The combined effect of refractory coatings containing reactive elements on high temperature oxidation behavior of chromia-forming alloys

Abstract The high temperature oxidation behaviors of chromia-forming alloys (F17Ti and Fe–30Cr alloys) have been studied at 1273 K under isothermal conditions and at 1223 K under cyclic conditions, in air under the atmospheric pressure. To extend the oxidation lifetime, coatings have been applied onto the alloy surfaces. Al2O3 and Cr2O3 films doped with Sm2O3 or Nd2O3 were prepared via the metal-organic chemical vapor deposition technique. Single Cr2O3, Al2O3, Nd2O3 and codeposited Cr2O3–Nd2O3, Al2O3–Nd2O3, Al2O3–Sm2O3 coatings drastically improved the chromia-forming alloy high temperature oxidation behavior, since they decreased the oxidation rate and enhanced the oxide scale adhesion. Re…

Matter Transport and Corrosion Kinetics of Metals and Alloys at High Temperature

Mechanisms Involved by Reactive Elements upon High Temperature Chromia Scale Growth

The influence of Y 2 O 3 , Pr 2 O 3 , Nd 2 O 3 , Sm 2 O 3 and Yb 2 O 3 coatings on Fe-30Cr alloy oxidation behaviour was investigated at 1000°C in air under atmospheric pressure. Isothermal exposures indicated that the Y 2 O 3 coating was the most protective after 100 hours. Pr 2 O 3 , Nd 2 O 3 and Sm 2 O 3 coatings were less effective, but the less beneficial effect was observed when Yb 2 O 3 coating was applied onto the Fe-Cr alloy surface. Two-stage oxidation experiments in 16 O 2 and then 18 O 2 were performed to get information about the chromia growth phenomena with and without reactive elements. The 18 O-tracer distribution was determined by secondary ion mass spectrometry (SIMS) and…

A New Insight in the Electrochemical Response of a Depassivated Surface

The effect of rare earths deposited on steel surfaces, by different processes (sol/gel, electrophoresis, OMCVD), on high temperature corrosion behaviour

Abstract In this paper, different methods of rare earth oxides deposition on the surface of AISI 304 steel are described: sol/gel, electrophoresis in aqueous or organic medium, OMCVD of rare earth β-diketonates. After the deposition, all the samples were reheated. This treatment was absolutely essential for a strengthening effect of the protective oxide scale. Oxidation of coated and non-coated samples was performed under isothermal and cyclic conditions. The effect of rare earth deposition is significant in isothermal conditions. However, in thermal cyclic conditions, the effect of a rare earth deposited on surface is spectacular. Scale spallation is then completely avoided under the chose…

The Effect of Deposited Rare Earth Oxide Films on High Temperature Corrosion Behaviour of Different Metals and Alloys