H. Buscail et al., THE INFLUENCE OF YTTRIUM IMPLANTATION ON THE OXIDATION OF IMPURE IRON-CONTAINING C AND MN AT 700-DEGREES-C, Oxidation of metals, 49(5-6), 1998, pp. 561-581
A study of impurity-yttrium interactions has been performed during iro
n oxidation [p(O-2) = 0.04 Pa, T = 700 degrees C]. Yttrium-implanted s
pecimens always exhibit better oxidation behavior compared with blank
specimens. On pure iron or the Fe 0.054 wt.%C alloy the beneficial eff
ect is attributed to Fe2YO4 formation. With the manganese-containing a
llays (Fe 0.2 wt.%Mn), the protective effect of yttrium is attributed
to YMnO3 formation. The best oxidation behavior is obtained with impla
nted Fe0.18 wt.%Mn-0.041 wt.%C alloys due to the formation of an YMnO3
oxide subscale at the scale-alloy interface. Yttrium implantation als
o hinders carbon segregation at the oxide-alloy interface. This effect
ensures better scale adherence. With the most-impure alloy, yttrium i
mplantation also changes the growth process from external cation diffu
sion to predominant inward-oxygen diffusion.