermal insulating materials (Al2O3 and CaSiO3) in order to see some effects of those thermal insulators.
