The influence of silicon and yttrium on isothermal scaling of an austenitic Fe‐Cr‐Ni alloy (IN 519) at 1000 °C

Abstract

Abstract When present in austenitic Fe‐Cr‐Ni alloys, both silicon and yttrium influence scaling behaviour during oxidation tests in air at high temperatures. The former promotes the formation and maintenance of a continuous Cr 2 O 3 scale and the latter improves scale adhesion. During the isothermal exposure of nominally Fe + 24%Cr + 24%Ni east alloys at 1000°C a silicon content above 0.8% reduces the rate of scaling by providing additional sites for the lateral growth of the Cr 2 O 3 layer. Yttrium gives rise to the formation of Fe 9 Y particles which disrupt the continuity of the Cr 2 O 3 scale. The beneficial influence of silicon dominates the potentially detrimental effect of yttrium in alloys containing both silicon and yttrium.