330Cb alloy (Fe-35Ni-18Cr-1Nb-2Si) oxidation study between 800 and 1000℃

摘要

The 330Cb alloy (Fe-35Ni-18Cr-1Nb-2Si) has been oxidized, in air, in the 800-1000℃ temperature range. Results show the formation of a chromia layer acting as a good diffusion barrier under isothermal conditions. Nevertheless, some oxide scale spallation is generally observed after cooling to room temperature. A fine and adherent chromia scale is only obtained after short-term oxidation at 800℃. In this case, the scale is probably too fine to expect a protection against carburization. At 900℃ we have observed that the scale spalled off on the niobium rich alloy areas. At 1000℃ the scale adherence is very bad. This study shows that the oxide scale adherence is decreased when the 330Cb alloy oxidation duration is increased.