Abnormal oxidation behavior of Fe in Ti(C,N)-304ss cermet during early oxidation stage

摘要

In this work, the oxidation experiments of Ti(C,N)- 304 stainless steel (304ss) cermet were carried out at 650 degrees C in the air. Abnormal oxidation behavior of Fe in the Ti(C,N)- 304ss cermet was observed for the first time, and it was investigated by field emission scanning electron microscope (FESEM) and 3D laser scanning confocal microscope (LSCM). A gap was generated in the TiO2/304ss interface due to the volume shrinkage led by the oxidation of Ti(C,N). When the tip of the gap propagated to the Cr-depleted region in 304ss, Fe atoms in this area reacted with O atoms and formed iron-contain oxides. Cations (Fe3+ and Ti4+) in oxidation products interdiffused to each other and formed Fe2TiO5 in the gap at high temperature. The gap is a rapid diffusion path for atoms, and Fe atoms outward diffused along the gap to the oxidation surface and formed Fe2O3 covering the oxidation surface. (C) 2019 Elsevier B.V. All rights reserved.