Water vapour effects on chromia forming alloys during cyclic oxidation

Organized by School of Materials Engineering & Sustainable Engineering Research Cluster, 1st - 2nd December 2009 at Putra Brasmana Hotel, Kuala Perlis, Perlis.

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Main Authors: N.K., Othman, Azman, Jalar, N., Othman
Other Authors: insan@ukm.my
Format: Working Paper
Language:English
Published: Universiti Malaysia Perlis 2010
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Online Access:http://dspace.unimap.edu.my/xmlui/handle/123456789/7512
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spelling my.unimap-75122010-01-18T13:31:58Z Water vapour effects on chromia forming alloys during cyclic oxidation N.K., Othman Azman, Jalar N., Othman insan@ukm.my Fe-Cr alloys Water vapour Breakaway oxidation Internal oxidation Cr2O3 Oxidation Alloys Materials engineering Organized by School of Materials Engineering & Sustainable Engineering Research Cluster, 1st - 2nd December 2009 at Putra Brasmana Hotel, Kuala Perlis, Perlis. Fe-Cr model alloys (Cr: 9, 17, and 25 wt %) were subjected to cyclic oxidation in Ar-20O2, Ar-20O2-5H2O and Ar-10H2-5H2O (pO2= 3.6 x 10-22 atm) all in volume % atmospheres at 700oC. In general, increasing alloy chromium levels reduced the oxidation rate. At high pO2, in the absence of water vapour, the 9%Cr alloy exhibited breakaway oxidation at the early stage of the reaction. However, for chromium levels ≥ 17%, no breakaway oxidation occurred, and the weight gain was very low. Adding water vapour to Ar-20O2 accelerated the oxidation of alloys containing ≤17% Cr. However, this accelerating effect was not evident for Fe25Cr alloy. At low pO2, breakaway oxidation of alloys with chromium concentration ≤ 17% occurred after 300 cycles. Fe25Cr alloy did not undergo significant oxidation. XRD and metallographic analyses showed that for Fe25Cr alloy, only thin Cr2O3 layer was formed. However, for other low chromium content, hematite, magnetite and spinel were also detected in the form of different layers in the thick oxide scale. An internal oxide zone with spinel was also formed for these low Cr alloys. The synergistic effects of water vapour and temperature cycling are discussed in terms of alloy chromium depletion and the affects of the H2O(g) on oxide transport properties. 2010-01-18T13:30:42Z 2010-01-18T13:30:42Z 2009-12-01 Working Paper p.1-5 http://hdl.handle.net/123456789/7512 en Proceedings of the Malaysian Metallurgical Conference '09 (MMC'09) Universiti Malaysia Perlis
institution Universiti Malaysia Perlis
building UniMAP Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaysia Perlis
content_source UniMAP Library Digital Repository
url_provider http://dspace.unimap.edu.my/
language English
topic Fe-Cr alloys
Water vapour
Breakaway oxidation
Internal oxidation
Cr2O3
Oxidation
Alloys
Materials engineering
spellingShingle Fe-Cr alloys
Water vapour
Breakaway oxidation
Internal oxidation
Cr2O3
Oxidation
Alloys
Materials engineering
N.K., Othman
Azman, Jalar
N., Othman
Water vapour effects on chromia forming alloys during cyclic oxidation
description Organized by School of Materials Engineering & Sustainable Engineering Research Cluster, 1st - 2nd December 2009 at Putra Brasmana Hotel, Kuala Perlis, Perlis.
author2 insan@ukm.my
author_facet insan@ukm.my
N.K., Othman
Azman, Jalar
N., Othman
format Working Paper
author N.K., Othman
Azman, Jalar
N., Othman
author_sort N.K., Othman
title Water vapour effects on chromia forming alloys during cyclic oxidation
title_short Water vapour effects on chromia forming alloys during cyclic oxidation
title_full Water vapour effects on chromia forming alloys during cyclic oxidation
title_fullStr Water vapour effects on chromia forming alloys during cyclic oxidation
title_full_unstemmed Water vapour effects on chromia forming alloys during cyclic oxidation
title_sort water vapour effects on chromia forming alloys during cyclic oxidation
publisher Universiti Malaysia Perlis
publishDate 2010
url http://dspace.unimap.edu.my/xmlui/handle/123456789/7512
_version_ 1643788847965798400
score 13.214268