Microstructural Characterization of Reaction Products on Iron Based Alloys Exposed to H2/H2S Atmospheres at High Temperatures

Abstract

Thermogravimetric measurements in H2/H2S environments for up to five hours were carried out to determine the sulphidizing behavior of Fe-20Cr and Fe-20Cr-0.7Y alloys. These measurements helped to determine the mechanism of sulphidization in the early stages. The reaction products were characterized using a scanning electron microscope coupled to an energy dispersive analyzer and by X-ray diffraction analysis. The addition of yttrium influenced the morphology of the sulphide layer and the reaction kinetics

New method for the preparation of S doped Fe samples characterized by AES and TOF‐SIMS depth profiling

“…The method also offered the additional benefit of obtaining a pure binary Fe–S sample without any additional elements added to the Fe. According to the literature, Fe–S is normally prepared by allowing a mixture of H 2 S/H 2 to flow over a Fe substrate . This leads also to the doping of Fe with H, which has known side effects in Fe such as grain boundary embrittlement .…”

Influência de um revestimento de nióbio sobre a resistência à sulfetação das ligas FeCr e FeCrY

“…desvios de estequiometria, quando comparados com seus óxidos correspondentes12 . Isto mostra que esta camada é altamente defeituosa, produzindo produtos de reação com características não protetoras na superfície57 . A seguir, na TAB.3, estão apresentados valores comparativos de energia livre de formação de óxidos e de sulfetos, respectivamente, mostrando a diferença de estabilidade entre estes compostos.…”