The effects of excimer laser annealing and yttria on corrosion of an FeCrNi alloy at 700°C

Abstract

AbstractSeveral surface and near‐surface analysis methods have been used to examine the effects of excimer (KrF, 248 nm) laser annealing and the addition of 2 wt.% Y2O3 on the early stages of corrosion of an Fe‐25Cr‐20Ni alloy at 700°C. Two specific questions were addressed experimentally: (1) Can excimer laser treatment improve the corrosion properties of the FeCrNi alloy in a mixed gas environment (containing oxygen and sulfur)?; (2) Does the Y2O3‐induced improvement of the corrosion behavior of the alloy result from prevention of S segregation to the surface or scale‐metal interface? Results show that laser annealing increased the Cr surface concentration of the treated alloy, but did not enhance the formation of a Cr‐rich oxide. However, the treated alloy was less susceptible to scale breakdown and sulfide formation. Surface segregation of S was not prevented by the Y2O3 addition. Differences between doped and undoped alloys may be attributable primarily to changes in microstructure.