High Temperature Oxidation of Kanthal A1 Alumina Forming Alloy: Effect of Yttrium Ion Implantation on the Oxide Layer Properties

摘要

The effect of yttrium implantation on the oxidation behaviour of a commercial alumina forming FeCrAl alloy (Kanthal Al) has been investigated during isothermal exposures in air at 1173 K. The kinetic curve of the bare specimen exhibits an initial transient stage during the first 6 hours, followed by a parabolic regime. The scale growth kinetics of the yttrium-implanted alloy obeys a parabolic rate law with two subsequent stages with a much lower rate constant during the second stage. Kinetic results indicate that yttrium implantation significantly reduces the growth rate of the oxide scale. In situ X-ray diffraction reveals a marked influence of the reactive element on the composition of the oxide scale. Yttrium suppresses the formation of transition alumina and promotes the growth of α-Al{sub}2O{sub}3, thereby leading to the earlier formation of a protective oxide scale.