Role of Rare Earth Additions in the Phenomenon of Hot Corrosion

摘要

The severity of attack in the hot corrosion of nickel-base superalloys is greatly reduced in alloys containing a dispersoid of CeO2 or La2O3. These oxides interact with the sulfur entering the alloy from Na2SO4 decomposition, by forming an oxysulfide of the type M2O2S. In this way less Ni3S2 is formed, and hence less catastrophic oxidation. (Author)