The role of secondary oxide inclusions (“pegs”) on the spalling resistance of oxide films

Mennicke, C.; He, Ming; Clarke, David R.; Smith, J. S.

doi:10.1016/s1359-6454(00)00081-1

Cited by 52 publications

(13 citation statements)

References 17 publications

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“…Close inspection of the location of the Y-rich oxide inclusions revealed that for both alloys almost all inclusions were formed above alloy grain or phase boundaries (Fig. 2), in agreement with previous reports [13,17,28,29]. In some samples, internal oxidation of Y in advance of the O/M interface was observed, but the total amount of internally oxidized Y was very small compared with the amount of Y oxides within the scale.…”

Section: Microstructural Observationssupporting

confidence: 90%

Effect of Y Distribution on the Oxidation Kinetics of NiCoCrAlY Bond Coat Alloys

Nijdam

Sloof

2007

Oxid Met

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The relation between the Y distribution in the alloy and the growth kinetics of the developing oxide scale was studied for the thermal oxidation of two .2Y (at.%) alloys at 1,373 K: (i) a coarse-grain cast alloy with large Ni 5 Y intermetallic precipitates, and (ii) a fine-grain freestanding coating with small Ni 5 Y precipitates. Using a combination of experiments and model calculations, it is shown that the average growth kinetics of a NiCoCrAlY alloy are dependent on the size and distribution of Y-rich oxide inclusions (pegs) in the a-Al 2 O 3 oxide layer. Alumina scales containing a high density of small Y-oxide inclusions grow faster than a-Al 2 O 3 scales containing only a few, large Y-oxide inclusions. Upon oxidation of the freestanding coating, the Y-oxide inclusions in the scale attain their maximum size after the Y in the coating is completely consumed. After this point, a decrease in the average oxidation kinetics occurs.

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Section: Microstructural Observationssupporting

confidence: 90%

Effect of Y Distribution on the Oxidation Kinetics of NiCoCrAlY Bond Coat Alloys

Nijdam

Sloof

2007

Oxid Met

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“…As a result, pegs with a Dy-rich oxide "core" and an outer Al 2 O 3 "sheath" are generated which pin the oxide scale to the alloy beneath. The same peg formation mechanism has been reported by Mennicke [33]. For the existence of these pegs, when the oxide scale is spalling, the cracks must cut through or bypass the pegs, which would cost more energy.…”

Section: Discussionsupporting

confidence: 70%

The role of Dy and Hf doping on oxidation behavior of two-phase (γ′ + β) Ni–Al alloys

Zhang

Peng

et al. 2015

Corrosion Science

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“…13 Plot of increase in TGO thickness vs time at temperature with prediction using Eq. 5 segregation and the formation of yttria and yttrium-aluminate pegs and the effect on TBC life has been reported in the literature [3,[17][18][19][20][21]. Yttrium has a high affinity with oxygen and thus readily forms an oxide or yttrium aluminium garnet (YAG), in the presence of aluminium.…”

Section: Resultsmentioning

confidence: 99%

Oxidation Study of an EB-PVD MCrAlY Thermal Barrier Coating System

et al. 2011

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In this paper the oxidation kinetics data on a TBC system where the NiCoCrAlY bond coat and the YSZ topcoat are both applied by the EB-PVD process are presented. The oxidation testing was performed at 950, 1050 and 1150°C with times up to 1000 h. SEM analysis and modelling of the TGO growth rate show that the TGO is formed in two stages and that the initial oxide formed during the manufacture of the topcoat is non-protective. A global expression is derived for the oxidation kinetics at the three temperatures.

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The role of secondary oxide inclusions (“pegs”) on the spalling resistance of oxide films

Cited by 52 publications

References 17 publications

Effect of Y Distribution on the Oxidation Kinetics of NiCoCrAlY Bond Coat Alloys

Effect of Y Distribution on the Oxidation Kinetics of NiCoCrAlY Bond Coat Alloys

The role of Dy and Hf doping on oxidation behavior of two-phase (γ′ + β) Ni–Al alloys

Oxidation Study of an EB-PVD MCrAlY Thermal Barrier Coating System

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