Influence of Exposure Pressure on Oxidation Behavior of the Ferritic-Martensitic Steel in Steam and Supercritical Water

摘要

Oxidation tests for ferritic-martensitic steel were conducted in steam and supercritical water under 0.1-25 MPa at 600 A degrees C. The oxidation kinetics in three different environments showed near parabolic behavior. The weight-gain data indicated a higher oxidation rate with increasing pressure. Samples exposed to higher steam pressure exhibited more pores and a greater amount of cracks in the outer oxide layer. Combining the SEM/EDS with XRD analysis, it was found that the oxide scale was a typical duplex structure. The outer layer contained Fe3O4 and Fe2O3, while the inner layer consisted of Cr-rich spinel. The mechanistic effect of pressure on oxidation rate was discussed.