Paper Title:
Discussions on some Properties of Alumina Scales and their Protectiveness
  Abstract

This small review deals mainly with three issues regarding the nature and protectiveness of alumina scales grown during high-temperature oxidation: (1) sequences of phase transportation of alumina scales formed on Fe-Cr-Al and NiAl alloys, and a few aluminides, (2) combined additions of reactive element (RE) and (3) convolution of α-Al2O3 scales. Though the general phase transformation sequence of alumina scales is γ to θ to α phases at intermediate temperatures, variations have been reported. Directional growth of transient aluminas such as γ-Al2O3 and θ-Al2O3 is discussed with a particular emphasis on its driving force. Parabolic rate constants for the growth of α-Al2O3 scales are smaller when the period of transient alumina is longer because of larger α-Al2O3 grains. The effect of RE in slowing the parabolic oxidation saturates at a certain concentration, however combined addition further decreases the oxidation rate. The α-Al2O3 scales on Fe-Cr-Al alloys without RE are highly convoluted, however those on NiAl and other aluminides are not so convoluted. The α-Al2O3 layer beneath the outer NiO layer or NiAl2O4 layer is flat in the oxidation of Ni3Al. Directions for future work are proposed.

  Info
Periodical
Edited by
Toshio Maruyama, Masayuki Yoshiba, Kazuya Kurokawa, Yuuzou Kawahara and Nobuo Otsuka
Pages
51-56
DOI
10.4028/www.scientific.net/MSF.696.51
Citation
S. Taniguchi, "Discussions on some Properties of Alumina Scales and their Protectiveness", Materials Science Forum, Vol. 696, pp. 51-56, 2011
Online since
September 2011
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: Christophe Issartel, Henri Buscail, Eric Caudron, Régis Cueff, Frédéric Riffard, S. El Messki, N. Karimi, Laurent Antoni
69
Authors: X.J. Zhang, Yan Niu
Abstract:Small amounts of silver have been added to the intermetallic compound β-NiAl for the purpose of improving its mechanical properties. Four...
775
Authors: N. Mu, Takeshi Izumi, L. Zhang, Brian Gleeson
Abstract:Many high-temperature coatings rely on the formation of a continuous and adherent thermally grown oxide (TGO) scale of α-Al2O3 for extended...
239
Authors: Jerzy Jedlinski, Zbigniew Żurek, Martah Homa, G. Smoła, J. Camra
Abstract:The oxidation mechanism of FeCrAl (+RE), RE: reactive elements: Y and Hf) thin foils was studied at temperatures ranging from 1093 K to 1173...
541
Authors: F. Riffard, Henri Buscail, F. Rabaste, Christophe Issartel, Sébastien Perrier
Chapter 6: Diffusion and Corrosion Processes
Abstract:Phosphoric acid treatment is used as a way to improve the high temperature oxidation resistance of a chromia-forming AISI 304 steel....
359