Corrosion by Hot CO₂ Gases

Abstract

Heat-resisting alloys are designed to survive high-temperature oxidation by forming a slow-growing scale, usually Cr2O3, which acts as a barrier between the metal and its environment. However, alloys that succeed in this way when exposed to hot oxygen or air fail to do so in CO2 gas. Instead, they exhibit rapid “breakaway” corrosion, developing oxides of alloy base metal iron and/or nickel. The growth of these non-protective scales is accompanied by internal carburization of the underlying alloy. Carbon passes through the oxide, dissolves in the alloy, and precipitates chromium as carbide. Removal of chromium from its matrix makes the alloy incapable of reforming chromia, and recovery from breakaway becomes impossible.

Corrosion behavior of nickel-base alloys in high-temperature gas environments for ccs technologies

“…This can lead to pitting corrosion, see Figure 4. The ability of the material to form protective layers in a high temperature CO2 environment is also related to the minimum chromium content, which is reported to be approximately 16 wt% [10,11].…”