Effect of Ru on corrosion resistance of high Cr content superalloy

Effects of Ru on the corrosion resistance of Ni‐base superalloys are still controversial. In the paper, the influence of Ru on the hot corrosion behaviour of Ni‐based superalloys containing a higher level of Cr was investigated. Results show that corrosion resistance of the superalloy with high Cr content is enhanced with the increase of Ru. The reason for this is that the addition of Ru increases the segregation degree of Cr and Mo in the interdendritic region and promotes the formation of a continuous Al2O3 and Cr2O3 layer adjacent to the superalloy. In the research, the addition of Ru was found to increase the average segregation coefficient of Ni and Al and decrease the average segregation coefficient of Cr in the Ni‐based superalloy containing a higher level of Cr. The addition of Ru significantly promoted the formation of a continuous alumina and Cr2O3 layer and enhanced hot corrosion resistance at 900 °C in mixed melt salt.