Summary (by Thao)

Ikeda, Y; Nii, K Mechanism of Accelerated Oxidation of Fe--Cr Alloys in Water Vapour Containing Atmosphere,Trans. Natl. Res. Inst. Met. (Jpn.). Vol. 26, no. 1, pp. 52-62. Mar. 1984

Fe-Cr alloys with Cr concentration from 5-30% have been oxidized under dry and wet (10 vol%H2O) oxygen at 1023 and 1173 K during 5h, 25h and 75h to study the magnitude of oxidation rate and acceleration mechanism by water vapor.

Results from the experiments show that oxidation of Fe-Cr alloys under water vapor occurred vigorously than under dry oxygen condition (especially alloys with Cr percentage less than 15%). By using sulfur decoration method and SEM technique in studying the cracks and composition of oxide layers, authors found that Fe-Cr alloy with Cr percentage less than 20% developed two-layered scale (outer layer is Fe oxide. Inner layer is spinel type oxide of Fe and alloying elements.).The remarkably scale spalling of 304 SS was observed. Authors suggested that the penetration of oxidant gas through the scale/ alloy interface interfered (or prevented) the formation of Cr rich protective layer in water vapor containing atmosphere.