Interface processes and anomalous oxygen transport in rapid metal oxidation and magnetite formation at protoplanetary conditions

It has long become evident that the stability and abundance of water across the solar protoplanetary disk was affected by extensive gradients of temperature and oxygen fugacity, but it is unclear to which extent water was directly involved in gas–solid interactions with minerals. In order to better understand the chemical and mineralogical record of water in the early stages of the solar system, I have studied the reaction of metallic Fe94Ni5Co1Cr1—an analog to common minerals in the protoplanetary disk—with gaseous H2/H2O mixtures at total pressures of 1 and 10 mbar and temperatures of 350, 450, and 600 °C. The experiments used a specifically designed gas-mixing furnace equipped with a controlled evaporator-mixer for precise H2O dosing. The interpretation of the reaction products is aided by nanoscale chemical and microstructural analysis using focused ion beam methods and transmission electron microscopy, providing quantitative measures of the reaction rates and insights into the reaction mechanisms. Th...