Steam effects on cyclic oxidation of chromia forming alloys

Norinsan Kamil Othman, J. Zhang, D. J. Young

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Six model Fe-Cr alloys (Cr: 9-30 wt %) were subjected to cyclic oxidation in Ar-10%H 2-5%H 2O (p O2 =1.1 × 10 -1 atm), Ar-20%O 2 and Ar-20%O 2-5%H 2O atmospheres at 950°C. Oxidation weight change measurements showed that in general, increasing Cr content reduced the oxidation rate. At Cr ≤ 17%, breakaway oxidation was observed. However, for Cr ≥ 25%, the weight gain became very low due to the formation of Cr 2O 3 layer. Adding steam to Ar-20%O 2 accelerated the oxidation rate of alloys with Cr ≤ 20%. However, this accelerating effect did not appear for high chromium content alloys. XRD analysis showed that for low Cr content alloys (Cr ≤20%), wustite and spinel were formed in low p O2 gas, while in high p O2 gas, hematite, iron oxide and spinel were present. For high Cr content alloys only Cr 2O 3 was detected. Cross-section analysis showed that the spinel was formed by internal oxidation. The thickness and size of this internal oxide increased with increasing Cr content. A dense chromia layer was observed when the Cr content was above 25%. The oxide scales formed in steam were more porous and less compact than the scale formed in dry oxygen. The accelerating effect of water vapour on Fe-Cr oxidation is discussed in terms of gas-solid interactions.

Original languageEnglish
Title of host publication47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007
Pages864-875
Number of pages12
Publication statusPublished - 2007
Externally publishedYes
Event47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007 - Sydney, NSW
Duration: 4 Dec 20075 Dec 2007

Other

Other47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007
CitySydney, NSW
Period4/12/075/12/07

Fingerprint

steam
oxidation
spinel
gas-solid interactions
boundary layer separation
oxides
hematite
gases
iron oxides
water vapor
chromium
atmospheres
cross sections
oxygen

Keywords

  • Breakaway oxidation
  • Fe-Cr alloys
  • Internal oxidation and Cr O
  • Steam

ASJC Scopus subject areas

  • Surfaces and Interfaces

Cite this

Othman, N. K., Zhang, J., & Young, D. J. (2007). Steam effects on cyclic oxidation of chromia forming alloys. In 47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007 (pp. 864-875)

Steam effects on cyclic oxidation of chromia forming alloys. / Othman, Norinsan Kamil; Zhang, J.; Young, D. J.

47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007. 2007. p. 864-875.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Othman, NK, Zhang, J & Young, DJ 2007, Steam effects on cyclic oxidation of chromia forming alloys. in 47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007. pp. 864-875, 47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007, Sydney, NSW, 4/12/07.
Othman NK, Zhang J, Young DJ. Steam effects on cyclic oxidation of chromia forming alloys. In 47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007. 2007. p. 864-875
Othman, Norinsan Kamil ; Zhang, J. ; Young, D. J. / Steam effects on cyclic oxidation of chromia forming alloys. 47th Annual Conference of the Australasian Corrosion Association 2007: Corrosion Control 2007. 2007. pp. 864-875
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