This paper focuses on the effect of tungsten addition on the steam oxidation behavior of the Fe–20Cr–35Ni (atÿ) alloy at 1073 K. Steam oxidation
tests of the W added Fe–20Cr–35Ni (atÿ) alloy were carried out at 1073 K in an Ar–15ÿH2O gas mixture for up to 604.8 ks. The oxidation resistance of
the alloys was improved by adding W into the alloy. There are two effects of W on the steam oxidation behavior: the effect of solid solution and the effect
of precipitation. Tungsten in the alloy is enriched as a Ni–W alloy in the matrix of the internal oxidation zone (IOZ) during oxidation. The Ni–W alloy in the
IOZ may act as a diffusion barrier for oxygen and promote a continuous Cr2O3 layer. On the other hand, Fe2W precipitated in the alloy decomposes
during oxidation and provides alloying elements for forming FeCr2O4 and CrWO4 in the IOZ, resulting in a continuous Cr2O3 layer formation.