Paper Title:
Application of 18O2 Exposure–Based Approach to Study the Failure Mechanisms of Oxide Scales on Alumina Formers
  Abstract

The 18O2 exposure-based approach was used to investigate the failure mechanisms of the oxide scales growing on alumina-forming materials. The scale spallation mechanisms and cracking processes were studied at various oxidation stages of FeCrAl alloys and β-NiAl intermetallic compound. High spatial resolution SIMS was applied to determine the distribution of the oxygen isotopes and other elements in the scales. It was found that the scales spall away according to an adhesive mode. However, t is process usually occurs at temperatures high enough to cause the reoxidation of the exposed bare substrat which results in thin oxide film on the metal. The thickness of this film and its composition depend on the alloy and the region at the interface. Spallation on reactive-element free FeCrAl alloys occurs at relatively high temperatures and the film is fairly thick, while on Zr-containing material very thin oxide layer is formed because the scale is better resistant to spalling and this process occurs at quite low temperature. The thin oxide layer formed on smooth regions comprises essentially the alumina, while the sequence of iron, chromium and aluminium oxide appears on regions exhibiting 'oxide imprints'. The applied approach enabled to find that the through-scale cracking observed at early oxidation stages of β-NiAl occurs at high temperatures and not during cooling. Formation of such cracks affects the further growth of the scale in terms of its microstructure, morphology and generation of stresses. Oxygen inward penetration through cracked scales formed during thermal cycling of FeCrAl alloys occurred mainly via oxide grain boundaries.

  Info
Periodical
Edited by
B.G. Wendler, P. Kula and J. Jedlinski
Pages
149-164
DOI
10.4028/www.scientific.net/MSF.513.149
Citation
J. Jedlinski, "Application of 18O2 Exposure–Based Approach to Study the Failure Mechanisms of Oxide Scales on Alumina Formers ", Materials Science Forum, Vol. 513, pp. 149-164, 2006
Online since
May 2006
Authors
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: Shi Yu Qu, Ya Fang Han, Jin Xia Song, Yong Wang Kang
Abstract:The effects of Cr and Al on high temperature oxidation resistance of Nb-Si system intermetallics have been investigated by scanning electron...
1485
Authors: Xu Dong Lu, Ce An Guo, Jie Wang, Shu Wu Ma
Chapter 1: Metal Materials
Abstract:The cyclic oxidation behaviour of Ni 5.5Al 2.6Ti 4.8Co 3.9Mo 5.0W 11.0Cr superalloy at 900 °C in air has been investigated by means of...
51
Authors: Xiang Long Yu, Dong Bin Wei, Xiao Dong Wang, Zheng Yi Jiang
Chapter 3: Materials Forming
Abstract:An experimental method was developed to study the adherence properties of the oxide scale formed on microalloyed low carbon steel after hot...
622
Authors: Patrick Ganster, Bagas Pujilaksono, Krzysztof Wolski
Chapter 6: Diffusion and Corrosion Processes
Abstract:Ni-14wt%W model-alloy has been used to study the kinetics and the mechanism of high temperature internal oxidation in presence of an external...
321
Authors: Peng Song, Jian Sheng Lu
Chapter 2: Material Science, Materials Processing and Manufacturing Processes Technology
Abstract:Pt-modified nickel aluminide coatings have been more widely used for protection of jet-engine components against high-temperature oxidation....
383