On the breakaway oxidation of Fe9Cr1Mo steel in high pressure CO2

Modelling carburisation in 9Cr-1Mo ferritic steel tube substrates in experimental CO2 atmospheres

“…For example, in alloys P92 and VM12, the injection rates observed were approximately 2.8×10 -17 and 6.0×10 -17 kg m -2 s -1 respectively [26] under closer to plant conditions of 550°C and in a leaner carbon atmosphere of 50% CO2/Ar mixture. The work suggests that a constant injection rate is likely to be valid and in [34] it reveals that a constant carbon injection rate will in fact lead to carbon saturation faster than variable carbon injection rate with time.…”

“…Within the oxide, bright concentrations in the carbon map are most likely to be graphite depositions. In fact, electron diffraction studies [unpublished work] conducted on these deposits identified them to be pure graphite precipitations, results showing graphite in similar samples are presented in [34,35]. The maps reveal that the inner-scale has a complex structure, consisting of Fe, Cr and Si-rich oxides.…”

Effect of pressure and impurities on oxidation in supercritical CO2

“…Supercritical CO 2 (sCO 2 ) is being investigated as a working fluid for a range of power generation applications including nuclear, fossil, concentrating solar power (CSP), geothermal and waste‐heat recovery, due to its unique properties and relatively low critical point (31°C/7.4 MPa) . Several near‐term applications including waste‐heat recovery have modest temperatures of ≤550°C, similar to the temperatures in the UK advanced gas‐cooled reactors operated at 4.3 MPa (ie, subcritical) …”

“…Impurities could also assist in C permeating the protective surface oxide (either Cr 2 O 3 or Al 2 O 3 ). Whereas 9%Cr steels have shown severe internal carburization, higher alloyed materials at higher temperature have not shown much carbon ingress …”

Microstructural degradation of polycrystalline superalloys from oxidized carbides and implications on crack initiation

“…This experimental method has previously been applied to superalloys to study the accumulation of GND fields near grain boundaries and non-metallic inclusions [8,9]. APT analysis of oxide particles and oxide scales from superalloys, oxide dispersion-strengthened ferritic alloys and steels have been successfully characterised giving accurate chemical composition data [10][11][12][13][14][15].…”