Effects of Fe and Si Additions on Erosion-Oxidation Behavior of Nickel Alloys in Chlorine-Containing Oxidative Atmospheres

High-temperature erosion-oxidation (e-o) of ni-20cr-(0-30)fe-(0-4)si was investigated in fluidized bed waste incineration conditions. the specimens were tested in a rig for 250 h, under the collision of hot silica sand contaminated with 0.5 wt.% of nacl-kcl salt mixture at a temperature of 700 °c. to have a better understanding of the materials’ behavior, the specimens were also oxidized at 560 °c for 100 h in the atmosphere of air + chlorine vapors. the thickness reduction and mass gain of the specimens were used to evaluate the materials under e-o and oxidation conditions, respectively. the specimens were studied using fesem, eds, and xrd analysis. at e-o conditions, ni-20cr showed the highest material loss (~17.6 μm). the addition of 30 wt.% of fe to the alloy decreased the wastage to about 6.7 μm. the e-o resistance of ni-20cr-30fe-4si was about two times lower than the si-free alloy which indicates that si had a detrimental effect on the e-o resistance of the alloys. under oxidation conditions, ni-20cr-30fe showed the highest resistance with a mass gain of about 0.1 mg/cm2. the addition of 4 wt.% si caused a dramatic decrease in the oxidation resistance of the alloy (mass gain of ~3.8 mg/cm2). the addition of fe stimulated cr2o3 scale formation by which the higher e-o and oxidation resistance of the alloy were confirmed. in ni-20cr, the formation of a multi-component scale, and in ni-20cr-30fe-4si, a porous surface scale formed through active oxidation were possibly responsible for the poor performance of these alloys.