bhadeshia123 | Oxidation/carburisation of Fe-9Cr-1Mo in carbon dioxide, Roger Reed, Lecture 24 of 25 @bhadeshia123 | Uploaded December 2021 | Updated October 2024, 5 hours ago.
Lecture 24, by Professor Roger Reed, University of Oxford, in the series "Steel Research: A global journey", organised by Adreil Wong, Dominik Dziedzic and Steve Ooi to mark the retirement of Harry Bhadeshia.

Numerical modelling of the degradation of P92 martensitic steels in gas 70% CO2-30%H2O at 550 C is described, emphasising the formation of duplex oxide scale and internal carburisation. Numerical models with varying levels of sophistication are presented for the evolution of multiphase regions, subject to a Robin-type boundary condition representing a Boudouard surface reaction. The surface reaction kinetics at the spinel/substrate interface and the carbon transport kinetics in the substrate result in unusual carbon concentration profiles, measured here by glow-discharge optical emission spectroscopy (GDOES). Analysis of experimental data indicates that moisture decreases the rate of the surface reaction, despite higher carbon activity of the gas.

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