Oxidation of pure iron in superheated steam of 550 gr C and 1 atm. (ref 10)
SEM picture of pure iron specimen, exposed in superheated steam at 550 gr C during 53 days. (foto KEMA, ref 10).
Sem picture of detail of iron exposed in superheated steam at 550 gr C during 53 days. Direction of steam is top-down. Oxide at the top is red and at the bottom dark grey. (foto KEMA, ref 10).
Sem picture of detail of foto 3053. (foto KEMA, ref 10).
SEM picture of small hematite needles on the samples in superheated steel. This sample was pure orange coloured. Sometimes these small needles were found aside the larger plates. (foto KEMA, ref 10).
Transmission Electron Microscope picture of the needles, shown in Figure 3026. (foto KEMA, ref 10).
Sem picture of pure iron exposed in superheated steam at 550° C during 13 days. "Basalt" blocks are magnetite. (foto KEMA, ref 10).
Sem picture of border of grey to red oxide. Oxidation in superheated steam at 550 gd C during 13 days. (foto KEMA, ref 10).
Oxidation of pure iron in superheated steam at 450, 550 and 650 gd C and 1 atm. Addition of oxygen to the superheated steam did not result in higher oxidation rates. At 650 gd C, where the oxide wustiet FeO is stable the oxidation rate is mugh higer than at 450 and 550 gd C. (ref 10).
Cross sections of oxide scales formed at 550 °C in superheated steam. Picture a: after 11 days (oxygen in steam) no hematite; b: after 33 days (oxygen in steam) hematite present; C: after 31 days (no oxygen) no hemnatite. (foto KEMA, ref 10).
Cross sections of oxide scales formed at 450 and 12 days exposure (foto a), at 550 and 18 days exposure (foto b) and at 650 °C and 25 days exposure (foto c) in superheated steam with oxygen. (foto KEMA, ref 10).
SEM pictures (pictures a, b and c) of the oxide surface of specimen exposed to oxygen containing superheated steam at 550°C. Photo d: Transmission Electron Microscope Picture of thin plates in photo c. (foto KEMA, ref 10).
Optical microscope photo (interference contrast) of cross section of a specimen exposed in oxygen containing superheated steam of 650°C. Photo's a and b: large crystals in the wustite layer (FeO). Photo's c and d: hematite needles in the cracks. (foto KEMA, ref 10).
Phase stability diagram of the Fe_O system. (ref 10).
Cross sections of oxide scales formed at 650 (photo a) and at 550°C (photo b). Blisters in the FeO scale at the turning grooves (photo a). Pores in the magnetite scale at the tops of the turning grooves (photo b). (foto KEMA, ref 10).