Influence of the mode of introduction of a reactive element on the high temperature oxidation behavior of an alumina‐forming alloy. Part II: Cyclic oxidation tests

Abstract

Several routes of yttrium introduction were applied to test the high temperature oxidation performance of a FeCrAl alloy. Isothermal oxidation tests were described in a previous paper (Part I of this paper in this journal, 2004, 55, 352). Cyclic oxidation tests were performed in air under atmospheric pressure on blank specimens, Y2O3 sol‐gel coated‐, Y2O3 metal‐organic chemical vapor deposited (MOCVD)‐, yttrium ion implanted‐alloys, as well as on a steel containing 0.1 wt. % of yttrium as an alloying element. For the 20 hours cycles, all the samples, except FeCrAl‐0.1Y, exhibit weight losses after a few cycles, indicating drastic spallation of the oxide scales. The MOCVD coated specimen has the highest weight loss. The oxidation kinetics of the FeCrAl‐0.1Y alloy obey a parabolic law, indicating that the alumina scale formed on its surface is protective even after more than 1200 hours of oxidation (> 50 cycles). The 100 hours cycle oxidation tests give similar results. The FeCrAl‐0.1Y alloy exhibits the best oxidation behavior with very little spallation after more than 2000 hours (85 days) of oxidation at 1100°C (20 cycles). Most of the other samples exhibit severe oxide scale spallation followed by an increase of their oxidation rate related to the formation of non‐protective iron oxides.

Water vapor effect on high-temperature oxidation behavior of Fe3Al intermetallics

“…This is particularly true for reactive-element addition, whose effect on the high-temperature corrosion of alumina-forming materials was largely studied [16][17][18][19][20][21][22][23][24][25][26][27].…”

Influence of the mode of introduction of a reactive element on the high temperature oxidation behavior of an alumina-forming alloy. Part III: The use of two stage oxidation experiments and in situ X-ray diffraction to understand the oxidation mechanisms

“…5 shows that YAlO 3 and Y 3 Al 5 O 12 form simultaneously. After 48 h YAlO 3 is totally transformed into Y 3 Al 5 O 12 according to equation (2). The oxygen isotope distribution determined by SNMS (Fig.…”

“…Two previous studies showed that the introduction of yttrium, as an oxide or as implanted ions, into the surface of a model Fe-20Cr-5Al steel did not improve the high temperature oxidation rate, nor the alumina scale adherence [1,2]. The oxidation behaviour of the so-treated alloys was compared to the oxidation behaviour of the bare steel.…”

High temperature alloy chloridation at 850°C. Part I: Comparison of Ni‐based and Fe‐based alloy behaviour

“…Polished-cross sections were prepared and observed by optical microscopy in order to estimate the metal consumption. Samples were weighed before and after exposure to Ar/Cl 2 atmosphere; gross and net weight gains were collected in order to verify the adherence of the corrosion products to the underlying substrates [37]. The gross weight corresponds to the weight of the corroded samples together with the alumina crucible (and the spalled particles) minus the original weight of the crucible.…”