The influence of the moisture content of the atmosphere on alumina scale formation and growth during high temperature oxidation of PM2000

Al‐Badairy, H.; Tatlock, G. J.

doi:10.1179/mht.2000.020

Cited by 32 publications

(13 citation statements)

References 1 publication

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“…However, some investigators report on the influence of water vapor on oxidation behavior [4,[12][13][14][15][16][17][18][19]. Kvernes et al report that water vapor has little influence on the oxidation of a FeCrAl alloy at 680-980°C [17].…”

Section: Introductionmentioning

confidence: 98%

The Effect of Water Vapor on the Initial Stages of Oxidation of the FeCrAl Alloy Kanthal AF at 900 °C

et al. 2007

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The effect of water vapor on the initial stages of oxidation of the FeCrAl alloy Kanthal AF is reported. Polished samples were exposed isothermally at 900°C for 1, 24, 72 and 168 h in a well-controlled environment consisting of dry O 2 or O 2 + 40% H 2 O. The samples were investigated using a combination of gravimetry and several surface-analytical techniques, including XRD, SEM, EDX, FIB, AES and TEM. The presence of water vapor significantly accelerates oxidation during the first 72 h. A two-layered oxide forms in both the dry and wet environments. The bottom layer consists of inward-growing a-Al 2 O 3 while the outer layer initially consists of outward-growing c-Al 2 O 3 . A straight and narrow Cr-enriched band is present at the top of the lower (a-Al 2 O 3 ) oxide, corresponding to the original sample surface. In dry O 2 , the top (c-Al 2 O 3 ) layer is converted into a mixture of c-Al 2Àx (Mg,Fe) x O 3À(x/2), MgAl 2 O 4 and a-Al 2 O 3 . This transformation does not occur in O 2 + H 2 O. The initial acceleration of oxidation by H 2 O is attributed to the stabilization of the outward-growing c-alumina layer by the hydroxylation of the c-Al 2 O 3 surface. A schematic mechanism of the early stages of oxidation of FeCrAl alloys is presented, emphasizing the influence of water vapor.

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Section: Introductionmentioning

confidence: 98%

The Effect of Water Vapor on the Initial Stages of Oxidation of the FeCrAl Alloy Kanthal AF at 900 °C

et al. 2007

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“…Moreover, the literature is somewhat contradictory [10]. Some groups report lower oxidation rates in the presence of water vapour at about 1,000°C [11,12], whereas others report that the presence of water vapour accelerates oxidation initially at 900°C [13] and at 1,300°C [14]. It has also been reported that once a continuous Al 2 O 3 scale has been formed, the oxidation is not significantly dependent on the water vapour content [15,16].…”

Section: Introductionmentioning

confidence: 99%

The Oxide Scales Formed on a Dispersion-Strengthened Powder Metallurgical FeCrAl Alloy at 900 °C in O2 and in O2 + H2O

et al. 2015

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Early oxide scale growth on an oxide dispersion strengthened rapidly solidified powder FeCrAl material, Kanthal Ò APMT, was investigated at 900°C in an O 2 ? N 2 and an O 2 ? H 2 O ? N 2 environment for up to 168 h. Gravimetry was used to follow oxide growth and the oxide scale was examined with XRD. Scale morphology was investigated in detail with SEM/EDX, TEM/EDX/CBED. The alloy rapidly formed a protective two-layered a-alumina scale containing oxide nodules. Between the top and bottom alumina layers there was a zone containing chromia-rich particles 5-20 nm in diameter, corresponding to the original sample surface. The alumina scale mainly grew inward after 1 h of oxidation. Alumina scale growth at 900°C was initially somewhat faster in an O 2 ? H 2 O ? N 2 environment than in an O 2 ? N 2 environment.

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“…However, the reports are somewhat contradictory. Some researchers report lower oxidation rates in the presence of water vapour [9,16] while others report that water vapour accelerates oxide growth [13,17,18].…”

Section: Introductionmentioning

confidence: 99%

Oxidation of a Dispersion-Strengthened Powder Metallurgical FeCrAl Alloy in the Presence of O2 at 1,100 °C: The Influence of Water Vapour

et al. 2015

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The oxidation behaviour of the FeCrAl alloy Kanthal Ò APMT in O 2 ? N 2 and O 2 ? N 2 ? H 2 O environments at 1,100°C was investigated using thermogravimetry and detailed analyses of the scale morphology with SEM/EDX and STEM/EDX. Wrought FeCrAl alloy Kanthal Ò AF was used as a reference. Exposure time was up to 168 h. Water vapour influenced the early oxide growth kinetics. This effect is explained in terms of water acting as an oxidant, simultaneously with O 2 . During later stages of the exposures, H 2 O had no effect on the kinetics of oxidation.

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The influence of the moisture content of the atmosphere on alumina scale formation and growth during high temperature oxidation of PM2000

Cited by 32 publications

References 1 publication

The Effect of Water Vapor on the Initial Stages of Oxidation of the FeCrAl Alloy Kanthal AF at 900 °C

The Effect of Water Vapor on the Initial Stages of Oxidation of the FeCrAl Alloy Kanthal AF at 900 °C

The Oxide Scales Formed on a Dispersion-Strengthened Powder Metallurgical FeCrAl Alloy at 900 °C in O2 and in O2 + H2O

Oxidation of a Dispersion-Strengthened Powder Metallurgical FeCrAl Alloy in the Presence of O2 at 1,100 °C: The Influence of Water Vapour

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